Diseases and Medical Conditions Summary

Updated: 13.01.2021

Diseases and Medical Conditions Summary

Disease: a particular abnormal condition, a disorder of structure or function, that affects part or all of an organism
Acquired disease: began at some point during one's life, at any time after birth
Hereditary disease: caused by mutations that usually run in the family
Chronic disease: persists over time, usually for at least six months, and can last for the rest of the patient's life
Progressive disease: typically worsens over time until a serious state, organ failure and death
Incurable disease: cannot be cured, but sometimes the symptoms can be treated
Terminal disease: expected to have the inevitable result of death

Diseases that Cause most Deaths Worldwide:
1. ischemic heart disease - 15,5%
2. stroke - 11,1%
3. lower respiratory infections (influenza, pneumonia, bronchitis, tuberculosis) - 5,7%
4. chronic obstructive pulmonary disease - 5,6%
5. respiratory cancers - 3%
6. diabetes - 2,8%
7. dementias - 2,7%
8. dehydration and diarrhea - 2,4%
9. tuberculosis - 2,4%
10. cirrhosis - 2,1%

          Plague is an infectious disease caused by the bacterium Yersinia pestis. It is an epidemic disease with high mortality. It has three forms, bubonic, septicemic and pneumonic. There is a vaccine and about 10% of patients die even with treatment. It has historically occured in large outbreaks, best known is the 14th century Black Death.
          Pestilence is any infectious disease that is highly contagious. It is also a deadly epidemic, but it can have many causes. There were many pandemics in history, for example the Spanish flu of 1918 or cholera outbreaks. Some occurences in history have unknown causes.

          An epidemic is the rapid spread of a disease among a given population in a short time. It affects an exceptionally high portion of the population in an area.
          A pandemic is an epidemic spread to multiple countries, continents or even worldwide. It affects a large number of people.
          Quarantine is the separation of people who may be infected. On the other hand, medical isolation is the separation of people who are known to be infected.

Diseases of Affluence - Diseases of Rich People - Civilisation Diseases

Diseases of affluence: mostly chronic non-communicable diseases and other conditions associated with lifestyle and social conditions, include diabetes, asthma, ischemic heart disease, stroke, dementia, obesity, hypertension, cancer, alcoholism, gout, allergy, depression, mental illness and other mental health conditions
          Obesity: excess body fat has accumulated to an extent that it may have a negative effect on health, mainly caused by lifestyle, unhealthy diet, overeating and not enough physical activity
          Cancer: groups of cells show abnormal and uncontrolled growth, destroy adjacent tissues and sometimes metastaze or spread to other locations in the body, treatment includes chemotherapy, radiotherapy and surgery

Diseases of Poverty - Diseases of Poor People

Diseases of Poverty: mostly infectious diseases or conditions which are the result of poor living conditions, risk factors include poor housing and working conditions, inadequate sanitation, exposure to sick people, malnutrition, contaminated water, stress, overwork, inadequate education, and minimal health care, these include tuberculosis, AIDS, neglected diseases, malaria, parasites, asthma and dental decay
          Tuberculosis: a lung condition caused by bacteria called Mycobacterium tuberculosis, a treatable airborne bacterium, main symptom is coughing
          AIDS: caused by the human immunodeficiency virus, patients unable to fight off diseases and the patient usually dies of common respiratory infections, spread by unprotected sex, contaminated blood transfusions, hypodermic needles and from mother to child

Childhood Diseases

Childhood diseases: easy transmission of contagious diseases, diseases of young children include measles and tetanus, and older children include chickenpox, the fifth disease, mononucleosis, mumps, polio, rubella, scarlet fever and many others
          Chickenpox: highly contagious viral disease, symptoms include coughing, sneezing and a rash with pink bumps, sometimes also fever, appetite loss and headache
          Measles: highly contagious infection of the respiratory system that is caused by a virus, have cold-like symptoms (cough, runny nose), followed by a red flat rash with white spots, sometimes also high fever, fatigue and soggy eyes

Common Illnesses

Common illnesses: usually not very serious, spread worldwide
          Common cold: a viral illness which affects the upper respiratory tract, symptoms include cough, headache, sneezing, sore throat, runny and stuffy nose, there is no vaccine
          Influenza: a more serious viral infection of the upper respiratory tract, symptoms are more serious than a common cold, they include fever, weakness, shivering, dry cough and severe headache, stomach flu usually involves diarrhea, vomiting and loss of appetite

Diseases of the Respiratory System - Respiratory Diseases

Respiratory Diseases: pathological conditions affecting the gas exchange, mild include common cold, influenza and pharyngitis, serious include pneumonia, pulmonary embolism, tuberculosis, asthma, lung cancer and severe acute respiratory syndromes

          Pneumonia: bacterial caused usually by a streptococcus infection, the bacteria resides asymptomatically in healthy people, but in individuals with a weaker immune system the bacteria can become pathogenic

          Asthma: a long-term inflammatory diseases, caused by a combination of genetic and environmental factors, variable symptoms such as airflow obstruction and bronchiospasms, wheezing, coughing, chest tightness and shortness of breath, treatable but incurable disease

Diseases of the Digestive System - Gastrointestinal Diseases

Gastrointestinal Diseases: many diseases and conditions include infections, inflammation and cancer, for example appendictis, ileitis, colitis, diverticular disease, Crohn's disease, ulcerative colitis, IBS irritable bowel syndrome and funcional disorders

           Appendicitis: inflammation of the appendix located at the caecum, potentially fatal condition if left untreated, usually requires surgical intervention, symptoms include right lower abdominal pain, nausea, vomiting and decreased appetite

          Crohn's Disease: chronic inflammatory disease connected with immunodeficiency, symptoms include abdominal pain, diarrhea, fever, abdominal distension and weight loss, there can be severe complications

Diseases and Medical Conditions

Updated: 26.02.2020

Diseases and Medical Conditions

A disease is a particular abnormal condition, a disorder of structure or function, that affects part or all of an organism. The study of diseases is called pathology. A disease is often constructed as a medical condition associated with specific symptoms and signs. It may be causes by external factors such as pathogens, or by internal dysfunctions, particularly of the immune system. There are four main types of disease, infectious disease, deficiency disease, genetic disease (hereditary and non-hereditary) and physiological diseases.
          In a broader sense, disease includes injuries, disabilities, disorders, syndromes, isolated symptoms, deviant behaviors and atypical variations of structure and function. Death due to disease is called death by natural causes. A disorder is a functional abnormality or disturbance, such as a mental disorder which is a complex interaction of biological, social and psychological factors. A medical condition is a broad term that includes everything that normally receives medical treatment. A syndrome is the association of several medical sighs, symptoms and other characteristics that occur together and can have different causes.
          There are several causes of disease. An airborne disease is any disease that is caused by pathogens and transmitted through the air. Foodborne illness or food poisoning is any illness resulting from the consumption of food contaminated with pathogenic bacteria, viruses, toxins, prions or parasites. Infectious diseases, also called transmittable, contagious or communicable, are illnesses resulting from infection, it can spread from one person to another. A lifestyle disease is any disease that appears to increase in frequency in industrialized countries, the risk factors include sedentary lifestyle, unhealthy foods and pollution. A non-communicable disease is a medical condition that is non-transmissible, such as heart disease or cancer.
          An acquired disease is one that began at some point during one's life, at any time after birth. A genetic disease or disorder is caused by genetic mutation and is often inherited. So, an inherited or hereditary disease is a type of genetic disease caused by mutations that usually run in the family. An acute disease is one of a short-term nature, it can have a sudden onset and be severe. On the other hand, a chronic disease or condition is one that persists over time, usually for at least six months, and can last for the rest of the patient's life.
         An idiopathic disease has an unknown cause or source. An incurable disease cannot be cured, but sometimes the symptoms can be treated. A terminal disease is one that is expected to have the inevitable result of death. A progressive disease typically worsens over time until a serious state, organ failure and death. On the other hand, a stable or static disease does not get better or worse. A systemic disease affects the entire body. On the other hand, a localized disease affects only one part of the body. A primary disease is due to a root cause of illness. On the other hand, a secondary disease is a sequella or complication.
          Many diseases and disorders can be prevented through a variety of means, these include sanitation, proper nutrition, adequate exercise, vaccinations and other self-care and public health measures.

Diseases that Cause most Deaths Worldwide

Historically, the deadliest disease ever by estimated death toll was the plague. The Black Death, caused by the bacterium Yersinia pestis, killed something from 75 to 200 million people between 1331 and 1353, which at that time was 30 to 60% of the world's population. The plague struck in Europe, Asia and North Africa and was perhaps the most devastating pandemic in human history. Spanish Flu, a pandemic from 1918 to 1920, infected about 500 million people around the world. The result was from 50 to 100 million dead people, more than WWI.
          The statistics of deadliest diseases change over time, as medicine progresses. Several of the deadliest diseases are preventable, just like many risk factors to almost all main diseases. As healthcare progresses, causes and cures for many diseases are discovered. An increasing life span naturally leads to an increase in some health conditions. By mortality rates, the most dangerous are cardiovascular diseases with about 17,6% of cases, the second deadliest are infections and parasitic diseases and the third is cancer.
          Today, the deadliest disease in the world is coronary artery disease, also called ischemic heart disease. It occurs when the blood vessels that supply blood to the heart become narrowed. It can lead to chest pain, arrhythmias and heart failure, causing 15,5% deaths worldwide. The risk factors include high blood pressure, high cholesterol, smoking, diabetes, being overweight and family history of the disease.
          The second deadliest medical condition is a stroke, it causes 11,1% deaths worldwide. It occurs when an artery in the brain is blocked or leaks and causes the death of the oxygen-deprived brain cells within minutes. During a stroke, the patient can feel sudden numbness and confusion, have trouble walking and seeing. If left untreated, it can lead to long-term disabilities, patients should receive treatment within 3 hours of having a stroke. The risk factors include high blood pressure, smoking, being female, and family history of stroke.
          The third most deadliest diseases are lower respiratory infections which cause 5,7% deaths worldwide. These diseases include mainly influenza, pneumonia, bronchitis and tuberculosis. The main symptom is coughing, but also breathlessness, wheezing and a tight feeling in the chest. The risk factors include poor air quality or frequent exposure to lung irritants, smoking, a weak immune system and asthma.
          The fourth disease to cause most deaths worldwide is chronic obstructive pulmonary disease, about 5,6% of deaths. It is a long-term, progressive lung disease that makes breathing difficult. Chronic bronchitis and emphysema are types of this disease. Risk factors include smoking, lung irritants and family history of respiratory diseases. There is no cure but its progression can be slowed with medication.
          Respiratory cancers cause about 3% of deaths worldwide. They include the cancer of the trachea, larynx, bronchus and lungs. The main causes are smoking and secondhand smoke, environmental toxins and household pollutions, such as solid fuel emissions and mold.
          Diabetes is a group of diseases that affect insulin production and use, these cause about 2,8% deaths worldwide. Risk factors include excess body weight, high blood pressure, older age, not enough exercise and an unhealthy diet.
          Alzheimer's disease and other dementias cause 2,7% of deaths worldwide. Alzheimer's is a progressive disease that destroys memory and interrupts normal mental functions, including reasoning and typical behavior. From 60% to 80% cases are Alzheimer's disease, it is the most common type of dementia. It starts off by causing mild memory problems, but progresses. The risk factors include being older than 65, a family history of dementia, Down syndrome, unhealthy lifestyle, being female, previous head trauma and being socially isolated.
          Dehydration due to diarrheal diseases causes 2,5% of deaths worldwide. Lasting diarrhea can cause dehydration which can lead to death. It is usually caused by an intestinal virus or bacteria transmitted through contaminated water or food. It is the second top cause of death in children younger than 5 years. Risk factors include poor sanitary conditions, no access to clean water, malnourishment, a weakened immune system and being a young child.
          Tuberculosis causes 2,4% of deaths worldwide. It is a lung condition caused by bacteria called Mycobacterium tuberculosis, a treatable airborne bacterium. It is preventable by vaccination and most of the serious cases are from developing countries, because it spreads quickly among people who are malnourished and in overcrowded conditions. It is one of the top causes of death in people with HIV, about 35%. The risk factors include diabetes, HIV infection, a lowed body weight, proximity to others with tuberculosis and regular use of medications like corticosteroids and immunosuppressants.
          The tenth deadliest disease is cirrhosis which causes 2.1% of deaths worldwide. It is a result of chronic scarring and damage to the liver, caused by a kidney disease, conditions like hepatitis or chronic alcoholism. Risk factors include chronic alcohol abuse, fat accumulation around the liver and chronic viral hepatitis. Healthy diet low on sugar and fat can prevent the disease.

