health and disease

• communicable disease


  can be passed from one organism (person) to another
• non-communicable disease


  a disease which is not passed from an organism (person) to another
• health

  being free from communicable and non-communicable diseases
• what effect has the presence of disease on society

  unhealthy people may not be able to work and require care.

  The NHS spends billions of pounds per year treating and looking after sick people.

  Most of the NHS budget is spent on medicine and the salaries of doctors and nurses.
• name 3 viral communicable diseases

  HIV (leading to aids)

  cold/flu

  human papilloma virus (HPV)
• how is HIV spread

  Exchange of body fluids during sex. Infected blood.
• what is the control/prevention/treatment of HIV

  Prevention: Using a condom. Drug addicts not sharing needles. Control: Drugs currently control the condition.
• how is cold/flu spread

  airborne
• how is cold/flu prevented

  flu vaccine
• how is HPV spread

  sexual contact
• how is HPV prevented

  HPV vaccination (offered to 12-13 years old girls and boys). Protects women and girls against cervical cancer.
• name 3 bacterial communicable diseases

  salmonella, tuberculosis, chlamydia
• how is salmonella spread

  contaminated food
• how is salmonella prevented/treated

  Prevention: Always cook food thoroughly. Do not mix cooked and uncooked foods. Treatment: Antibiotics.
• how is tuberculosis spread

  airborne
• how is tuberculosis treated

  anti-biotics
• how is chlamydia spread

  sexual contact
• how is chlamydia prevented/treated

  Prevention: Using a condom. Treatment : Antibiotics.
• name 2 fungal communicable diseases

  athletes foot, potato blight
• how is athletes foot spread

  direct contact
• how is athletes foot prevented/treated

  Prevention: Avoiding direct contact with spores (e.g. wear flip flops in changing rooms). Treatment Anti-fungal treatment.
• how is potato blight spread

  Spores are spread in the air from plant to plant (especially in humid, warm conditions).
• how is potato blight prevented/treated

  Prevention: Crop rotation. Treatment: Fungicide.
• how does bacteria cause disease

  damage cells or secrete toxins which damage cells
• how does fungi cause disease

  secrete enzymes onto cells, damaging them
• how do viruses cause disease

  infect living cells and use these cells to produce more viruses
• what are microorganisms which cause disease called

  pathogens
• Why are viruses not considered living?

  They cannot reproduce by themselves
• what do fungi feed on

  dead/living things - causing disease
• prevention of droplet infection

  wear masks, cover mouth/nose when sneezing or coughing
• prevention of water transmission

  treat water to kill microbes before drinking
• prevention of animal transmission

  killing/preventing insects from breeding (interrupt life cycle of the vector)
• prevention of transmission by contact

  wash hands regularly, clean/disinfect highly touched areas
• how do eyes defend against infection

  tears contain lysozyme which kills bacterial cells
• how do lungs defend against infection

  mucus membranes present in respiratory system which produce mucus which traps microbes. mucus expelled upwards away from lungs via ciliated epithelia lining trachea
• how do blood clotting defend against infection

  stops blood escaping and prevents entry of microorganisms where the skin has been damaged.

  Inflammation at sight of wound - local increase kills microbes
• how does the stomach defend against infection

  hydrochloric acid kills microbes entering via food
• how does the skin defend against infection

  acts as a physical barrier to entry of microorganisms and oily layer from sebaceous glands on skin surface has antimicrobial properties
• how do WBCs defend against disease

  1. Invading microorganisms have foreign antigens on their surface.

  2. When the body recognises a foreign antigen, lymphocytes (white blood cells) produce antibodies, which are complementary in shape to the antigen.

  3. An antibody will only work on one type of microorganism because of this complementary nature.

  4. Antibodies immobilise microorganisms by clumping them together.

  5. Immobilisation of the microorganism reduces symptoms and prevents the spread of infection.

  6. The clump of microorganisms is then destroyed by phagocytosis.

  7. Phagocytosis is when a phagocyte (white blood cell) engulfs and digests the microorganisms.

  8. Enzymes within the phagocyte digest the microorganism.
• primary response


  The infected individual will be sick while lymphocytes work to produce enough antibodies to provide immunity.