click below
click below
Normal Size Small Size show me how
Biology 2.2.2
AS OCR biology - health and disease
| Question | Answer |
|---|---|
| What is health? | A state of physical, social and mental wellbeing, not just the absence of disease |
| What is disease? | A departure from good health, caused by malfunction of body or mind, causes physical and mental symptoms |
| What is a parasite? | An organism that lives on a host internally (tapeworm) or externally (head louse). Parasite gains nutrition from hsot, host is harmed and is vulnerable to invasion by other microorgansisms causing secondary infections |
| What is a pathogen + examples + characteristics? | An organism that causes disease. Bacteria- prokaryotae kingdom, divide by binary fission, release toxic waste products and damage cells e.g. cholera, TB. Viruses- invade cells by binding to protein receptors on surface, use genetic machinery to replicate |
| Continued | e.g HIV/AIDS. Fungi live in skin send out reproductive hyphae that release spores from skin surface e.g. athlete's foot, ringworm. Protists - invade cells and feed on contents as they grow e.g. malaria |
| What do the terms prevalence, morbidity, incidence and mortality mean? | Prevalence - the number of people with a disease at one point in time. Morbidity - number of people with disease as a proportion of the population. Incidence - number of new cases of a disease in a year. Mortality -number of deaths from a disease per year |
| What do the terms pandemic, epidemic, endemic and transmission mean? | Pandemic - worldwide epidemic. Epidemic - disease spreading rapidly over large area. Endemic - disease always present in a population. Transmission - the way that a pathogen travels from one host to the next |
| What is malaria caused by? | Eukaryotic protist from genus Plasmodium, e.g. P.Vivax, P. falciparum, P.ovale, P.malariae |
| How is malaria transmitted? | Anopheles mosquito (vector) feeds on haemoglobin and transmits Plasmodium from an infected individual to another person. Unscreened blood transfusions, unsterilised needles, across the placenta |
| What is the lifecycle/transmission pattern with the anopheles mosquito? | If host has malaria, mosquito sucks gametes into stomach fuse to form gametes. Sporozoites in salivary glands. New host: injects saliva as anticoagulant. Sprozoites multiply in liver then enter red blood cells and release gametes |
| What is the global impact of malaria? | 300 million people infected, 90% in sub-Saharan Africa, 3 million deaths per year, limited to tropical regions where anopheles mosquito can survive, endemic, global warming is allowed mosquito to survive further north |
| What is HIV/AIDS caused by/ how does it affect the body? | HIV virus binds to complementary receptors on Th cells, uses cell's genetic machinery to replicate, cell bursts, releasing viruses, when number of Th cells < threshold level =AIDS. HIV/AIDS weakens immune system-> opportunist infections e.g. pneumonia |
| How is HIV/AIDS transmitted? | Exchange of body fluids. Blood-to-blood contact: sharing hypodermic needles, needle-stick, unscreened blood transfusions. Unprotected sex. Mother to baby, across placenta, childbirth and breast milk. Unsterilized medical equipment |
| What is the global impact of HIV/AIDS | Pandemic, prevalence 30 million, 70% in sub-Saharan Africa |
| What is TB caused by? | 2 bacteria strains: Mycobacterium tuberculosis, Mycobacterium bovis. affects the lungs |
| How is TB transmitted? | Droplets released when an infected person talks, laughs, coughs or sneezes. Can be contracted from the milk and meat of cattle. Factors encouraging spread: homelessness, poor ventilation, poor health, poor diet, overcrowding |
| What is the global impact of TB? | Pandemic, 30% of global population currently infected, 1% newly infected per year, common in South-east asia and sub-saharan africa, some strains are becoming resistant to drugs |
| What are leucocytes, types and properties? | White blood cells made in bone marrow.1)phagocytes-engulf+ingest pathogens- 2 types: neutrophils (60%, die after engulfing, lysosomes+lobed nucleus), macrophages (larger, lysosomes, survive after engulfing p). 2)lymphocytes - B(bone marrow), T(thymus g) |
| What are the features of the non-specific immune response? |