Deadliest Diseases

Some diseases are so dangerous that contracting the disease almost inevitably leads to death.
          African trypanosomiasis, simply called sleeping sickness, is an insect-borne parasitic disease. The symptoms are fevers, headache, itchiness and joint pain, and later trouble sleeping, confusion and poor coordination. Treatment is easier before neurological symptoms occur, without treatment the patient most surely dies.
          Rabies is a viral disease that causes inflammation of the brain. Symptoms include fever, fear of water, confusion, excessive salivation, violent movements, hallucinations, trouble sleeping, paralysis and coma. Once symptoms appear, the result is nearly always death. Vaccination after exposure is highly successful in preventing the disease, in unvaccinated humans, rabies is almost always fatal after neurological symptoms have developed. In 2003, Jeanna Giese became the first person known to survive rabies after symptom onset.
          Smallpox is an infectious disease caused by two viruses, Variola major and Variola minor. The last naturally occurring case was diagnosed in 1977 and the WHO certified the global eradication of the disease in 1980. The untreated disease was almost always deadly, the death risk of treated patients was about 30%, with higher rates among babies. Survivors had extensive scarring of skin and some were left blind. Early symptoms are fever, vomiting and mouth sores, later symptoms are fluid filled blisters which scab over. This disease is estimated to have killed up to 300 million people in the 20th century. Vaccination was discovered in 1798 by Edward Jenner and smallpox became one of two infectious diseases to have been eradicated.
          Human immunodeficiency virus HIV and acquired immune deficiency syndrome AIDS do not cause death by themselves, but they make humans unable to fight off diseases and the patient usually dies of common respiratory infections. HIV is spread by unprotected sex, contaminated blood transfusions, hypodermic needles and from mother to child. It is a retrovirus and there is no cure or vaccine. However, antiretroviral treatment can slow the course of the disease and may lead to near-normal life expectancy. Without treatment, the average survival time after infection is 11 years. Globally, about 37,9 million people are HIV positive, including 1,7 million children, and around 21% of these do not know that they have the virus.
          Ebola is a viral hemorrhagic fever caused by ebolavirus. Symptoms include fever, muscular pain, sore throat and headaches, followed by vomiting, diarrhea and rash with decreased function of the liver and kidneys. It is highly deadly and from 25% to 90% of infected patients die, with an average of about 50%.
          Influenza is an viral infectious disease of the upper respiratory tract that can be mild to severe. Most common symptoms include high fever, runny nose, sore throat, weakness, muscle and joint pain, headache, shivering, coughing and feeling tired. Stomach flu usually involves diarrhea, vomiting and loss of appetite. Humans are affected by types A, B and C and its yearly outbreaks result up to 5 million severe cases and up to 650 thousand deaths. It cannot be cured by antibiotics, they are prescribed to fight off a secondary bacterial infection. Death occurs mostly in high risk groups, the young, the old and those with other health problems. Most transmissions occur through hand-to-hand contact, so sanitation prevents infection. Since the 20th century, four pandemics have occured, in 1918, 1957, 1968 and 2009.
          Tetanus, also called lockjaw, is a bacterial infection characterised by muscle spasms that can be severe enough to cause bone fractures. Recovery may take month and about 10% of cases become fatal, unvaccinated and untreated cases have a 50% chance of survival. It can be prevented by immunization with tetanus vaccine and in 2015 the disease killed 59 thousand people.
          Tuberculosis is an infectious disease usually caused by Mycobacterium tuberculosis.  It is the leading cause of death around the world for an infectious disease. About a quarter of human population is thought to be infected, but most people have a latent form and they do not spread the disease. It is preventable by vaccination and most of the serious cases are from developing countries. The risk factors include diabetes, HIV infection, a lowed body weight, proximity to others with tuberculosis and regular use of medications like corticosteroids and immunosuppressants.

Diseases of Affluence - Diseases of Rich People - Civilisation Diseases

Diseases and health conditions of affluence are commonly thought to be a result of wealth in society. They occur more and more since the end of WWII. Examples of these diseases are mostly chronic non-communicable diseases and other conditions associated with lifestyle and social conditions. They include diabetes, asthma, ischemic heart disease, stroke, dementia, obesity, hypertension, cancer, alcoholism, gout, allergy, depression, mental illness and other mental health conditions.
          These diseases are a direct result of technological advances which lead to less physical exercise and an unhealthy diet. The life of modern people is less physically demanding and people exercise irregularly or not at all. Food is easily accessed and cheap fastfood is preferred. People consume more fat, meat, dairy and sugar if foods which are pre-prepared, processed and commercially provided. Tabacco and alcohol are abused frequently. Longer lifespans mean that more diseases have time to occur and increased cleanliness leads to increased occurrence of allergy and autoimmune diseases.

Obesity

It is the most wide-spread civilisation disease of our time. It is a medical condition in which excess body fat has accumulated to an extent that it may have a negative effect on health. People are considered obese when their BMI (body mass index) is over 30. It is more common in women than men and carries social stigma.
          In many countries there are over 30% obese people which is a big problem for the healthcare system. It is the leading preventable cause of death worldwide. It increases the risk of various diseases, especially heart problems, type 2 diabetes, some types of cancer and problems with the musculoskeletal system.
          It is mainly caused by lifestyle, unhealthy diet, overeating and not enough physical activity. A few cases are caused by genes, endocrine disorders, medication or psychiatric illnesses. This condition is mostly preventable through a combination of social changes and personal choices, especially changes to diet and exercising.
          The basic treatment are dieting and physical exercise. In serious cases of failure of basic treatment anti-obesity medication and surgery can be recommended to reduce appetite.

Cancer

It is a disease where groups of cells show abnormal and uncontrolled growth, destroy adjacent tissues and sometimes metastaze or spread to other locations in the body via lymph or blood. There are malignant and benign tumors that do not metastaze. Over a hundred types of cancer affect humans, the most common cancer types are lung, breast and prostate, skin, stomach and colorectal cancer.
          Common environmental factors leading to cancer include smoking, unhealthy diet and obesity, lack of physical activity and environmental pollutants. From 5 to 10% of cancers are due to inherited genetic defects.
          Most types of cancer can be treated, this includes chemotherapy, radiotherapy and surgery. Cancer can affect people of all ages and a few types are more common in children, like leukemia. Generally the risk of developing cancer increases with age and many cancers occur more commonly in developed countries.

Gout 

Gout is a form of inflammatory arthritis characterized by recurrent attacks of a red, tender, hot and swollen joint. It occurs due to persistently elevated levels of uric acid in the blood. At high levels, the acid crystallizes and deposits in joints, tendons and surrounding tissues, resulting in an attack.
          This disease occurs due to a combination of diet, other health problems and genetic factors. It occurs more commonly in those who regularly eat meat or seafood, drink beer and are overweight. From 1 to 2% of the Western population is affected by gout. Older males are most commonly affected and it was once known as the disease of kings.
          Am attack can be treated by medication that improves the symptoms. Medication and lifestyle changes are used for further prevention. Healthier diet should reduce purine-rich food and fructose.

Alcoholism

Alcohol abuse disorder is a broad term for any drinking of alcohol that results in mental or physical problems. This can affect all parts of the body, but particularly the brain, heart, liver, pancreas and immune system. It can result in mental illness, irregular heartbeat, liver cirrhosis, increased cancer risk and other health conditions. Alcoholism also reduces life expectancy by around ten years.
          Women are generally more sensitive to harmful effects of alcohol, but men abuse alcohol more commonly. The World Health Organization estimates that there are over 4% of alcoholics worldwide, in the USA it is 7% and in Eastern Europe, it is 11%.

Mental Illness

One in four people have experienced mental illness in their lives. China and the US are the countries with the highest levels of anxiety, depression and schizophrenia, the US is reported to have the highest level of depression worldwide. From 2% to 6% of people worldwide have depression, the same goes for anxiety disorders.
          A mental illness or a psychiatric disorder is a behavioral or mental pattern that causes significant distress or impairment or personal functioning. The causes are often unclear.
          Depression, major depressive disorder, is a mental disorder characterised by at least two weeks of low mood that is present across most situations. Anxiety is an emotion characterised by an unpleasant state of inner turmoil, often accompanied by nervous behaviour.
          Suicide is the act of killing oneself, sometimes it is impulsive, but many are premeditated. It is the tenth leading cause of death worldwide, causing death of 1,5% of people. Men are more likely to kill themselves, it is most common in people over 70, but in some countries people between 15 and 30 are at the highest risk. There are an estimated 10 to 20 million non-fatal attempted suicides every year. Attempted suicide is more common among young people and women.

Allergy and Autoimmune Diseases

The rate of allergies around the world has risen in industrialized nation since WWII. It is assumed that there are less allergies and autoimmune diseases in developing countries than in developed countries. A number of public health measures, such as sterilized milk, use of antibiotics and improved sanitation may have contributed to that.
          An allergy is a condition caused by hypersensitivity of the immune system to typically harmless substances in the environment. Food allergy is an immune reaction caused by the release of histamine, it is immediate. Food intolerance is a detrimental reaction, often delayed, that produces symptoms. It is a result of the absence of specific chemicals and enzymes needed to digest a food substance and it can be hereditary.
          Autoimmunity is the system of immune responses against its own healthy cells and tissues. There are at least 80 types of autoimmune diseases and the cause is generally unknown, some may be hereditary. Women are more commonly affected and in the US, about 7% of people are affected. The first autoimmune diseases were described in the early 1900s.

Diseases of Poverty - Diseases of Poor People

On the other hand, diseases of poverty are mostly infectious diseases or conditions which are the result of poor living conditions. These include tuberculosis, malaria, asthma, conditions related to malnutrition and poor health behaviour and HIV. Poor developing countries and regions are most affected. Risk factors include poor housing and working conditions, inadequate sanitation, exposure to sick people, malnutrition, contaminated water, stress, overwork, inadequate education, and minimal health care.
          Neglected tropical diseases are a diverse group of tropical infections which are common in low-income populations in developing regions. These diseases affect more than 1,4 billion people but are underfunded, although some treatments are relatively inexpensive. The combined total number of death due to these diseases is comparable to malaria and tuberculosis.
          Tuberculosis, an infectious disease usually caused by Mycobacterium tuberculosis, is the leading cause of death around the world for an infectious disease. It is especially spread in sub-Saharan Africa, Latin America and the Caribbean region. It spreads quickly among people who are malnourished and in overcrowded conditions. It is preventable by vaccination and most of the serious cases are from developing countries. The risk factors include diabetes, HIV infection, a lowed body weight, proximity to others with tuberculosis and regular use of medications like corticosteroids and immunosuppressants.
          AIDS, acquired immune deficiency syndrome, is most spread in eastern and southern Africa, less in western and central Africa. The disease is caused by HIV, human immunodeficiency virus. Globally, about 37,9 million people are HIV positive, including 1,7 million children, and around 21% of these do not know that they have the virus. It is spread by unprotected sex, contaminated blood transfusions, hypodermic needles and from mother to child. The disease was first clinically reported on June 5, 1981 in the US and it is believed to originate from primates in Africa. The disease makes humans unable to fight off diseases and the patient usually dies of common respiratory infections. It is a retrovirus and there is no cure or vaccine. However, antiretroviral treatment can slow the course of the disease and may lead to near-normal life expectancy. Without treatment, the average survival time after infection is 11 years.

Malaria

Malaria is a mosquito borne infectious disease that causes fever, tiredness, vomiting and headaches, and in severe cases yellow skin, seizures, coma and death. It is caused by single-celled microorganisms of the Plasmodium group and mostly spread by an infected female Anopheles mosquito. Five species can infect humans and most deaths are caused by Plasmodium falciparum.
          No effective vaccine exists and it is treated by antimalarial medication, usually in combination. The disease is widespread in tropical and subtropical regions around the equator. In 2018, there were 228 million cases of malaria worldwide, resulting in an estimated 405 thousand deaths, mostly in Africa.

Childhood Diseases

Children have maturing immune systems and are often together is classrooms or on school buses. This makes the transmission of contagious diseases particularly easy and explains why these diseases are so common in children. Contagious diseases are often caused by the spread of bacteria, such as scarlet fever, or viruses such as chickenpox. Diseases of young children include measles and tetanus. Diseases of older children include chickenpox, the fifth disease, mononucleosis, mumps, polio, rubella, scarlet fever and many others.

Chickenpox

Chickenpox, also known as varicella, is a highly contagious disease, that usually affects children. It is caused by VZV, varicella zoster virus. The infection spreads through fluids from the airways, such as from coughing and sneezing. The incubation period is 14-16 days, and the first sign of disease is a rash, small, itchy blisters which scab over and cannot be scratched because it will scar. Other symptoms include fever, tiredness and headaches. The most common complication is infection of lesions with bacteria. Rare complications include lung infection pneumonia or brain infection encephalitis. The disease is often more serious in adults than in children.

