Health & disease - Spec

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  • Created by: rachel
  • Created on: 21-03-13 15:18
What is meant by the term health?
A state of mental, physical & social wellbeing, not just the absence of disease.
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What is meant by the term disease?
A departure from good health caused by a malfunction of the mind or body.
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Define & Discuss the meaning of the term parasite.
An organisms that lives on/in another living thing causing harm to its host. It feeds on the host receives warmth & protection & the host allows for the transmission of the parasite to a new host.
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Define & Discuss the meaning of the term pathogen.
An organism that causes disease.
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Describe the first step in the causes & means of transmission of malaria.
1. Infective agent is Plasmodium falciparum carried by female Anopheles (vector). Parasite lives in mosquito & another animal during life cycle.
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Describe the second & third step in the causes & means of transmission of malaria.
2. If human already has malaria, female Anopheles mosquito will take the parasite gametes into its own stomach when it sucks/bites. 3. gametes fuse & zygotes develop in mosquito stomach.
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Describe the fourth & fifth step in the causes & means of transmission of malaria.
4. Infective stages are formed and these move to the mosquitos salivary glands. 5. When the mosquito bites another person, it injects a little saliva as an anticoagulant. The saliva contains the infective stages of the parasite.
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Describe the sixth & seventh step in the causes & means of transmission of malaria.
6. In the human host, the infective stages enter the liver where they reproduce before passing into the blood again. 7. In the blood they enter the red blood cells, where the gametes are produced.
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Describe the first & second steps in the causes & means of transmission of HIV/AIDS.
1. Infective agent is human immunodeficiency virus & it can enter body a number of ways (e.g. exchange of bodily fluids). 2. HIV (retrovirus) inserts its RNA into a T lymphocyte.
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Describe the third & fourth step in the causes & means of transmission of HIV/AIDS.
3. The enzyme reverse transcripts produces a DNA copy of the viral RNA 4. The DNA is inserted into the chromosome of the T lymphocyte.
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Describe the fifth & sixth steps in the causes & means of transmission of HIV/AIDS.
5. Viral mRNA is produced & makes viral proteins which then form many copies of the virus which are released from the T lymphocyte.
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Describe the sixth step in the causes & means of transmission of HIV/AIDS.
6. Once the virus becomes active in the body, it destroys T helper cells, effectively rendering the immune system useless.
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List some of the ways that the HIV virus can enter the body.
Exchange of bodily fluids, unprotected sex, unscreened blood transfusions, unsterilised surgical equipment, sharing hypodermic needles. 'needle-stick' accidents. Across placenta. During child birth. Breast feeding.
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Describe the first step in the causes & means of transmission of Tuberculosis.
1. Infective agent is Mycobacterium & the bacteria are contained in the tiny droplets of liquids which are released when a person coughs, sneezes or talks.
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Describe the second & third step in the causes & means of transmission of Tuberculosis.
2. In close contact with infected person for a long period of time, the disease will be transmitted.
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List the conditions that make the contraction & spread of TB more likely.
Overcrowding, poor health, poor diet, homelessness, living/working with migrants from areas where TB is more common. TB can also be contracted from the milk/meat from cattle.
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Discuss the global impact of Malaria.
Kills about 3 million people annually. Affects about 300 million people. Limited to areas where Anopheles mosquito can survive (tropic regions). Due to global warming, Anopheles mosquito may be able to survive further north, (Europe).
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Discuss the global impact of HIV/AIDS.
Spreading into pandemic proportions all over the world. 45 million people living with it at end of 2005 (more than half of these in sub-Saharan Africa). 5 million people infected each year. By end of 2005, 30 million deaths from disease.
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Discuss the global impact of Tuberculosis.
Aprox 1% of population is infected every year, and 10-15% of those will go on to develop disease. in 2005 there was 8.8 million new cases of TB & 1.6 million people died. Up to 30% of the worlds population may be infected with TB.
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Define the term immune response.
The specific response to a pathogen, which involves the action of lymphocytes & the production of antibodies.
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Define the term antigen.
Molecules that stimulate an immune response.
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Define the term antibody.
Protein molecules that can identify & neutralise antigens.
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Describe the primary defences against pathogens & parasites & their importance.
Skin-physical barrier. Mucus membranes-goblet cells. Ciliated epithelia-remove mucus full of pathogens. Blood clotting-prevents pathogens entering blood stream. Ear wax & nasal hairs-trap pathogens. Lysosome in tears & saliva-kills bacteria. Stomacha
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Describe the structure & mode of action of phagocytes.
