Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
MBH - Health
OCR A level Biology F212
| Question | Answer |
|---|---|
| What is health? | A state of physical, mental and social wellbeing, which includes the absence of disease and infirmity. |
| What is disease? | A condition that impairs the normal functioning of an organism. |
| What is a parasite? | An organism that lives on or in another organism (the host) and causes damage to the organism. |
| What is a pathogen? | An organism that can cause damage to the organism it infects (the host). |
| What is malaria caused by? | Plasmodium, a eukaryotic, single-celled parasite. |
| How is malaria transmitted? | Via a vector – the female anopheles mosquito – which transfers the pathogen from one host to another when they feed on them. |
| What does plasmodium do? | Infects the liver and red blood cells, and disrupts the blood supply to major organs. |
| What is AIDS caused by? | The HIV virus. |
| Where does the HIV virus infect? What does it do? | White blood cells – it can only reproduce inside the cells of the infected organism. |
| What happens after HIV virus has reproduced? What does this lead to? | Kills WBCs as it leaves them, leading to AIDS. |
| What happens in AIDS? | Immune system deteriorates and eventually fails due to loss of white blood cells. Increases vulnerability to infections. |
| What are the three main ways in which HIV is transmitted? | Unprotected sexual intercourse, through infected bodily fluids, and from mother to fetus through placenta, breast milk or childbirth. |
| What is tuberculosis? | A lung disease caused by the bacterium Mycobacterium tuberculosis. |
| How does TB spread? | By droplet infection – when an uninfected person breathes in droplets of saliva or mucus containing the bacteria from an infected person. |
| Why are malaria, HIV and TB more common in sub-Saharan Africa and other developing countries? | Limited access to good healthcare, limited health education, limited equipment to reduce spread of infections, and overcrowded conditions. |
| How does the prevalence of malaria, HIV and TB slow down social and economic development? | Increase death rates, reduce productivity, and result in high healthcare costs. |
| Why is it important to study global distribution of diseases? | Finds who is at risk, predicts where epidemics may occur, important for medical research (e.g. how disease is spread) and allows organisations to provide aid to where it is needed most. |
| Define the term immune response? | The body’s reaction to a foreign antigen. |
| Define the term antigen? | Molecules (usually proteins or polysaccharides) found on the surface of cells. |
| Define the term antibody? | A protein, produced by a B-lymphocyte, which binds to a specific antigen. |
| What are primary defence systems? | Help prevent pathogens and parasites from entering it. |
| How does the skin act as a physical barrier? | Blocks pathogens from entering the body. |
| How does the skin act as a chemical barrier? | Produces chemicals that are antimicrobial and can lower pH, inhibiting the growth of pathogens. |
| What do mucous membranes protect? | Body openings that are exposed to the environment. |
| What do mucous membranes do? | Secrete mucus, a sticky substance that traps pathogens and contains antimicrobial enzymes. |
| What is a phagocyte? | A type of red blood cell that carries out phagocytosis (engulfment of pathogens). They are found in the blood and in tissues and are the first cells to respond to a pathogen inside the body. |
| How does a phagocyte engulf a pathogen? | Recognises the antigens on a pathogen, and moves its cytoplasm around the pathogen, engulfing it. |
| Where does the pathogen go once it has been engulfed? | Contained in phagocytic vacuole in cytoplasm of phagocyte. |
| How is the pathogen destroyed? | Lysosome fuses with phagocytic vacuole and enzymes break down the pathogen. |
| What does the phagocyte do once it has destroyed the pathogen? | Presents the pathogen’s antigens (sticks them on its surface to activate other immune cells). |
| What is a T lymphocyte? | A type of white blood cell with a surface covered in receptors. |
| What do the receptors on a T lymphocyte do? | Bind to complementary antigens presented by the pathogen and the phagocytes. |
| How are T lymphocytes different? | All have different receptors on their surface – so each will bind to a different complementary antigen. |
| What happens when the T lymphocyte binds to a complementary antigen? | Activates it to divide and differentiate into different types of T lymphocytes with different functions. |
| What different types of T lymphocyte can the T lymphocyte differentiate into? | Some which release substances to activate B lymphocytes; some attach to antigens on the pathogen and kill the cell; some become memory cells. |
| What are B lymphocytes? | Another type of white blood cells, covered in proteins called antibodies. |
| What do antibodies do? | Bind to antigens to form an antigen-antibody complex. |
| How do B lymphocytes differ? | They have different shaped antibodies on their surfaces. |
| What happens when the antibody on the surface of a B lymphocyte meets a complementary shaped antigen? | It binds to it. |
| What happens when the antibody on the surface of a B lymphocyte binds to a complementary antigen, along with substances released by T lymphocytes? | Activates the B lymphocyte. |
| What does an activated B lymphocyte do? | Divides by mitosis into plasma cells and memory cells. |
| What is cell signalling? | How cells communicate with each other. |
| How does cell signalling work? | A cell may release or present a substance that binds to the receptors on another cell, causing a response of some kind in the other cell. |
| How is cell signalling important in the immune response? | Helps to activate all the different types of white blood cells that are needed. |
| What is an example of cell signalling in the immune response? | T lymphocytes release substances that bind to receptors on B lymphocytes. This activates the B lymphocyte – the T lymphocytes are signalling to the B lymphocytes that there is a pathogen in the body. |
| What do plasma cells do? | Secrete loads of the antibody on the B lymphocyte (specific to the antigen) into the blood. |
| What do all these antibodies do? | Bind to the antigens on the surface of the pathogen to form lots of antigen-antibody complexes. |
| Variable region of antibody? | Form antigen binding sites. Shape of the variable region is complementary to a particular antigen. Variable regions differ between antibodies. |