Measles

Measles is a highly contagious infection of the respiratory system that is caused by an airborne virus. The incubation period after the virus infects the upper respiratory tract is about 10 days. This child then has 3-4 days of cold-like symptoms, followed by a rash. The child is usually well after 2 weeks of illness and then has life-long immunity to the disease. Complications more commonly occur in children aged younger than 5 and adults older than 20. Serious complications of measles include blindness, inflammation of the brain caused by infection encephalitis, severe diarrhea that may lead to dehydration, ear infections and severe respiratory infections. The most common cause of death associated with measles is from pneumonia. The majority of deaths from measles occur in developing countries. Vaccination resulted in 80% decrease in deaths from measles since 2000.

Scarlet Fever

Scarlet fever is an infection with a type of bacteria called streptococcus which causes a throat infection and also produces a poison causing the distinctive rash. Some people are more sensitive to the toxin so not everyone will have the rash even if they have the throat infection. Incubation is 1-5 days. Symptoms are sore throat and vomiting. There are painful swollen glands in the neck. There is no rash on the face but flushed cheeks. The rash disapears within a week. Antibiotics are usually given for the disease. It is important to keep the child at home and avoid contact with other children. An untreated case may have peeling of the skin. It is contagious to people who come into close contact with an infected child. Complications are rare but can include deeper tissue infections, rheumatic fever and kidney disease.

Mononucleosis

Mononucleosis is an illness caused by the Epstein-Barr virus EBV which is spread through saliva. The most typical symptom is tiredness and sleepiness, combined with swollen lymph glands and spleen, sore throat, fever, loss of appetite and muscle aches. Many people have mild symptoms and don't know they were infected. Because the incubation period is very long, 30 to 50 days, it is almost impossible to avoid the infected. Fortunately, mononucleosis is not very contagious and is usually passed through kissing.

Common Illnesses

Common Cold

Cold is a viral illness which affects the upper respiratory tract. Symptoms include cough, headache, sneezing, sore throat, runny and stuffy nose. It typically lasts up to two weeks, but it is not very serious. Treatment includes cough drops, rest in bed, tea with lemon and drinking a lot of fluids.

Influenza

The flu is a viral infection of the upper respiratory tract. Symptoms are more serious than a common cold, they include fever, sore throat, weakness, muscle and joint pain, shivering, dry cough and severe headache. Stomach flu usually involves diarrhea, vomiting and loss of appetite. It is important to go to see a doctor when the patient has high fever, a persisting cough and sore throat and if the problems last more than 10 days. It cannot be cured by antibiotics, they are prescribed to fight off a secondary bacterial infection. Treatment of flu involves bed rest and drinking a lot of fluids.
          Vaccination is possible, but there are many strains of the virus. The person should be vaccinated 6 to 8 weeks before flu season. The virus is contagious during the first three days of illness and the incubation period is one to three days. Most transmissions occur through hand-to-hand contact, so sanitation prevents infection. Humans are affected by types A, B and C and its yearly outbreaks result up to 5 million severe cases and up to 650 thousand deaths. Death occurs mostly in high risk groups, the young, the old and those with other health problems. Since the 20th century, four pandemics have occured, in 1918, 1957, 1968 and 2009.

Conjunctivitis - Pink Eye

It is an inflammation of the transparent membrane that lines the eyelids and part of the eyeballs. It has several possible causes, a bacterial or viral infection, an allergic reaction or it can be a result of chemical irritants.
          The bacterial and viral type is highly contagious, so early diagnosis is important. Bacterial cases can be cured with antibiotic eyedrops. Viral conjunctivitis clears up on its own. Patients should try to prevent spreading the infection.

Headache

There are countless of causes of headaches and frequent and severe headaches should be consulted with a doctor. The most common causes of headache include stress, irregular sleep, alcohol abuse, changes in the weather and not enough fluids. Treatment includes ice packs or heating pads, rest, regular exercise and enough fluids.
          The three most common types are cluster, tension-type and migraine. A cluster headache affects a specific point of the head and is characterized by sharp and piercing pain. Tension headaches are dull and are usually caused by stress, poor posture and depression. A migraine is a disorder characterised by recurrent headaches that are pulsating and throbbing, and can last up to three days. Other symptoms of a migraine may include nausea, vomiting, sensitivity to light, sound and smell, and some include an aura visual disturbance.

First Aid Summary

Updated: 19.01.2021

First Aid Summary

First aid: first and immediate assistance in an emergency
First aid kit: supplies and equipnet used to give emergency medical treatment

Bleeding: blood escaping the body
          External bleeding: blood leaving the body through a wound
          Internal bleeding: blood collecting inside the body
          Arterial bleeding: from an artery, the blood is bright and flows quicky
          Venous bleeding: from a vein, the blood id dark and flows slowly

Asphyxiation: not breathing properly, defficient suppy of oxygen causes hypoxia

          Choking: object stuck in the throat or windpipe, blocks the air from flowing

          Strangling: compression of the neck, closure of the airways and arteries

CPR: cardiopulmonary resuscitation to manually preserve intact brain function
           30 chest compressions to 2 rescue breaths

Bone fracture: an X-ray necessary, treatment should involve immobilization, a splint can by applied to a broken limb, the wound shoud be cleaned and protected by sterile dressing



First aid is the first and immediate assistance given to any person suffering from illnes or injury. Its aim is to preserve life, prevent the condition from worsening and to promote recovery. An emergency usually involves loss of consciousness, heavy blood loss, suspected broken bones, chest pain lasting more than 15 minutes, difficulty breathing, overdose or poisoning. A first aid kit is a collection of supplies and equipment used to give medical treatment.
          The primary goals of first aid are the 5P's, preserve life, reduce the level of pain, prevent further harm, promote recovery and protect the unconscious.

Bleeding, also called hemorrhage, is blood escaping from the circulatory system from damaged blood vessels.
           External bleeding is when blood is leaving the body through a wound. Internal bleeding is a loss of blood that collects inside the body. The symptoms include coughing up or vomiting blood, faintness or dizziness, weak pulse and pale skin. This medical emergency should be treated immediately by medical professionals, the first aid giver should call to the emergency medical services, lay the patient down and check vital functions.
          Venous bleeding occurs when a vein is damaged, the blood is dark red and leaks slowly and steadily from the wound. First aid includes applying pressure and dressing, if a limb is wounded, lifting up the limb can also help.
          Arterial bleeding occurs when an artery is damaged, the blood is bright red to yellowish, sprays out of the wound and the patient is usually pale. First aid includes applying pressure and dressing, if a limb is wounded, lifting up the limb can also help. A tourniquet can also by used to slow the bleeding.

Asphyxiation is a condition of deficient supply of oxygen that arises from abnormal breathing. It causes generalized hypoxia, a pathological state of insufficient supply of oxygen.
          This can happen for example by choking, when an object becomes stuck in the throat or the windpipe and blocks air from flowing into the lungs. Symptoms include inability to speak, difficulty in breathing, violent coughing, clutching the throat, attempting to induce vomiting, change of colour in the face and unconsciousness. The basic treatment involves hard back slaps and then Heimlich maneuver. If the person loses consciousness, CPR is recommended.
          Drowning is defined as respiratory impairment as a result of being in a liquid, usually water. Symptoms following rescue may include breathing problems, vomiting, confusion and unconsciousness. Treatment should include opening the airway and performing CPR if the heart is not beating.
          Strangling is compression of the neck, it typically occurs in cases of violence and accidents. It can induce one or more conditions, some leading to death, including closure of arteries and veins and closure of the airway. The constriction from the neck should be immediately removed, while the body is supported. The patient should be moved as little as possible, in case of spinal injury. The patient should be laid down, the airway opened and CPR performed if necessary.

How to Perform CPR

CPR (cardiopulmonary resuscitation) is an emergency procedure that combines chest compressions often with artificial ventilation in an effort to manually preserve intact brain function in a person who is in cardiac arrest. It involves chest compressions for adults 5-6cm deep and at a rate of 100-120 per minute, set to breathing ratios at 30 to 2. It alone is unlikely to restart the heart, its main purpose is to delay tissue damage and death, especially brain damage. An untrained person may deliver hands-only CPR.

STEP 1: shake and stout
STEP 2: check breathing and bleeding
STEP 3: call emergency services
STEP 4: give 30 chest compressions
STEP 5: give 2 rescue breaths
STEP 6: repeat until help arrives

Other Conditions

A medical emergency is an acute injury or illness that poses an immediate risk to a person's life or health. These emergencies require assistance dependent of the severity of the condition.
           Anaphylaxis, a serious allergic reaction, occurs rarely with stings and insect bites. Symptoms include swelling, breathing difficulties, shortness of breath, vomiting, low blood pressure and a rash.  Swelling can be life-threatening and urgent medical attention is required. Carrying an epinephrine autoinjection and identification regarding the condition is recommended in people with a history of this condition.
          A bone fracture is a condition in which there is a partial or complete break in the bone, severe cases include bone broken into several pieces. Symptoms include pain, deformity, swelling and bruising, loss of function, inability to move, and in open fractures, bone protruding from the skin. Treatment should involve immobilization, a splint can by applied to a broken limb, the wound shoud be cleaned and protected by sterile dressing. Later treatment can involve surgical corrections.
          A burn is a type of injury to tissues caused by heat, cold, electricity, chemicals, friction or radiation. Treatment depends on the severity of the burn, major burns require prolonged treatment in specialized burn centres. Cooling with water may help pain and decrease damage, a sterile bandage can be applied. Clothing stuck to the skin should not be removed and ice and creams should not be applied. Scalding is a form of thermal burn resulting from heated fluids. Most scalds are considered first or second degree burns, but prolonged contact can cause more damage.
          A joint dislocation, also called luxation, occurs when there is an abnormal separation in the joint, often caused by sudden trauma. It can cause damage to the ligaments, tendons, muscles and nerves, symptoms include pain, joint instability and deformity, bruising, stiffness and difficulty moving. Reduction should be performed only by trained professionals, an untrained person can substantially worsen the injury. It is important that the joint is x-rayed and reduced as soon as possible and they are usually held in place by a splint or bandage.

First Aid

Updated: 20.02.2024

First Aid

First aid is the first and immediate assistance given to any person suffering from illnes or injury. Its aim is to preserve life, prevent the condition from worsening and to promote recovery. It includes initial intervention prior to professional medical help being available. It does not require any particular equipment or prior knowledge, it can involve improvisation by untrained people. It is about making common sense decisions in the best interest of the patient.
          An emergency usually involves loss of consciousness, heavy blood loss, suspected broken bones, chest pain lasting more than 15 minutes, difficulty breathing, overdose or poisoning.
          The primary goal of first aid is to preserve life, to prevent death or serious injury from worsening. The overriding aim of medical care is to save lives and minimize the threat of death.
          Done correctly, first aid should reduce the level of pain and calm the person down. The treatment process should alleviate suffering.
          First aid should prevent further harm, for example during transportation. The patient should be removed from the dangerous location and first aid should prevent worsening the condition.
          It should also try to start the recovery process. First aid should start the healing process and promote recovery.
          Part of first aid is also the protection of those, who cannot protect themselves. It is always important to protect the unconscious patients from any further harm.

A first aid kit is a collection of supplies and equipment used to give medical treatment. They are usually identified with a graphical first aid symbol, a cross and the colours red, white and green or the blue Star of Life on a white background. Common items may include iodine, bandages, hydrogen peroxide, disposable gloves, surgical masks, scissors, tweeters, lighters, thermometers and painkillers.

Protocols of first aid are based on the principle of defining the priorities and the procedure. The correct execution of the individual steps achieves the required objective of saving human life. These protocols require minimum resources, time and skills with a great degree of success in saving lives.

Bleeding - external and internal

Bleeding, also called hemorrhage, is blood escaping from the circulatory system from damaged blood vessels. Hypovolemia, or volume depletion, is a state of decreased intravascular volume. Exsanguination is the death by excessive loss of blood. Tpically, a healthy person can lose 10-15% of blood without serious medical difficulties. The stopping or controlling of bleeding is called hemostasis, it is an important part of first aid. A blood donation is when a person voluntarily gives blood for transfusions, it is stored in blood banks.
          Blood loss is broken down into four classes. Class I involves up to 15% of blood volume, there is no change in vital signs. Class II involves up to 30% of total blood volume, the patient is often tachycardiac (rapid heart beat), pale with cool skin and there is a change in blood pressure. Class II involves up to 40% of blood volume, the patient's blood pressure drops, the heart rate increases, shock occurs and a blood transfusion is usually necessary. Class IV involves the loss of more that 40% of blood volume, this is the limit of the human body and transfusion and resuscitation are required to prevent death.
          Internal bleeding is a loss of blood that collects inside the body. It is a serious medical emergency, the severity depends on the bleeding rate and the location of the bleeding. The symptoms include coughing up or vomiting blood, faintness or dizziness, weak pulse and pale skin. This medical emergency should be treated immediately by medical professionals, the first aid giver should call to the emergency medical services, lay the patient down and check vital functions.
          External bleeding is when blood is leaving the body through a wound.
               Capillary bleeding is normally not a serious condition and blood vessels are able to clot and stop it by themselves.
               Venous bleeding occurs when a vein is damaged, the blood is dark red and leaks slowly and steadily from the wound. Most veins will collapse when cut, which will help slow the bleeding, but a deep vein bleeding can be difficult to control. First aid includes applying pressure and dressing, if a limb is wounded, lifting up the limb can also help.
               Arterial bleeding occurs when an artery is damaged, the blood is bright red to yellowish, sprays out of the wound and the patient is usually pale. First aid includes applying pressure and dressing, if a limb is wounded, lifting up the limb can also help. A tourniquet can also by used to slow the bleeding.