Phagocyte receptor recognises antigen on plasma memb of bacterium. Phagocyte binds to bacterium. Pathogen engulfed by infolding of pahgo. membrane -> phagosome (P). Lysosome fuses with P -> Lysins. Bacterium digested. Goes in cytoplasm by diffusion.
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During the action of phagocytes, when the Bacterium are digested, what are they digested into?
Amino acids, sugars, glucose, fatty acids & glycerol.
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Describe the structure of antibodies.
Y shaped.4 polypep chains (2 light 2 heavy, joined by disulphide bonds) Constant region = marker allowing binding of phagocytes. Variable region(s)-agglutination & more pathogen attachments. Hinge-flexability. 4 polypep chains held by disulphide bird
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When does the hinge region of an antibody allow flexibility?
When more than one pathogen is attached.
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Outline the mode of action of antibodies, with reference to the neutralisation & agglutination of pathogens.
Attach to specific antigens. P use antigens as binding site. Antibody blocks binding site -> pathogen can't bind to host cells - this is neutralisation. Some A attach to more than 1 pathogen at time causing agglutinin- P easy to engulf & cant infect.
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why do we need cell signalling in terms of the structure & mode of action of T & B lymphocytes.
Immune response involves coordinated response between wide range of cells & to work efficiently, cells need to communicate.
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Describe the cell mediated response (T cells).
Multiplication of correct T killer cells (clonal expansion). T killer cells search for infected cells & attach to them. T killer cells secrete toxic substances (hydrogen peroxide) into infected cells to kill the cell & the pathogen it contains.
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Briefly describe the Humoral response (B cells)
Clonal selection. Clonal expansion.
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Explain how clonal expansion is activated.
T helper cells release a cytokine called interleukin which binds to a receptor on cell surface membrane of a B lymphocyte as they have complementary shapes. This activates clonal expansion.
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What is clonal selection?
When a B cell has an antigen receptor on its surface which is specific to only one antigen. T cells select the relevant specific B cell, this is clonal selection.
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What is clonal expansion?
Where the selected B cell divides by mitosis to produce clones. These clones differentiate to form plasma cells which produce antibodies. The antibodies are complementary to the antigen.
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Describe what memory cells do & what produces them.
Produced by T helper & B cells. Recognise virus & produce clone -> plasma cell to make antibodies. Responsible for secondary response which destroys virus etc before symptoms come. Circulate body for years -> faster 2 response to same infection
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Describe the primary immune response.
When the infecting agent is first detected, immune system starts to produce antibodies, but it takes a few days before the number of antibodies in the blood rises to a level that can fight infection.
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Describe the secondary immune response.
The immune system recognises the pathogen if the body is infected again, so the immune system can swing into action more quickly. The production of antibodies had a shorted delay, is more rapid & produces more antibodies.
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What is Natural passive immunity?
Antibodies are provided via the placenta or breast milk. This makes baby immune to diseases that mother is immune to. Very useful in 1st year of baby's life, when immune system is developing.
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What is Natural active immunity?
Immunity provided by antibodies made as a result of infection. A person suffers from disease once & is then immune.
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What is artificial passive immunity?
Immunity provided by injection of antibodies made by another individual. (e.g. tetanus)
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What is artificial active immunity?
Immunity provided by antibodies made in immune system as result of vaccination. Person is injected with weakened, dead or similar pathogen or with antigens & this activates immune system.
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Explain how vaccination can control disease?
Vaccination -> immunity. Vaccinated person has artificial immunity created by deliberate exposure to harmless antigenic material. Immune system treats antigenic material as if its real disease. So IS makes antibodies & M cells. M cells provide LT imm
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Discuss the responses of governments & other organisations to the threat of new strains of influenza.
Different strains of the virus as it mutates each year. New strains have different antigens. Antibody produced by vaccine needs to match new antigen. In UK theres immunisation program to vaccinate all in 'risk' groups.
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Who are the people in 'risk' groups, that would be offered vaccines?
Elderly, pregnant women, people with compromised immune system, those with chronic diseases, health workers, poultry workers & 'at risk' children.
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Outline possible new sources of medicines, with reference to microorganisms & plants & the need to maintain biodiversity.
Because there's lots of species of drugs in tropical rainforest that haven't been discovered, its hoped that theres lots of medicines to still discover. But biodiversity needs to be maintained - plants with medicinal properties need to be farmed sust
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Fill in the blanks: Research has been undertaken into way that microorganisms cause disease. Many use _____ on their _____ ______. The receptor sites can be _____ by a drug, & then the disease-causing pathogen cannot gain access to cell.
