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2011-05-26 06:47:08
Biology Food Health

Food and Health
Show Answers:

  1. What causes malaria?
  2. What vector spreads malaria?
    Female Anopheles mosquito
  3. What cells do malarial parasites live in?
    • Red blood cells
    • Liver
  4. What causes AIDS?
  5. What causes TB?
    Mycobacterium tuberculosis
  6. Global impacts of malaria
    • Kills 3 million per year
    • Affects 300 million
    • In tropical regions
  7. Global impact of AIDS
    • Speading in pandemic proportions
    • 45 million living with it
  8. Global impacts of TB
    • 1.6 million killed
    • 30% of worlds population
  9. Primary defences
    • Skin
    • Mucus
    • Tear fluid
    • Ear wax
    • Stomach acid
  10. Secondary defences
    • Phagocytes:
    • Neutrophils- manufactured in bone marrow, released in large numbers
    • Macrophages- larger cells, initiate immune response
    • engulf and destroy pathogens
  11. Phagocytosis
    • Pathogen attached to phagocyte by antibody and surface receptors
    • Pathogen engulfed by infolding of phagocyte membrane
    • Lysosomes release lysins into phagosome
    • Harmless end products of digestion are absorbed
  12. Antibodies
    • Produced by lymphocytes
    • protein molecules that can identify and neutralise antigens
  13. Balanced diet
    • a diet that contains all the nutrients required for health in appropriate proportions
    • contains: carbohydrates, proteins, fats, vitamins, minerals, water, fibre
  14. Unbalanced diet
    • malnutrition
    • deficiency
    • obesity: consuming too much energy, causes cancer, type 2 diabetes, cardiovascular disease, gallstones and osteoarthritis
  15. High blood cholesterol
    • high-density lipoproteins (HDL): produced by unsaturated fats, cholesterol and protein, carry cholesterol from body tissues to liver, reducing blood cholesterol levels, reduce deposition in the arteries
    • low-density lipoproteins (LDL): produced by saturated fats, carry from liver to tissues, causes depostion in arteries
  16. Coronary heart disease
    • caused by the deposition of fatty substances in the walls of the coronary arteries (atherosclerosis)
    • diet: salt (decrease water potential of blood), fats, cholesterol
  17. Preventing food spoilage
    • cooking: denatues enzymes
    • salting: dehydrate microorganisms
    • smoking: antibacterial chemicals
    • pickling: acid pH denatures enzymes
    • irradiation: disrupt DNA structure, kills
    • freezing: retard enzyme activity
  18. Microorganisms to make food
    • e.g. Quorn
    • Advantages: production faster,no animal welfare issues, good source of protein for vegetarians, no animal fat
    • Disadvantages: isolation of protein, protein has to be purified, infection, palatability
  19. What is health?
    a state of mental, physical and social wellbeing, not just the absence of disease
  20. What is disease?
    a departure from good health caused by a malfunction of the mind or body
  21. What is a parasite?
    an organism that lives in or on another living thing, causing harm to its host
  22. What is a pathogen?
    an organism that causes disease
  23. What is immune response?
    • the specific response to a pathogen, which involves the action of lymphocytes and the production of antibodies
    • primary: combating first infection
    • secondary: responding to a second infection quicker
  24. How do antibodies work?
    • attaching to antigens
    • neutralisation: antibodies covering the pathogen binding sites prevent the pathogen from binding to a host cell and entering the cell
    • agglutination: binding many pathogens together, the group of pathogens is too large to enter a host cell
  25. What is an antigen?
    molecules that stimulate an immune response
  26. T lymphocytes
    • have different receptor molecules on their surface
    • If an antigen is presented to a T cell with a complementary shaped receptor, the T cell is stimulated, increases in size and starts to divide.
    • A clone of identical T cells is formed, all with the correct shaped receptor. These T cells then differentiate to form 4 groups of specialised T cells. These are:

    • Killer T cells
    • Helper T cells
    • Suppressor T cells
    • Memory cells

    kill infected cells
  27. B lymphocytes
    form a clone if it comes into contact with a complementary shaped antigen. The clone contains mostly plasma cells for immediate use and some memory cells for use in the future

    manufacture antibodies
  28. Vaccination
    deliberate exposure to antigenic material which activates the immune systemto make an immune response and provide immunity
  29. Immunity
    • Active: immunity achieved by activation of the immune system, last for many years
    • Passive: provided by antibodies that have not been manufactured by stimulating the recipient's immune system
    • Natural: gained by living processes
    • Artificial: gained by deliberate exposure to antibodies or antigens
  30. New sources of medicines
    • microorganisms
    • plants
  31. Smoking: chronic bronchitis
    • inflammation of the lining of the airways
    • damage to cilia
    • overproduction of mucus
    • symptoms: irritation in the lungs, coughing, coughing up mucus, lung infection
  32. Smoking: emphysema
    • loss of elasticity in the alveoli- alveoli bursts, harder to exhale
    • symptoms: short of breath
    • chronic obstructive pulmonary disease
  33. Smoking: lung cancer
    symptoms: coughing, short of breath, pain in chest, blood coughed up
  34. Smoking: short term effects
    • lumen of airway gets smaller
    • destroyed cilia
    • mucus and bacteria block airway
    • lungs more susceptible to infections- influenza or pneumonia
  35. Smoking: long term effects
    • airways and alveoli become damaged- replaced with scar tissue
    • frequent infections
  36. Smoking: nicotine
    • causes addiction
    • mimics the action of transmitter substances
    • causes release of adrenaline
    • causes constriction of the arterioles
    • makes platelets sticky
  37. Smoking: carbon monoxide
    • combines with haemoglobin
    • damage lining of the arteries
  38. Smoking: atherosclerosis
    • CO damages endothelium of the arteries
    • damage repaired by white blood cells
    • growth of smooth muscle and deposition of fatty substances
    • deposition known as atherosclerosis- occurs under the endothelium
  39. Smoking: coronary heart disease
    • narrowing of lumen by plaques
    • angina: severe pain in chest
    • heart attack: death of part of the heart muscle
    • heart failure: heart cannot sustain its pumping action
  40. Smoking: stroke
    • death of part of the brain tissue
    • causes: blood clot and artery leading to the brain bursting (haemorrhage)
  41. Coronary heart disease- factors
    • age
    • gender
    • smoking
    • obesity
    • high blood pressure
    • high blood cholesterol levels
    • physical activity
    • diet
    • high salt intake
    • genetic factors
    • diabetes
    • stress
  42. Epidemiology
    the study of the distribution of a disease in populations and factors that influence its spread