Airway and Breathing

Asphyxiation is a condition of deficient supply of oxygen that arises from abnormal breathing. It causes generalized hypoxia, a pathological state of insufficient supply of oxygen. The complete deprivation of oxygen supply is referred to as anoxia.
          This can happen for example by choking, when an object becomes stuck in the throat or the windpipe and blocks air from flowing into the lungs. It is a common cause of unintentional injury-related death, especially for young children and the elderly. Symptoms include inability to speak, difficulty in breathing, violent coughing, clutching the throat, attempting to induce vomiting, change of colour in the face and unconsciousness. The basic treatment involves hard back slaps and then Heimlich maneuver. If the person loses consciousness, CPR is recommended.
          Carbon monoxide poisoning typically occurs from breathing in carbon monoxide at excessive levels. The CO is a colourless and odorless gas which is initially non-irritating, it has a higher affinity than oxygen to the hemoglobin and displaces it in red blood cells. Symptoms may resemble the flu, they include headache, dizziness, weakness, vomiting, chest pain and confusion. Large exposures can result in loss of consciousness, arrhythmia, seizure and death. Treatment generally consists of giving 100% oxygen and supportive care.
          Drowning is defined as respiratory impairment as a result of being in a liquid. Significant amounts of liquid usually only enter the lungs later during drowning. Symptoms following rescue may include breathing problems, vomiting, confusion and unconsciousness. Treatment should include opening the airway and performing CPR if the heart is hot beating.
          Strangling is compression of the neck, it typically occurs in cases of violence and accidents. It can induce one or more conditions, some leading to death, including closure of arteries and veins and closure of the airway. Compression of the jugular veins requires 6times less pressure than the trachea. Manual strangulation is called throttling, chokeholds are practiced in various martial arts and self-defense systems. Ligature strangulation, also called garroting, is strangling with some form of cord.
               Hanging is the suspension of a person by a noose around the neck, it is a common method of execution and of suicide. The strangling force is the person's own bodyweight. It can induce one or more conditions, some leading to death, including closure of arteries and veins, cervical fracture and spinal cord injury and closure of the airway.
                The constriction from the neck should be immediately removed, while the body is supported. The patient should be moved as little as possible, in case of spinal injury. The patient should be laid down, the airway opened and CPR performed if necessary.

How to Perform CPR

CPR (cardiopulmonary resuscitation) is an emergency procedure that combines chest compressions often with artificial ventilation in an effort to manually preserve intact brain function in a person who is in cardiac arrest. It involves chest compressions for adults 5-6cm deep and at a rate of 100-120 per minute, set to breathing ratios at 30 to 2. It alone is unlikely to restart the heart, its main purpose is to delay tissue damage and death, especially brain damage. An untrained person may deliver hands-only CPR.

     STEP 1: shake and stout
Keep calm. Check for danger. Check for response (gently shake the person and speak to them). Shout for help.

     STEP 2: check breathing and bleeding
Stop the bleeding. Check for breathing (chest movements, feeling of breath) for no more than 10 seconds. Do not confuse gaps with normal breathing.
If an unconscious person is breathing normally, put them in the recovery position and call emergency services.
If you are not sure, act as if the breathing is not normal.
If breathing is not normal, open the airway. Support the head, gently tilt it back and lift the chin. Clean the mouth of foreign objects. Do not remove the helmet.

     STEP 3: call emergency services
If there are more people, ask them to assist you.

     STEP 4: give 30 chest compressions
Put the heel of one hand in the centre of the chest. Place your other hand on the top of the first and interlock your fingers. With straight arms, push the breastbone down firmly and smoothly and release. Repeat 30 times, 2 pushes per second.

STEP 5: give 2 rescue breaths
Give mouth to mouth. Hold the nose closed. The patients chest should rise and fall. This should take no longer than 5 seconds. Check for breathing.

     STEP 6: repeat until help arrives
Keep going until professional help arrives or the patient starts to show signs of regaining consciousness.

Other Conditions

A medical emergency is an acute injury or illness that poses an immediate risk to a person's life or health. These emergencies require assistance dependent of the severity of the condition.
          Altitude sickness can cause potentially fatal swelling of the brain or lungs. Symptoms occur hours after ascent and include headache, fatigue, sleep disturbance and dizziness, but can become much worse. The most serious symptoms arise from edema, HAPE is the high altitude pulmonary edema. This condition can be prevented and the only reliable treatment is to descend.
           Anaphylaxis, a serious allergic reaction, occurs rarely with stings and insect bites. Symptoms include swelling, breathing difficulties, shortness of breath, vomiting, low blood pressure and a rash.  Swelling can be life-threatening and urgent medical attention is required. Carrying an epinephrine autoinjection and identification regarding the condition is recommended in people with a history of this condition.
          A bone fracture is a condition in which there is a partial or complete break in the bone, severe cases include bone broken into several pieces. Symptoms include pain, deformity, swelling and bruising, loss of function, inability to move, and in open fractures, bone protruding from the skin. Treatment should involve immobilization, a splint can by applied to a broken limb, the wound should be cleaned and protected by sterile dressing. Later treatment can involve surgical corrections.
          A burn is a type of injury to tissues caused by heat, cold, electricity, chemicals, friction or radiation. Treatment depends on the severity of the burn, major burns require prolonged treatment in specialized burn centres. Cooling with water may help pain and decrease damage, a sterile bandage can be applied. Clothing stuck to the skin should not be removed and ice and creams should not be applied.
               A first-degree burns are superficial and affect only the top skin layers, they appear red and hurt about three days. A second-degree burn extends to underlying skin layers, blisters are frequently present and very painful, they can heal up to eight weeks and scarring may occur. A third-degree burn is a full-thickness that extends to all layers of the skin, there is often no pain and the area is stiff. A fourth-degree burn involves injury to deeper tissues, it is often black and leads to loss of the burned part.
               Scalding is a form of thermal burn resulting from heated fluids. Most scalds are considered first or second degree burns, but prolonged contact can cause more damage.
          Cardiac arrest is a sudden loss of blood flow resulting from the failure of the heart to pump effectively. Symptoms include loss of consciousness, abnormal breathing, chest pain and nausea. If not treated with CPR and AED (automated external defibrillator) within minutes, it typically leads to death.
          Heart attack, or myocardial infarction, occurs when blood flow decreases or stops to a part of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort to the left, an also shortness of breath, nausea, feeling faint, cold sweat and feeling tired. Treatment is time-critical and the patient should go to a hospital in under an hour. Aspirin and nitroglycerin can be given to the patient, supplemental oxygen can also help.
          Heat stroke, also called hyperthermia, is a condition where the body temperature is elevated due to failed thermoregulation. Symptoms can include heavy sweating, rapid breathing, confusion and a fast and weak pulse. A mild condition can be treated by increased water consumption and resting in a cool place. In a more serious condition, active cooling methods are used. When body temperature reached 40°C, treatment is a hospital is required.
          Hypothermia is defined as a body core temperature below 35°C. Symptoms of mild hypothermia include shivering and confusion and it is usually treated by warming the patient. In severe hypothermia, people often remove their clothes because they are confused and feel warm, this is called paradoxical undressing. Patients are rewarmed to 32°C and resuscitated, survival is possible and especially children are known to recover.
          A joint dislocation, also called luxation, occurs when there is an abnormal separation in the joint, often caused by sudden trauma. It can cause damage to the ligaments, tendons, muscles and nerves, symptoms include pain, joint instability and deformity, bruising, stiffness and difficulty moving. Reduction should be performed only by trained professionals, an untrained person can substantially worsen the injury. It is important that the joint is x-rayed and reduced as soon as possible and they are usually held in place by a splint or bandage.
          Poisoning is a condition in which the patient becomes chemically harmed by a toxic substance or venom. Symptoms develop in close relation to the degree of exposure. Chronic poisoning is long-term repeated or continuous exposure to a poison, the patient gradually becomes ill. With swallowed poison, the remaining poison has to be removed from the mouth, but vomiting must not be induced. With skin poisoning, contaminated clothing should be removed and the skin needs to be properly rinsed, eye poisoning should be also carefully flushed out. If the poison is inhaled, the patient should be brought to fresh air.
           A stroke is a medical condition in which poor blood flow to the brain results in cell death. There are two types, ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Symptoms may include inability to move or feel on one side of the body, problems understanding or speaking, dizziness and loss of vision to one side. Emergency services should be called immediately. The patient should be kept safe and calm and should not eat or drink anything.

          Nosebleeds, also called epitaxis, happen when bloodvessels in the nose break. Patients should sit upright and put pressure on the nose, lean forward and put a cold towel on the back of the neck. If the bleeding does not stop in 20 minutes, medical attention is necessary.

           Frostbite is a skin injury that happens when exposed to low temperatures. It is common for fingers, toes, ears, cheeks and the nose. The skin turns white or blue and there may be swelling and blistering. Treatment is by rewarming by warm water or body contact and is often painful. Surgery is sometimes necessary for deep frostbite and there is a risk of amputation.

First Aid Vocabulary

Updated: 20.01.2021

First Aid Vocabulary

accident - nehoda
apply - aplikovat

asphyxiation - dušení

arterial bleeding - tepenné krvácení
assess - zhodnotit, stanovit

bleed - krvácet

bleeding - krvácení
blister - puchýř

blood - krev
blood loss - ztráta krve
blow - foukat
breathing - dýchání

bruise - modřina

burn - popálenina, popálit
bystander - přihlížející, okolostojící, svědek

(plaster) cast - sádra
casualty - oběť, zraněný
casualties - ztráty na životech
check / recheck - zkontrolovat / překontrolovat

chest compressions - masáž srdce, stlačení hrudníku
choke - dusit se
compression - stlačení

concussion - otřes mozku

CPR (cardiopulmonary resuscitation) - kardiopulmonární resuscitace

cut - řezná rána, pořezat se
dirt - špína

disinfection - desinfekce

dislocation - vymknutí, vykloubení
dressing - obvaz, krytí
drown - utopit se
emergency - stav nouze, mimořádná událost, naléhavý případ

emergency services - složky záchranného systému
faint - omdlít
feature - charakteristický znak
firm / firmly - pevný / pevně
first aid - první pomoc
first aid giver - osoba poskytující první pomoc
foreign body - cizí těleso

hurt - bolet, ublížit se
immerse - ponořit
immobilize - znehybnit

injure - zranit se
injury - zranění
interlock - propojit
lightheaded - cítit závrať
loosen - uvolnit
maintain - zachovat, udržet
make sure - ujistit se
moist - vlhký
mouth to mouth - dýchání z úst do úst
occur - přihodit se, vyskytnout se
ointment - mast
overcome - překonat
pad - vložka, vycpávka, polštář
pale - bledý
pinch - skřípnout, štípnout

plaster (cast) - sádra
poisoning - otrava
procedure - postup, procedura
provide - poskytnout
puncture - propíchnout
recovery - zotavení
recovery position - stabilizovaná poloha
remove - odstranit
repeat - opakovat

rescue breath - umělé dýchání
response - reakce, odezva
scald - opařit se, opařenina
seal - uzavřít
seek - hledat
seep - prosáknout
shape - tvar, podoba
snap - prasknout, křupnout

sprain - vymknout si
sterilize - sterilizovat, vydesinfikovat
sterile dressing - sterilní obvaz, krytí
sting - bodnití, štípnutí

strangling - škrcení
squeeze - zmáčknout
summon - přivolat, předvolat
suffocate - udusit se
support - podpořit, podložit
swab - vytřít tamponkem
swelling - otok, zduřenina
tenderness - citlivots na dotek
tilt - naklonit
treat - ošetřit
unconscious - v bezvědomí

venous bleeding - krvácení z žíly
victim - oběť

Human Body Summary

Updated: 21.04.2020

Human Body Summary

Parts of the body: head, neck, trunk (torso) and limbs (arms and legs)
Types of tissue: lining cells (epithelia), connective tissue, nervous tissue and muscle tissue
Organ systems: respiratory, digestive, cardiovascular, urinary, integumentary, skeletal and muscular, endocrine, lymphatic, nervous and reproductive
Other systems: immune, exocrine