Receptors. plasma, membranes. blocked.
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Describe a short term effect of smoking on the mammalian gas exchange system.
Tar paralyses/destroys cilia on surface of airway -> unable to move the layer of mucus away & up to throat. Tar stimulates the goblet cells & mucus secreting glands to enlarge & release more mucus. Mucus collets in airway & trapped bacteria multiply
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Describe a long term effect of smoking on the mammalian gas exchange system.
Mucus & bacteria irritates airways, and they need to be cleared to get O2 into alveoli. Leads to smokers cough to try shift bacteria-laden mucus.
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What is chronic Bronchitis?
Inflammation if the lining of the airways, damage to the cilia & overproduction of mucus.
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What are the symptoms of chronic Bronchitis?
Irritation of lungs, continual coughing, coughing up mucus that's often filled with bacteria & white blood cells.
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What does 'chronic' mean?
Long term, takes time for symptoms to show & degenerative (gets progressively worse).
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What is Emphysema?
The loss of elasticity in the alveoli which causes them to burst.
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What are the symptoms of emphysema?
Shortness of breath, harder to exhale, fatigue occurs (blood is less well oxygenated), barrel chest, high BP to lungs, enlargement of right side of heart, heart failure.
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How is lung cancer caused?
Tar contains carcinogens & enters epithelial cells. Tar destroys cilia -> prevents removal of tar which has greater contact time with epithelial cells. Carcinogens enter nucleus & cause mutation. Causes uncontrolled cell division & tumour forms.
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What carcinogens are in Tar?
benzopyrene & formaldehyde
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What are the symptoms of lung cancer?
Continuous cough, shortness of breath, pain in chest, blood coughed up in sputum.
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Describe the effects of Nicotine in tobacco smoke on the cardiovascular system with reference to the course of events that lead to arteriosclerosis, CHD & stroke.
Causes addiction. Mimics effects of transmitter substances at synapses (makes smoker more alert due to over-sensitve nervous system). Releases adrenaline, makes platelets sticky (> risk of blot clotting/thrombosis) Constricts arterioles to extremity
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Describe the effects of Carbon Monoxide in tobacco smoke on the cardiovascular system with reference to the course of events that lead to arteriosclerosis, CHD & stroke.
Hb has higher affinity for CO than O2. CO + Hb -> carboxyhaemoglobin (very stable). This reduces O2 carrying capability of blood. Body will detect lower levels of O2 & heart rate will rise damaging endothelium of arteries.
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Describe the effects of Atherosclerosis in tobacco smoke on the cardiovascular system with reference to the course of events that lead to arteriosclerosis, CHD & stroke.
CO damages endothelium of arteries. Phagocytes repair damage. Encourages growth of smooth muscle & deposition of fatty subst under endothelium. Artheroma forms plaque - sticks into lumen or artery. Leaves artery less flexible & rougher reducing BF
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What might the deposits in the endothelium of arteries in Atherosclerosis include?
Deposits may include fibres, dead blood cells & platelets. & The deposits include cholesterol & LDLs
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Describe the effects of CHD in tobacco smoke on the cardiovascular system with reference to the course of events that lead to arteriosclerosis, CHD & stroke.
Coronary arteries carry blood at high pressure which makes them prone to damage & atherosclerosis. When lumen of CA is narrowed by plaques, less blood flow to heart so receives less O2 for aerobic respiration & blood carries away less CO2.
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What are the signs of Angina?
Type of CHD. Severe pain in chest which may extend down left arm or up the neck
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What is a heart attack?
Type of CHD. The death of a part of the heart muscle, usually caused by a clot in coronary artery blocking flow of blood to heart muscle.
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When does heart failure occur?
(Type of CHD) When the heart cannot sustain its pumping action; this can be due to the blockage of a major coronary artery.
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What is a stroke?
The death of part of the blood tissue due to the loss of blood flow to that part of the brain. This can also occur when an artery leading to the brain bursts.
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What is meant by the term disease?

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A departure from good health caused by a malfunction of the mind or body.

Card 3

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Define & Discuss the meaning of the term parasite.

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Preview of the front of card 3

Card 4

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Define & Discuss the meaning of the term pathogen.

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Card 5

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Describe the first step in the causes & means of transmission of malaria.

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Swallowtail

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A good collection of over 60 revision cards which will give you the information you need to revise thoroughly the unit on health and disease found in the OCR specification. As well as testing key biological terms used in immunology they contain useful information on the transmission of diseases such as HIV/AIDS,tuberculosis and malaria.

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