| Hinge region of antibody? | Allows flexibility when the antibody binds to the antigen. |
| Constant region of antibody? | Allow binding to receptors on immune system cells e.g. phagocytes; is the same in all antibodies. |
| Disulfide bridges on antibodies? | Hold polypeptide chains together. |
| How do antibodies clear infections by agglutinating pathogens? | Each has two binding sites, so the pathogens can become clumped together. Phagocytes then bind to the antibodies and phagocytose a lot of pathogens all at once. |
| How do antibodies clear infections by neutralising toxins? | Antibodies bind to toxins produced by pathogens, preventing the toxins from affecting human cells (toxins are neutralised). Toxin-antibody complexes are also phagocytosed. |
| How do antibodies clear infections by preventing the pathogen binding to human cells? | When antibodies bind to antigens on pathogens, may block cell surface receptors that the pathogens need to bind to the host cells, so the pathogen can’t attach to / infect the host cells. |
| What are the differences between the primary and secondary immune responses? | Secondary is faster and stronger. |
| Why is the secondary immune response better than the first? | Memory T and B lymphocytes produced by the first infection remain in the blood, so they find the antigen and respond more rapidly to it. |
| What happens in active immunity? | Exposure to antigen, takes a while for protection to develop, protection is long term, memory cells are produced. |
| What happens in passive immunity? | No exposure to antigen, protection is immediate, protection is short term, no memory cells are produced. |
| What is natural active immunity? | When you become immune after catching a disease. |
| What is natural passive immunity? | When a baby becomes immune due to the antibodies it receives from its mother, through the placenta and in breast milk. |
| What is artificial active immunity? | When you become immune after being given a vaccination containing a harmless dose of antigen. |
| What is artificial passive immunity? | When you become immune after being injected with antibodies from somebody else. |
| What do vaccinations always contain? In what form? | Antigens. May be free or attached to dead or attenuated pathogen. |
| How do vaccinations control disease in the vaccinated person? | Have memory cells, so immune response happens quickly, before symptoms. |
| What is herd immunity? | Where so many people in a population are immune because they have been vaccinated that the disease becomes very rare, so even non-vaccinated people are unlikely to get the disease. |
| Why is it difficult to vaccinate against influenza? | New strains develop each year, so new vaccinations have to be made against these strains. |
| How do WHO deal with the ever changing influenza strains? | Develop new vaccinations each year and test against samples of the different strains, to judge which vaccination is the most effective against recently circulating viruses. |
| How are many medicinal drugs manufactured? | Using natural compounds found in plants, animals or microorganisms. |
| Why is it important to conserve organisms which are not currently used to make medicinal drugs? | Not all organisms have been investigated, so they might be the source of a drug which is still to be found. |
| What is atherosclerosis? | The hardening of arteries due to the formation of atheromas. |
| How are atheromas formed? | Damage occurs to lining of artery. White blood cells move into the area. More white blood cells, lipids and connective tissue build up to form a fibrous plaque in the wall. |
| What effect does an atheroma have on an artery? | Partially blocks lumen of artery and restricts blood flow. |
| How does smoking cigarettes increase the chance of atheromas? | Nicotine increases blood pressure, which can cause damage to the arteries. |
| What is coronary heart disease? | When the coronary arteries have a lot of atheromas in them, causing a lack of blood flow to the heart. |
| How does carbon monoxide increase CHD risk? | Irreversibly combines with Hb, reducing the amount of oxygen transported in the blood, which reduces the amount of oxygen available to the heart tissue. |
| How does nicotine increase the risk from CHD? | Makes platelets sticky, increasing the chance of a blood clot. If a blood clot happens in coronary arteries, could lead to a heart attack. |
| What is a stroke? | Rapid loss of brain function due to a disruption in the blood supply to the brain. |
| What is the cause of a stroke? | Can be caused by a blood clot in the artery leading to the brain, reducing the amount of blood and therefore oxygen which can reach the brain. |
| How does nicotine increase the chance of a stroke? | Increases chance of blood clot forming (makes platelets more sticky). |
| How does carbon monoxide increase the risk from a stroke? | Reduces the amount of oxygen available from the blood. |
| How does smoking increase the chance of developing lung cancer? | Cigarette smoke contains many carcinogens, which may cause mutations in DNA of lung cells, causing uncontrolled cell growth and the formation of a malignant tumour. |
| What happens in lung cancer? | Malignant tumours grow uncontrollably, blocking air flow to areas of the lung, decreasing gas exchange and leading to shortness of breath. The tumour also uses lots of nutrients and energy to grow, causing weight loss. |
| What is chronic bronchitis? | Inflammation of the lungs. |
| What happens in chronic bronchitis? | Smoke damages the cilia in the lungs and causes the goblet cells to produce more mucus, which accumulates in the lungs. Increased coughing to try and remove the mucus. |
| Effects of chronic bronchitis? | Microorganisms multiply in mucus and cause lung infections that lead to inflammation, which decreases gas exchange. |
| What are chronic bronchitis and emphysema a type of? | Chronic obstructive pulmonary disease – a group of diseases that involve permanent airflow reduction. |
| What is emphysema? | A lung disease caused by smoking or long term exposure to air pollution – foreign particles in smoke or air become trapped in the alveoli. |
| What happens in emphysema? | Trapped foreign particles cause inflammation of emphysema, phagocytes come to area, and produce an enzyme that breaks down elastin in alveolar walls. Alveolar walls destroyed and elasticity lost. |
| What are the effects of emphysema? | Reduced surface area of alveoli decreases rate of gaseous exchange, causing shortness of breath and wheezing. |
Created by:
emm142
Popular Biology sets