Circulatory system: permits blood to circulate
          blood, blood vessels (arteries, veins, capillaries) and heart
Lymphatic system: returns filtered blood plasma as lymph, transports white blood cells and cells related to immunity response
          lymph, lymph nodes and vessels
Digestive and excretory system: digestion and absorption of food, metabolism
          gastrointestinal tract (mouth, oropharynx, esophagus, stomach, small and large intestines, and the anus) and accessory organs
Endocrine system: a chemical messenger via a system of hormones
          endocrine glands (pineal gland, pituitary gland, pancreas, ovaries or testes, thyroid gland and parathyroid gland, hypothalamus and adrenal glands)
Integumentary system: protects the body from damage, generates vitamin D
          skin, hair and nails
Muscular system: permits movement of the body, maintains posture and circulates blood
          skeletal, smooth and cardiac muscles
Skeletal system: internal framework of the human body, protects major organs
          206 bones, axial and appendicular skeleton
Nervous system: coordinates actions and sensory information
          CNS - central (brain and spinal cord) and PNS - peripheral (somatic, automatic and enteric)
Reproductive system: sexual reproduction
          male (sperm, penis, testicles, sperm ducts, prostate) and female (egg cell, uterus, ovaries, vagina, vulva)
Respiratory system: exchange of gasses
          upper (nose and mouth, nasal cavities and paranasal sinuses, pharynx and larynx) and lower (trachea, bronchi, alveoli, lungs) respiratory tract
Urinary system: eliminates waste
          kidneys, ureters, bladder, and urethra



Exocrine system: a system of hormones and glands
          salivary glands, sweat glands, ciliary, ceruminous lacrimal, meibomian, sebaceous, mucous and mammary glands
Immune system: protects against disease
          thymus, bone marrow, tonsils, lymph vessels and nodes



The human body is the structure of a human being. It contains trillions of cells, the fundamental units of life. The adult male body is about 60% water. The human body comprises of a head, neck, trunk, which includes the thorax and abdomen, and limbs, arms and hands, and legs and feet. The shape of a human body is determined  mainly by the skeleton, but also by the distribution of muscle and fat.
          The whole body is covered by the skin. There are five main senses, sight, hearing, smell, taste and touch. There are four main cavities, cranial, spinal, thoracic ans abdominopelvic, divided into abdominal and pelvic cavities.
          The head is the seat of the brain and several sense organs and it is supported by seven cervical vertebrae. It consists of the skull which encloses the brain and is covered by the scalp with hair and the face.
          The neck joins the head and the trunk, it supports the weight of the head, protects the spine and allows movement.
          The trunk, also called torso, is the central part of the body and houses many critical organs. The diaphragm divides the torso into the thoracic cavity and the abdominal cavity. The upper chest is protected by the rib cage.
          There are two upper and two lower extremities, also called limbs. The upper limb, the arm, is divided into the shoulder, the upper arm, the elbow, the forearm, the wrist and the hand, which is composed of the back and the palm, four fingers and a thumb. The leg is attached to the pelvic girdle. It is constituted of the hip, the thigh, the knee, the lower leg with the shin in the front and a calf at the back, the ankle and the foot with the instep, the sole, the arches and five toes.
     

The body consists of many different types of tissue, defined as cells that act with a specialized function. There are four main types of tissues, lining cells (epithelia), connective tissue, nervous tissue and muscle tissue. Endothelial cells line internal cavities including blood vessels and glands.
       
Organs are structured collections of cells with a specific function. An organ system is a group of organs that work together as a biological system to perform one or more functions. There are eleven distinct organ systems in human beings, respiratory, digestive, cardiovascular, urinary, integumentary, skeletal and muscular, endocrine, lymphatic, nervous and reproductive. The immune system is not an organ system. On the other hand, some organs are in more than one system.
          The circulatory system permits blood to circulate and transport nutrients, oxygen and carbon dioxide, hormones and blood cells from and to the cells to provide nourishment, stabilize temperature and pH and maintain homeostasis. The system comprises blood, heart and blood vessels and it is connected to the lymphatic system. Pulmonary circulation leads oxygen-poor blood under low pressure from the heart through the lungs where it is oxygenated. Systemic circulation is a loop through the rest of the body to provide oxygenated blood. Arteries are blood vessels that deliver oxygen-rich blood from the heart to the tissues of the body and veins carry deoxygenated blood from the tissues towards the heart. The heart is a hollow muscular organ which pumps oxygenated blood to the body and deoxygenated blood into the lungs.
          The lymphatic system returns filtered blood plasma as lymph. It comprises of lymph, lymph nodes and lymph vessels. Lymph is a clear fluid, it contains lymphocytes, a subtype of white blood cells.
          The immune system is a host defense system that protects against disease. To function properly, it must detect a wide variety of pathogens.  The key organs are thymus, bone marrow, spleen, tonsils, lymph vessels and nodes, adenoids, skin and liver.
          The function of the digestive system is digestion, absorption and metabolism. It is composed of the gastrointestinal tract and accessory organs. The gastrointestinal tract is made of the mouth, oropharynx, esophagus, stomach, small and large intestines, and the anus. The accessory organs are the liver, gallbladder and pancreas, their secretion flow into the small intestine and bring chemicals in food. Some parts of the digestive system are also part of the excretory system, a passive biological system that removes excess, unnecessary material from the body to help maintain homeostasis and prevent damage.
          The endocrine system is a chemical messenger system of hormones released by internal glands into the circulatory system. The major glands include the pineal gland, pituitary gland, pancreas, ovaries or testes, thyroid gland and parathyroid gland, hypothalamus and adrenal glands.
          The integumentary system includes skin, hair and nails. Its function is to protect the body from various kinds of damage, changes of temperature and dehydration, and it generates vitamin D through exposure to ultraviolet light.
           The exocrine system is a system of hormones and glands, where the glands secrete straight to a target site. It includes the salivary glands, sweat glands, ciliary, ceruminous lacrimal, meibomian, sebaceous, mucous and mammary glands. These glands work independently responding to the needs of the body.
          The muscular system is an organ system consisting of skeletal, smooth and cardiac muscles. It permits movement of the body, maintains posture and circulates blood throughout the body, it provides strength, balance, and heat.
          The skeletal system is the internal framework of the human body. It is composed of  around 206 bones by adulthood. The human skeleton can be divided into the axial skeleton and the appendicular skeleton. The axial skeleton consists of 80 bones and is formed by the vertebral column 32-34 bones), the rib cage (12 pair bones and the sternum), the skull and other (22 bones and 7 associated bones). The appendicular skeleton, which is attached to the axial skeleton, consists of 126 bones divided into six major regions, as it is formed by the shoulder girdle, the pelvic girdle and the bones of the upper and lower limbs.

          The nervous system is a highly complex part of the human body that coordinated its actions and sensory information by transmitting signals to and from its different parts. It consists of the central nervous system (CNS) and the peripheral nervous system (PNS).
          The reproductive system is a system of sex organs which work together for the purpose of sexual reproduction. The male reproductive system is a series of organs primarily located outside the body that have one function, to produce and deposit sperm. The main male sex organs are the penis and the testicles, the internal parts are the epididymis, sperm ducts and three glands, for example the prostate. The female reproductive system is a series of organs primarily located inside the body which have two functions, to produce egg cells and to protect and nourish the fetus until birth. The main female sex organs are the uterus, Fallopian tubes, ovaries and the vagina, the external part is the vulva.
          The respiratory system is associated with the exchange of gasses, oxygen and carbon dioxide, between the human body and the environment, and also between the tissue cells and the blood. These functions are achieved by ventilation, which consists of two acts, inspiration and expiration. The upper respiratory tract is formed by the nose and mouth, nasal cavities and paranasal sinuses, pharynx and larynx. The lower respiratory tract consists of the trachea, bronchi, bronchioles and the alveoli inside two lungs.

          The urinary system consists of the kidneys, ureters, bladder, and the urethra. It functions to eliminate waste from the body, regulate blood volume and blood pressure, control levels of electrolytes and metabolites, and regulate blood pH.

Human Body

Updated: 09.01.2020

Human Body

The human body is the structure of a human being. It is composed of many different types of cells that together create tissues and organ systems. They ensure homeostasis and the viability of the human body. Many systems and mechanisms interact in order to maintain homeostasis, with safe levels of substances such as sugar and oxygen in the blood.
          It body is composed of elements including hydrogen (9,5%), oxygen (65%), carbon (18,5%), calcium (1,5%) and phosphorus (1%). The main electrolytes outside cells are sodium and chlorides, whereas within cells it is potassium and other phosphates. Trace elements are less than 1% combined. The adult male body is about 60% water, a total water content of about 42 litres, which is made up of about 19 litres of extracellular fluid, including about 3,2 litres of blood plasma.

The human body comprises of a head, neck, trunk, which includes the thorax and abdomen, and limbs, arms and hands, and legs and feet. The shape of a human body is determined  mainly by the skeleton, but also by the distribution of muscle and fat. The study of the human body involves anatomy, physiology, histology and embryology. The body is studied by health professionals, physiologists, anatomists, but also by artists.
          The whole body is covered by the skin. There are five main senses, sight, hearing, smell, taste and touch. There are four main cavities, cranial, spinal, thoracic and abdominopelvic, divided into abdominal and pelvic cavities.
          The head is the seat of the brain and several sense organs and it is supported by seven cervical vertebrae. It consists of the skull which encloses the brain and is covered by the scalp with hair and the face. The skull supports the structures of the face and provides a protective cavity for the brain. It consists of the cranium and the mandible, the jawbone. The face is made up of the forehead and the temples, eyes, upper and lower lids and eyebrows, cheeks, nose, mouth with two lips, the oral cavity with the tongue and teeth, chin and ears. The face is crucial for human identity and can express many emotions.
          The neck joins the head and the trunk, it supports the weight of the head, protects the spine and allows movement. It contains cervical vertebrae, the trachea, the pharynx, the larynx, the thyroid gland and important blood vessels and nerves. The muscles of the neck bound two major neck triangles, anterior and posterior. The thyroid cartilage of the larynx forms a bulge in the middle of the neck called Adam's apple, which is more prominent in men.
          The trunk, also called torso, is the central part of the body and houses many critical organs. The diaphragm divides the torso into the thoracic cavity and the abdominal cavity. The main parts of the thorax are lungs within the pleural cavity, the heart, the trachea, and the esophagus. The upper chest is protected by the rib cage. On the chest there are nipples and, in women, breasts. Inside the abdominal cavity we can find the stomach, the liver, the gallbladder, the pancreas, the spleen, the kidneys, the urinary bladder, the small and large intestines, and the internal reproductive organs within the pelvic region. The back is the large area rising from the top of the buttocks to the back of the neck and the shoulders and the vertebral column, the spine, runs through its length.
          There are two upper and two lower extremities, also called limbs. The upper limb, the arm, is divided into the shoulder, the upper arm, the elbow, the forearm, the wrist and the hand, which is composed of the back and the palm, four fingers and a thumb. The leg is attached to the pelvic girdle. It is constituted of the hip, the thigh, the knee, the lower leg with the shin in the front and a calf at the back, the ankle and the foot with the instep, the sole, the arches and five toes.
       

Cells

The body contains trillions of cells (roughly 35 trillion), the fundamental unit of life. It is also host to about the same number of non-human cells and multicellular organisms which reside in the gastrointestinal tract and on the skin. Not all parts of the body are made from cells, they sit in an extracellular matrix that consists of bone and connective tissue, surrounded by extracellular fluids.
          Deoxyribonucleic acid (DNA) is a molecule composed of two chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth, and reproduction of all known organisms and many viruses. Ribonucleic acid (RNA) is a polymeric molecule essential in coding, decoding, regulation and expression of genes. DNA and RNA, along with lipids, proteins and carbohydrates, constitute major macromolecules essential for all known life forms. They are assembled as a chain of nucleotides.
          Cells in the body function because of DNA, which sits within the nucleus of a cell, where its parts are copied and sent to the body of the cell via RNA to create proteins. However, not all cells have DNA, some cells, such as mature red blood cells, lose their nucleus as they mature.
          Stem cells are cells that can differentiate into other types of cells and can also divide in self-renewal to produce more stem cells. There are two broad types, embryotic stem cells and adult stem cells. Adult stem cells are frequently used in various therapies, for example bone marrow transplantation. Progenitor cells have a tendency to differentiate into specific types of cells, but are already more specific, they have target cells. They can divide only a limited number of times. In adult organisms, stem cells and progenitor cells act as a repair system.

Tissues

The body consists of many different types of tissue, defined as cells that act with a specialized function. There are four main types of tissues, lining cells (epithelia), connective tissue, nervous tissue and muscle tissue. Endothelial cells line internal cavities including blood vessels and glands.
          Epithelial tissue, lining cells cover surfaces, regulate what can or cannot pass through them, protect internal structures and function as sensory surfaces.
          Muscle tissue form the active contractile tissue, they function to produce force and cause motion. They have three distinct categories, smooth muscle (visceral) in the inner linings of organs, skeletal muscle typically attached to bones and cardiac muscle of the heart.
           Nervous cells, neural tissue, are cells comprising the central and peripheral nervous system. They form the brain sn spinal cord and cranial and spinal nerves.
           Connective cells are fibrous tissues made up of cells separated by an extracellulal matrix. They can be liquid or rigid and they give shape to organs and hold them in place. They are divided into three types, fibrous, skeletal and fluid.

Organs and Systems

Organs are structures collections of cells with a specific function. Many organs reside within cavities, such as the abdomen and pleura, which contains the lungs.
          There is no universally standard definition of what constitutes and organ. Therefore, the number of organs varies depending on various definitions.
          An organ system is a group of organs that work together as a biological system to perform one or more functions. Each organ does a particular job and is made up of distinct tissues.
          There are eleven distinct organ systems in human beings, respiratory, digestive, cardiovascular, urinary, integumentary, skeletal and muscular, endocrine, lymphatic, nervous and reproductive. There are other systems in the body, but not organ systems. The immune system is not an organ system. On the other hand, some organs are in more than one system.

Circulatory (Cardiovascular) System

red blood cell, platelet and white blood cell

This organ system permits blood to circulate and transport nutrients, oxygen and carbon dioxide, hormones and blood cells from and to the cells to provide nourishment, stabilize temperature and pH and maintain homeostasis. The system comprises blood, heart and blood vessels and it is connected to the lymphatic system. It is a closed system which has two components, the systemic circulation and the pulmonary circulation.
          Blood is a fluid consisting of plasma, red blood cells, white blood cells and platelets that is circulated by the heart through the system. The movement of blood around the body is called circulation, it takes less than a minute to pump blood to every cell in the body. An average adult contains roughly 4.7 to 5.7 litres of blood, which is about 7% of their weight.
          Plasma is about 55% of blood, it is a fluid that functions as the liquid medium for blood. It is straw-yellow and contains mostly water, but also proteins, glucose, clotting factors, electrolytes, hormones, carbon dioxide and oxygen. It is separated from the blood by spinning a tube of fresh blood containing an anticoaticoagulant in a centrifuge until the blood cells fall to the bottom of the tube.
          Red blood cells, erythrocytes, occupy about 45% of blood, they contain hemoglobin and distribute oxygen. They are marked by glycoproteins that define the different blood types, mainly the ABO and Rh antigen systems.
          White blood cells, leukocytes, are the cells of the immune system that are involved in protecting the body against infectious disease and foreign invaders.
          Platelets, thrombocytes, ale clotting cells, their function is to react to bleeding by clumping, they also contribute to homeostasis.
          Blood pressure is the pressure of circulating blood on the walls of blood vessels and it is one of the vital signs. Systolic pressure is the maximum during one heartbeat and diastolic pressure is the minimum in between two heartbeats. Normal resting blood pressure in an adult is 120/80mmHg. Traditionally, it was measured using auscultation with a mercury-tube sphygmomanometer, but today, semi-automated methods became common.
          Heart rate is the speed of the heartbeat measured by the number of contractions per minute. It can vary according to the body's physical need. The average heart rate is 60-100bpm, usually 70bpm.
          Pulmonary circulation leads oxygen-poor blood under low pressure from the heart through the lungs where it is oxygenated.
          Systemic circulation is a loop through the rest of the body to provide oxygenated blood.
          Arteries are blood vessels that deliver oxygen-rich blood from the heart to the tissues of the body. Each artery is a muscular tube lined with smooth tissue. The largest artery is the aorta, a massive, thick-walled and elastic artery which delivers blood and helps to maintain blood pressure. It branches into smaller arteries, arterioles and capillaries, small passages that merge to bring blood into the veins.
          Veins carry deoxygenated blood from the tissues towards the heart. They are less muscular and often closer to the skin. They are equipped with valves to prevent blood flowing in the reverse direction.
          The heart lies between the lungs, a little to the left of the middle of the chest. It is a hollow muscular organ which pumps oxygenated blood to the body and deoxygenated blood into the lungs. It consists of four chambers, separated by a septum into left and right halves, left and right atrium and left and right ventricle. There are valves between the atria and ventricles that prevent the backflow of blood. The right atrium is the upper chamber of the right side, deoxygenated blood is returned into it and passed into the right ventricle to be pumped through the pulmonary artery to the lungs for reoxygenation and removal of carbon dioxide. The left atrium receives newly oxygenated blood from the lungs and passes in to the strong left ventricle to be pumped through the aorta back into the body.
          Lungs receive oxygen-depleted blood from the heart and gas exchange occurs. The carbon dioxide is released from the blood and oxygen is absorbed instead.

Lymphatic System

This organ system returns filtered blood plasma as lymph. The system comprises of lymph, lymph nodes and lymph vessels. It is a opened system providing an accessory route for excess interstitial fluid to be returned to the blood. Its other function is in the adaptive immune system and absorption of fatty acids and fats.
          Lymph is a clear fluid, essentially recycled excess blood plasma. It is very similar to blood plasma and it contains lymphocytes, a subtype of white blood cells. The passage of lymph takes much longer than that of blood.

Immune System

The immune system is a host defense system that protects against disease. To function properly, it must detect a wide variety of pathogens.
          The innate immune system recruits immune cells to sites of infection, identifies and removes foreign substances and activates the adaptive immune system. It acts as a physical and chemical barrier to infectious agents, such as skin.
          The adaptive (acquired) immune system is composed of highly specialised systemic cells and processes to eliminate pathogens. Acquired immunity creates immunological memory after an initial response to a specific pathogen, which leads to enhanced response in the future. This is the basis of vaccination. Antigens are substances that elicit the acquired immune response and antibodies travel through the blood stream and bind to the foreign antigen causing it to inactivate.

The immune system includes primary lymphoid organs, secondary lymphatic tissues and other. The key organs are thymus, bone marrow, spleen, tonsils, lymph vessels and nodes, adenoids, skin and liver.
          White blood cells act like independent organisms. They identify and eliminate pathogens. There are five different types, lymphocytes are the main type of cell found in lymph.
          The tonsils are a set of lymphoid organs which play an important role in the immune system. They are the first line of defense against ingested or inhaled foreign pathogens. They are set in the aerodigestive tract and consist of palatine, lingual, tubal and adenoid tonsils.
          Bone marrow is found in the interior of bones and it produces red blood cells and lymphocytes.
          The thymus is a lymphoid gland between the lungs. Within it, the T cells, which are critical to the adaptive immune system, mature.

Digestive and Excretory System

The function of the digestive system is digestion, absorption and metabolism. Peristalsis is the rhythmic contraction of muscles that begins in the esophagus and continues in the gastrointestinal tract.
          The digestion process involves the breakdown of food into smaller components and it takes 12 to 48 hours. There are two types of digestion, mechanical and chemical. Mechanical digestion changes large pieces into small pieces by chewing and solid food into liquid form. Chemical digestion begins in the mouth with the addition of the enzyme ptyalin to the food, also, saliva contains digestive enzymes called amylase and lingual lipase. Digestion continues with swallowing through the esophagus and then the additional digestive processes in the stomach. Food is broken down by mixing with gastric acid and digestion is complete when nutrients have been reduced ti their simplest form.
          Digested food is able to pass through the gastrointestinal tract. Absorption of most of the nutrients occurs in small intestine, the majority in the jejunum. Absorption of water happens in the large intestine and the remaining waste material is defecated.
          Metabolism is the chemical process by which the body uses nutrients for energy and the building of body tissue. Two processes are involved in metabolism, anabolism and catabolism. Anabolism is the building, repairing and maintaining of tissue, it is a constructive process used to synthetize complex molecules from precursors. On the other hand, catabolism is the breaking down of tissues and excretion of the byproducts, large molecules are broken down to provide energy.

The digestive system is composed of the gastrointestinal tract and accessory organs. The gastrointestinal tract is made of the mouth, oropharynx, esophagus, stomach, small and large intestines, and the anus. The accessory organs are the liver, gallbladder and pancreas, their secretion flow into the small intestine and bring chemicals in food.
          Some parts of the digestive system are also part of the excretory system, including the large intestine. The excretory system is a passive biological system that removes excess, unnecessary material from the body to help maintain homeostasis and prevent damage. Its function is to eliminate waste and drain the body of used components.
          The mouth is the first part of the upper gastrointestinal tract and it begins digestion. The oral cavity is lined with a mucous membrane which secrets mucus which contains the glycoprotein mucin. Within the mouth, there are the tongue, teeth and three pairs of salivary glands which produce saliva to moisten and soften food. The tongue is a muscular sensory organ with taste buds and teeth are complex structures made of bone-like material called dentin covered by enamel. The roof of the mouth is called the palate and it separates the oral and the nasal cavities. The front part is called hard palate and the backpart is the soft palate, made of muscle and connective tissue which allows swallowing. There are also the uvula, the tonsils, the palatine arch and the epiglottis, a flap elastic cartilage attached to the entrance of the larynx to prevent food from going into the trachea.
          The pharynx is the common pathway of food and air, it is the part of the throat behind the nasal cavity. It is made of three parts, nasopharynx, oropharynx and laryngopharynx. When its muscular tissue contracts during swallowing, food and fluid move into the esephagus.
          The esophagus is a muscular tube about 25cm long and its peristalsis moves food into the stomach. At rest it is closed at both ends, the upper esophageal sphincter is triggered by the swallowing reflex.
          The diaphragm is a muscular separation of the thoracic cavity and the abdominal cavity. It anchors the liver and is attached to the duodenum.
          The stomach is a hollow, J-shaped organ composed of three parts, the fundus, the body and the pylorus. Stomach muscles contraction mix food with gastric secretion to form chyme after an hour or two. The stomach also produces hormones gastrin and enterogastrone and gastric juices that help in digestion. Gastric acid mainly contains hydrochloric acid and sodium chloride and the enzyme pepsin begins the digestion of proteins, the walls of the stomach are protected by a mucus layer. The stomach can expand to hold about one lite of food.
          The lower gastrointestinal tracts begins with the small intestine and ends at the anus. The small intestine is divided into the duodenum, jejunum and ileum and most food is digested here. Its glands secrete digestive enzymes and hormones. In the duodenum, the acidic chyme is neutralised by an alkaline fluid mix and absorption begins. The jejunum is about 2,5m long and it specialises in absorption of nutrients and magnesium. The ileum is from 2 to 4m long and it absorbs vitamin B12, bile salts and other products of digestion.
          The cecum is a pouch marking the division between the small and the large intestine and it is also the part where the appendix is attached. The appendix is a blind-ended tube, it helps to maintain gut flora and it is an important part of the immune and lymphatic system.
          The large intestine, also called large bowel, is about 1,5m long and it begins at the cecum and consists of the colon and rectum. The passage of the digesting food is slower at the colon, it takes from 12 to 5 hours until it is removed by defecation. It serves to absorb water and fermentate digestible matter by the gut flora which it turned into feces. The rectum is the last section of the large intestine, it holds the formed feces awaiting elimination through the anus. The typical brown colour of mammal waste is due to bilirubin, a breakdown product of normal heme catabolism.

          The spleen is the largest lymphoid organ in the body, its function is to break down red and white blood cells. The product of this digestion is bilirubin, which is sent to the liver and secreted in the bile.
          The liver is the second largest organ on the right side under the diaphragm. It has many functions, it destroys toxic substances, helps with digesting carbohydrates and fats, synthetises proteins and cholesterol, stores glycogen, vitamins A, D, E, K, B12, iron, cholesterol and produces bile. Bile is a yellowish-green fluid that assembles and stores in the gallbladder, it helps in the absorption of vitamin K.
          The gallbladder is a hollow part of the biliary tract just beneath the liver. Bile, also called gall, is stored in this small organ before it is released into the small intestine to help break down fats.
          The pancreas lies on the left side under the stomach. It produces secretions and enzymes which change starches, fats and proteins into nutrients. It secrets insulin when the blood sugar becomes high, it moves glucose into the muscles for use as energy.

Endocrine System

The endocrine system is a chemical messenger system of hormones released by internal glands into the circulatory system. The system operates via feedback loops. The major glands include the pineal gland, pituitary gland, pancreas, ovaries or testes, thyroid gland and parathyroid gland, hypothalamus and adrenal glands.
          Hormones are signaling molecules produced by glands to target distant organs. Their function is to regulate physiology and behaviour, as a form of communication within the body. They bind to specific receptor proteins in the target cells resulting in a change in cell function.
          The thyroid gland is located at the front of the neck and it si shaped like a butterfly. The thyroid hormones increase the rate of cellular metabolism which can affect growth and development in children. The thyroid hormones can also affect the appetite, heartbeat, breathing, sexual function, sleep, blood flow and body temperature.
           There are also 4 to 6 parathyroid glands, found at the back of the thyroid glands. Their hormones cause an increase in blood calcium levels.
          The adrenal glands are located above the kidneys and produce a variety of hormones, including adrenaline and various steroids. It controls the behaviour during crisis and emotional situations, stimulates the heart and metabolic processes.
          The pancreas is located in the abdomen, below and behind the stomach, it has both an endocrine and an exocrine function. It releases insulin, glucagon and other hormones into the blood, which influences sugar levels. Also, it secrets pancreatic juice into the duodenum.
          The pineal gland, also called conarium, is located in the brain and it is shaped like a pine cone. It primarily releases melatonin which influences daily rhythms and modulates sleep patterns.
          The hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions. It synthetizes and secretes certain neurohormones, such as dopamine, oxytocin and vasopressin, that stimulate or inhibit the secretion of hormones from the pituitary gland. It controls hunger and thirst, body temperature, attachment behaviour, fatigue and sleep.
          The pituitary gland, also called hypophysis, is a pea-sized gland located in the brain. It secretes hormones which help to control growth, blood pressure, body temperature, pain control, energy management, sex organs, thyroid glands and metabolism.
          The gonad, also called sex glands, are mixed glands that produce sex cells gametes and sex hormones. Female reproductive cells are the egg cells produced by the ovaries and they produce estrogens and progesterone to stimulate maturation and establish the menstrual cycle. Male reproductive cells are called sperm and produced by the testes which produce testosterone.

Integumentary and Exocrine System

The integumentary system comprises of the skin and it includes skin, hair and nails. Its function is to protect the body from various kinds of damage, changes of temperature and dehydration, and it generates vitamin D through exposure to ultraviolet light.
           The skin is the larges organ of the body, it accounts for about 12 to 15% of total body weight and covers from 1,5 to 2m² of surface area. It is composed of at least two major layers of tissue, the epidermis and dermis.
          The epidermis is the outermost layer, providing the initial barrier to the external environment. It gives colour to the skin, it does not contain blood vessels and it consists of keratinized stratified squamous epithelium. The protein keratin also stiffens epidermal tissue to form nails which grow from the nail matrix at an average of 1mm per week. The deepest level of epidermis also contains nerve endings, it is separated from the dermis by the basement membrane.
          The dermis is the middle layer of skin, it comprises two sections, the papillary and reticular layers. It contains connective tissues, vessels, glands, follicles, hair roots. sensory nerve endings, and muscular tissue. Its function is to give elasticity to the integument while resisting distortions. The deepest layer, the hypodermis, is primarily made up of adipose tissue. Substantial collagen bundles anchor the dermis to the hypodermis in a way that permits most areas of the skin to move freely over the deeper tissue layers.
          Hair is a protein filament that grows from follicles found in the dermis and only mammals have it. Each strand of hair is made up of the medulla, cortex and cuticle. The medulla is not always present, it is an open, unstructured region. The cortex is the highly structural and organized source of mechanical strength and water uptake, it contains melanin. The shape of hair depends on the shape of the follicle and the cortex and the colour depends on the type of melanin, eumelanin or pheomelanin. The diameter of human hair varies from 0,017 to 0,18mm.
          The hypodermis, also called  the subcutaneous layer, is the layer beneath the skin. It is attached to the skin by collagen and elastin fibres and it is composed of adipocytes specialized in accumulating and storing fats. It acts as an energy reserve, the fats can be put back into circulation during intense effort or when a lack of energy occurs. It also participates in thermoregulation.

The exocrine system is a system of hormones and glands, where the glands secrete straight to a target site. It includes the salivary glands, sweat glands, ciliary, ceruminous lacrimal, meibomian, sebaceous, mucous and mammary glands. These glands work independently responding to the needs of the body.
          Exocrine glands contain a glandular portion and a duct portion the structures of which can be used to classify the gland. They are named based on how their products are secreted, by merocrine, apocrine or holocrine secretion.
          Sweat glands, also known as sudoriferous or sudoriparous, are small tubular structures of the skin that produce sweat. Eccrine sweat glands are distributed almost all over the body, most densely in palms and soles, and they function as a cooling mechanism with a water-based secretion. Apocrine sweat glands are mostly limited to the armpits and perineal area. Modified appocrine glands form ceruminous, mammary and ciliary glands.
          Ceruminous glands are located in the external auditory canal where they produce cerumen, simply called earwax, by mixing their secretion with sebum and dead epidermal cells.
          Mammary glands produce milk to feed young offspring, they are arranged in organs such as breasts. Lactation is the secretion of milk and is stimulated by hormones, with humans only females can lactate. The female breast consists of subcutaneous fat which covers and envelops a network of ducts that converge on the nipple.
          Ciliary glands, also called Moll's glands, are found on the margin of the eyelid and they secrete sebum that keeps lashes supple.
          Lacrimal glands are paired, almond-shaped glands located in the eyes. They secrete the aqueous layer of the tear film and produce tears.
          Sebaceous glands are located in the skin that opens into a hair follicle. They secrete an oily or waxy matter, called sebum, which lubricates the hair and skin. In humans, they occur mainly on the face and scalp, but there are no glands in the palms and soles.
          Meibomian glands, also called tarsal glands, are a type of sebaceous glands in the eyes. They produce meibum, an oily substance that prevents tears spilling.
          Mucous glands, called muciparous glands, are found in several parts of the body. They produce mucus, a polymer, a slippery aqueous secretion that serves to protect epithelial cells. Most of the mucus is produced in the gastrointestinal tract.
          Salivary glands are three paired major glands that produce saliva. This benefits the oral cavity and health in general because it provides protection, helps digestion and dissolves solid particles which can then enter the taste buds.

Musculoskeletal System

The muscular system is an organ system consisting of skeletal, smooth and cardiac muscles. It permits movement of the body, maintains posture and circulates blood throughout the body, it provides strength, balance, and heat. Some muscles are controlled by the nervous system and some are completely autonomous. Striated muscle tissue is a tissue that features repeating functional units called sarcomes, they are the basic building block. There are two types of striated tissue, cardiac and skeletal muscle tissue.
          Skeletal muscles are composed of muscle fibers called myocytes, which are composed of myofibrils, which are composed of sarcomes. Upon stimulation by an action potential, skeletal muscles perform a coordinated contraction by shortening each sarcome. Within the sarcome, actin and myosin fibres overlap in a contractile motion towards each other. This process consumes large amounts of adenosine triphosphate ATP, the energy source of the sell. When ATP is used, it becomes adenosine diphosphate ADP. Muscle tissue also contains a stored supply of a fast acting recharge chemical, creatine phosphate. Calcium ions are also required for each cycle of sarcome. There are approximately 639 skeletal muscles in the human body.
          At rest, the body produces the majority of its ATP aerobically in the mitochondria without producing lactic acid or other fatiguing byproducts. During exercise, the method changes to anaerobic pathways, such as the use of creatine phosphate and the phosphagen system of anaerobic glycolysis. This produces ATP much faster, but produces significant amounts of lactic acid which renders high-intensity exercise unsustainable for a longer time.
          Cardiac muscles, heart muscle tissue, have muscle fibres laterally connected to each other. Their movement is involuntary and they are controlled by the autonomic nervous system. The myocardium forms a thick middle layer between the outer layer of the heart wall, the epicardium, and the inner layer, the endocardium. It is composed by cells joined together by intercalated discs, encased by collagen fibres and other substances that form the extracellular matrix.
          Smooth muscles are controlled directly by the autonomic nervous system and are involuntary. They are divided into two groups, the unitary, single-unit, and multiunit smooth muscle. Within single-unit cells, the whole bundle or sheet contracts as a syncytium. Smooth muscles are found in the walls of hollow organs and in the walls of the passageways. Smooth muscle cells have a fusiform shape and can tense and relax, they demonstrate greater elasticity and function within a larger length-tension curve than striated muscle.
          Fascia are fibrous connective tissue, primarily collagen fibres oriented in a wavy pattern parallel to the direction of pull. They connect or separate, stabilize and enclose muscles to other muscles or other internal organs.

The skeletal system is the internal framework of the human body. It is composed of around 270 bones at birth, which decreases to around 206 bones by adulthood, after some bones are fused together. The bone mass in the skeleton reaches maximum density around age 21. The human skeleton can be divided into the axial skeleton and the appendicular skeleton. It performs six major functions, support, movement, protection, production of blood cells, storage of minerals and endocrine regulation. It is not as sexually dimorphic as that of many other primate species, but subtle differences between the sexes exist. Unlike most primates, human males do not have penile bones.
          The skeleton is the site of haematopoiesis, the development of blood cells that takes place in the bone marrow. The bone marrow is a semi-solid tissue composed of hematopoietic cells, marrow adipose tissue and supportive stromal cells. It produces approximately 500 billion blood cells every day in the heads of long bones.
          The axial skeleton consists of 80 bones and is formed by the vertebral column 32-34 bones), the rib cage (12 pair bones and the sternum), the skull and other (22 bones and 7 associated bones).
          The skull consists of the cranium and the facial bones. The cranial vault holds and protects the brain, it is formed from eight plate-shaped bones which fit together. There are 14 facial bones, including the jaw, called mandible, the upper jaw, called the maxilla, and the cheek and nasal bones. The only bone that remains separate from the rest is the mandible.
          The rib cage is composed of 12 pairs of ribs and the sternum, a total of 25 bones. It protects vital organs, such as the heart and lungs. The upper seven pairs are true ribs, they attach to the sternum. The eighth to tenth ribs have non-costal cartilage which connects them to the ribs above. The last two are called floating ribs, because they are not attached.
           The vertebral column consists of five parts, 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, 5 sacral vertebrae and 4 coccygeal vertebrae .At birth the majority of humans have 33 separate vertebrae. However, during normal development, several vertebrae fuse together, leaving a total of 24 vertebrae, the sacrum and the coccyx in most cases. The two lowest verterbrae, the sacrum and the coccyx, are single bones made up of several smaller bones fused together, they are simply called the sacral bone.
          The appendicular skeleton, which is attached to the axial skeleton, consists of 126 bones divided into six major regions, as it is formed by the shoulder girdle, the pelvic girdle and the bones of the upper and lower limbs. Their function is to make locomotion possible, they form from cartilage by the process of endochondral ossification. These bones are not fused and allow a much greater range of motion.
          The shoulder girdles are four bones, they consist of the left and right clavicle and scapula.
          The arms and forearms consist of sic bones, left and right humerus of the arm, the ulna and radius of the forearm.
          The hands consist of 54 bones, 16 left and right carpals (wrists), 10 metacarpals, 10 proximal phalanges, 8 intermediate phalanges and 10 distal phalanges.
          The pelvis consists of two bones, the left and right hip bone.
          The legs consist of eight bones, left and right femur of the thigh, two patella (knees), left and right tibia and fibula of the leg.
          The feet and ankles consist of 52 bones, 14 left and right tarsals (ankles), 10 metatersals, 10 phalanges, 8 intermediate phalanges and 10 distal phalanges.
          Joints, also called articulations, are the connection made between bones, they allow different degrees and types of movement. Some joints are self-lubricating and almost frictionless, like the knee or elbow. Other joints permit very little movement. The connection between tooth and the jawbone is also called a joint, a fibrous joint known as a gomphosis.
          Ligaments are fibrous connect tissue that connect bones to form joints. They are a band of dense regular connective tissue bundles made of collagenous fibres. They are viscoelastic, they gradually strain under tension and then return to their original shape.
          Tendons, also called sinew, are a tough band of fibrous connective tissue that connect muscle to bone and is capable of withstanding tension. They are made of collagen fibres parallel to each other.
          Cartilage is a resilient and smooth elastic tissue, a rubber-like padding that covers and protects the ends of long bones at the joints. It is a structural component of the rib cage, the ear and nose and many other. The matrix of cartilage is made up of glycosaminoglycans, proteoglycans, collagen fibres and sometimes elastin.

Nervous System

The nervous system is a highly complex part of the human body that coordinated its actions and sensory information by transmitting signals to and from its different parts. It detects environmental changes and works with other systems to respond to such events. It consists of the central nervous system (CNS) and the peripheral nervous system (PNS).
          Nerves that transmit signals from the brain are called motor or efferent, while those that transmit information from the body to the CNS are called sensory or afferent. The nerve cell is called a neuron, they have special structures that allow them to send signals rapidly and precisely to other cells. They send these signals in the form of electrochemical waves travelling along thin fibers called axons, which cause chemicals called neurotransmitters to be released at junctions called synapses. The connections between neurons can form neural pathways, neural circuits and larger networks that generate the perception of the world and determine behaviour.
          Gray matter consists of neuronal cell bodies, neuropil (dendrites and myelinated and unmyelinated axons), glial cells, synapses and capillaries. White matter consists of axons and oligodendrocytes, it contains relatively few cell bodies, it is composed chiefly of long-range myelinated axons called tracts. The colour difference arises mainly from the whiteness of myelin.
          Glial cells, simply called glia, are specialized cells that provide structural and metabolic support. The white matter contains more glia.
          The CNS consists of the brain and spinal cord. Nerves that exit from the cranium are called cranial nerves while those exiting the spinal cord are called spinal nerves. The CNS is composed of white and gray matter.
          The brain is encased in the skull and protected by the cranium. It consists of a cortex, composed of neuron-bodies constituting gray matter. There is also the subcortical gray matter making up a large number of different nuclei. The brain is the centre of the nervous system and the most complex organ which contains 14-16 billion neurons in the cerebral cortex and 55-70 billion neurons n the cerebellum.
          The spinal cord is continuous with the brain and lies caudally to the brain, it is protected by the vertebrae. It is a long, thin, tubular structure made up of nervous tissue, it extends from the brainstem to the lumbar region of the spine. It encloses the central canal of the spinal cord which contains cerebrospinal fluid. It is made of 31 segments, is around 44cm long and can be 6,4mm wide in the thoracic area. It is a center for coordinating many reflexes and contains reflex arcs that can independently control reflexes.
          The PNS consists mainly of nerves which are enclosed bundles of long fibres and axons that connect the CNS to every other part of the body. It is divided into three separate sybsystems, somatic, automatic and enteric. Somatic nerves mediate voluntary movement. The autonomic nervous system is further divided into the sympathetic and parasympathetic systems. The sympathetic system is activated in cases of emergencies to mobilize energy, while the parasympathetic system is activated in a relaxed state. The enteric system functions to control the gastrointestinal system. Both autonomic and enteric systems function involuntarily.

Reproductive System

The reproductive system, genital system, is a system of sex organs which work together for the purpose of sexual reproduction. The sexes of differentiated species have often significant differences between males and females. Humans have a high level of sexual differentiation, in addition to differences in nearly every reproductive organ, there are numerous differences in typical secondary sex characteristics. These allow for the combination of genetic material between two individuals, which allows for the possibility of greater genetic fitness of the offspring.
          A gamete is a haploid cells that fuses with another haploid cell during fertilization in organisms that sexually reproduce. The female gamete is a larger cell called ovum and the male gamete is a smaller cell called sperm.
          Human reproduction involves internal fertilization by sexual intercourse. In this process, the male inserts his penis into the female's vagina and ejaculates semen, which contains sperm. A small portion of the sperm pass through the cervix into the uterus and then into the Fallopian tubes for fertilization of the ovum. Only one sperm is required to fertilize the ovum, which then turns into a diploid zygote, travels out of the Fallopian tube and into the uterus, where it implants in the uterine wall.
          Pregnancy, also called gestation, is the time during which one or more offspring develops inside a woman. It continues for around nine months, about 38 weeks from fertilization, as the fetus develops. It is divided into three trimesters. At a certain point, pregnancy is concluded with childbirth, involving labor. During labor, the muscles of the uterus contract and the cervix dilates over the course of hours, and the baby passes out of the vagina.
          Human infants are nearly helpless and require high levels of parental care. They rely rely on their parents for comfort, cleanliness and food, which can be provided by breastfeeding, also called nursing, the feeding of a baby with milk from a woman's breast. The breast is prepared for lactation during pregnancy.

The male reproductive system is a series of organs primarily located outside the body that have one function, to produce and deposit sperm. The main male sex organs are the penis and the testicles, the internal parts are the epididymis, sperm ducts and three glands, for example the prostate.
          Testosterone is the primary male sex hormone and anabolic steroid. It plays a key role in the development of male reproductive tissues as well as promoting secondary sexual characteristics.
          Semen, also called seminal fluid, contains spermatozoa and other enzymes and fructose. Sperm is the male reproductive cell, it is able to move independently and it is much smaller than the female reproductive cell. On its own, it has a limited life span, but after fusion with an egg cell during fertilization, a new organism begins developing. It is haploid, so that its 23 chromosomes can join the 23 chromozomes of the egg to form a diploid cell.
          The penis is the male intromittent organ. It has a long shaft and an enlarged bulbous-shaped tip called the glans penis, which supports and is protected by the foreskin. When the male becomes sexually aroused, the penis becomes erect and ready for sexual activity. Erection occurs because sinuses within the erectile tissue of the penis become filled with blood. The arteries of the penis are dilated while the veins are compressed so that blood flows into the erectile cartilage under pressure. Ejaculation is the ejecting of semen from the penis, it is usually accompanied by orgasm. A series of muscular contractions delivers semen and usually, a refractory period succeeds the ejaculation. The penis also serves as the urinal duct.
          The scrotum is a pouch-like structure that hangs behind the penis, it holds and protects the testicles. Testicles or testis are a male reproductive gland which produces sperm by meiotic division within the seminiferous tubules, and to synthetise and secrete androgens, primarily testosterone, that regulate the male reproductive functions.
          The epididymis is a long whitish mass of tightly coiled tube. It connects a testicle to a vas deferens, where the sperm undergo maturation and are concentrated.
          The vas deferens, also known as sperm duct, is a thin tube that carries the spermatozoa from the epididymis to ejaculatory duct in anticipation of ejaculation.
          Three accessory glands provide fluids that lubricate the duct system and nourish the sperm cells. These are the seminal vesicles, the prostate gland and the bulbourethal glands. The seminal vesicles, or seminal glands, are a pair of simple tubular glands that secrete fluid that partly composes the semen. The prostate secretes a fluid which contributes to the volume of the semen which is slightly alkaline to help prolonging the lifespan of sperm.
       

The female reproductive system is a series of organs primarily located inside the body which have two functions, to produce egg cells and to protect and nourish the fetus until birth. The main female sex organs are the uterus, Fallopian tubes, ovaries and the vagina, the external part is the vulva.
          Estrogen is the primary female sex hormone, its three forms are estrone, estradiol and estriol, estetrol is produced during pregnancy. It is responsible for the development and regulation of the female reproductive system and secondary sex characteristics. Progestogens, also called gestagens, are steroid hormones, the most important is progesterone. Theie purpose is to maintain pregnancy.
          Menstruation, also known as period, is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. It stops occurring after menopause and during pregnancy.
          The egg cell, or ovum, is the female reproductive cell, typically not capable of active movement. It is 0,1mm big, the largest cell in the human body. On maturity, the follicle and the ovary's wall rapture, allowing the egg to escape and the Fallopian tube. This is called ovulation, it is periodic and it impacts directly to the length of a menstrual cycle.
          The ovaries are small, paired organs that produce egg cells and the secretion of hormones. At certain intervals, they release an ovum which passes through the Fallopian tube into the uterus.
          The Fallopian tubes, also called salpinges, are two tubes leading from the ovaries into the uterus.
          The uterus, of womb, accommodates the embryo which develops into a fetus. It provides mechanical protection, nutritional support, and waste removal for the developing baby. Contractions in its muscular wall are important in pushing out the baby. It produces vaginal and uterine secretions which help the transit of sperm to the Fallopian tubes. It contains three suspensory ligaments that help stabilize its position and limit its movement. It is pear-shaped and about 7,6cm long, 4,5cm broad and 3cm thick.
          The cervix is the neck of the uterus, the lower, narrow portion where it joins with the upper part of the vagina. It is cylindrical and conical in shape, usually 2-3cm long, and it protrudes through the upper anterior vaginal wall.
          The vagina is a fibromuscular canal leading from the outside of the body to the womb. It is elastic, it accommodates the penis during sexual intercourse and allows childbirth. The outer vaginal opening is partly covered by a membrane called hymen.
          The external sex organ is the vulva, which includes the mons pubis, labia, clitoris, urinary meatus, Bartholin's and Skene's vestibular glands and the vaginal opening. It protects the entrance to the vagina and it is supported by the pelvic floor muscles.

Respiratory System

The respiratory system is associated with the exchange of gasses, oxygen and carbon dioxide, between the human body and the environment, and also between the tissue cells and the blood. These functions are achieved by ventilation, which consists of two acts, inspiration, or taking air into the lungs because of the negative interpleural pressure created by enlarging of the thoracic cavity, and expiration, or exhaling air out of the lungs during which the muscles of respiration return to their former position.
          The structures concerned with ventilation are the upper and lower respiratory muscles, thorax and parts of nervous system. External respiration involves the exchange of oxygen and carbon dioxide in the capillaries and alveoli of the lungs. Internal respiration is the exchange of oxygen and carbon dioxide between cells and capillaries throughout the body. The normal rate of respiration varies with age, for an adult it is about 12 to 20 respirations per minute, for small children from 20 to 30.
          The upper respiratory tract is formed by the nose and mouth, nasal cavities and paranasal sinuses, pharynx and larynx.
          Air passes through the nose with two nostrils (nares) into the nasal cavities which are separated by the nasal septum. The air is warmed and moistened. Several small cavities known as paranasal sinuses are located in the skull near the nasal cavities, they are a group of four paired  spaces, ethmoidal, sphenoidal, maxillary and frontal.
          From the nasal cavities the air passes into the pharynx, or throat, which is separated into three parts, nasopharynx, oropharynx and laryngopharynx. The adenoids are located in the nasopharynx and the tonsils in the oropharynx. These two pairs of lymphoid tissue protect the body against infection. The pharynx provide a common passageway for air entering the larynx and food entering the esophagus. It is also important in vocalization.
          The epiglottis is a leaf-shaped closure, that prevents the entrance of food and fluid into the respiratory tract. It closes during swallowing.
          The larynx, also called the voice box, is a tube-like structure made up of muscles and a series of cartilage rings, the largest is called Adam's apple. It contains the vocal cords and manipulates pitch and volume of phonation. It also prevents foreign objects from entering the lungs by coughing and other reflexive actions.
          The vocal cords are folds of tissue that are key in creating sounds through vocalization. They vibrate, modulating the flow of air being expelled from the lungs during phonation.
          The lower respiratory tract consists of the trachea, bronchi, bronchioles and the alveoli inside two lungs.
          The trachea, also called windpipe, is a cartilaginous tube that connects the larynx and the lungs. Its function is to provide a passage for air to reach the lungs. It is also lined with cilia and the mucous membrane.
          The bronchi conduct air into the lungs. They are situated in the thoracic cavity which is lined with a moist membrane called the pleura. The right bronchus is shorter and more vertical. Each bronchus enters a lung where it branches like a tree to form many smaller tubes called bronchioles. These are smaller branches of the bronchial airways where the gas exchange occurs.
          The microscopic pulmonary alveolus, an air sac, is located at the end of each bronchiole. Across their membrane, oxygen is diffused and carbon dioxide released from the capillaries.
          The lungs are two large organs covered with visceral pleura and separated by the mediastinum. The right lung is divided into three lobes and the left into two lobes. Together they weigh about 1,3kg, the right one is bigger and heavies, because the left one shares space with the heart.

Urinary (Renal) System

The urinary system, also known as the renal system or urinary tract, consists of the kidneys, ureters, bladder, and the urethra. It functions to eliminate waste from the body, regulate blood volume and blood pressure, control levels of electrolytes and metabolites, and regulate blood pH. It is the drainage system for the eventual removal of urine. It is regulated by the endocrine system by hormones such as antidiuretic hormone, aldosterone, and parathyroid hormone, parathrin. Vasopressin regulates the retention of water by increasing water reabsorption in the nephrons.
          The female and male urinary system are very similar, differing only in the length of the urethra. The male urethra begins at the internal urethral orifice of the bladder, continues through the external urethral orifice, and then becomes prostatic, membranous, bulbar and penile urethra. The female urethra is much shorter, beginning at the bladder neck and terminating in the vaginal vestibule.
          Urination, also called voiding, is the ejection of urine from the urinary bladder to the outside of the body. In healthy humans, the process is under voluntary control.

          The kidneys have an extensive blood supply via the renal vein. Each kidney consists of functional units called nephrons. Its chief function is to regulate the concentration of water and soluble substances like sodium, reabsorbing what is needed and excreting the rest. Urine flows through the nephrons, through a system of converging tubes called collecting ducts, which then form minor calyces and major calyces, that join in the renal pelvis. Following filtration of blood and further processing, wastes in the form of urine exit the kidneys via the ureters. The kidneys filtrate about 180l per day ad reabsorb about 99% of this.
          The ureters are tubes made of smooth muscle fibres that propel urine towards the urinary bladder. They are usually 25-30cm long and around 3-4mm wide.
          The urinary bladder is a hollow muscular organ that stores and subsequently expels urine from the body by urination. A typical bladder will hold 300-500ml of urine before the urge to empty occurs, but it can hold considerably more.
          During urination, the urine s passed from the bladder through the urethra to the outside of the body. A healthy human produces 800-2000ml of urine every day.