communicable diseases

• communicable diseases are diseases that can be spread either directly or indirectly via another species, such as measles and chicken pox
• non-communicable diseases cannot be spread, such as cancer, diabetes and heart disease
• a pathogen is a microorganism that causes disease
• the 4 types of pathogens are:

  • protista
  • fungi
  • bacteria
  • virus
• bacteria can reproduce rapidly inside the body and produce toxins that damage tissues and make us feel ill
• viruses can live and reproduce inside cells causing cell damage
• • influenza is transferred by airbone droplet infection
  • hiv is transferred by direct contact
  • cholera is transferred via water
• primary defences are the bodys initial barriers such as skin, mucus and stomach acid
• the two types of white blood cells are phagocytes and lymphocytes
• an antigen is a substance on pathogens that stimulates the production of antibodies
• an antibody is a y shaped protein produced by b lymphocytes that binds to antigens
• phagocytosis is the process where a type of white blood cell called a macrophage ingests and destroys a pathogen
• b lymphocyte is a white blood cell that produced antibodies
• an antitoxin neutralises the toxins released by pathogens
• immune response is the bodys defence against foreign material such as pathogens
• t lymphocyte is a type of white blood cell that recognises and destroys pathogens and coordinates the immune response
• antibiotics are chemicals produced by microorganisms like fungi and kill bacteria
• digitoxin

  • from foxglove
  • strengthens heartbeat for heart patients
  • large amounts can be toxic
• aspirin

  • from bark of willow trees
  • anti inflammatory and pain reliever
• penicillin was discovered by fleming when doing research on the growth of a bacteria
• what makes a good drug:

  • efficacy
  • dosage
  • toxicity
  • efficient
• stage 1 - drug is tested using computer models and human cells

  stage 2 - drug is tested on animals

  stage 3 - drug is tested on healthy volunteers

  stage 4 - drug is tested on volunteers with the illness

  stage 5 - drug istested on a large population

  stage 6 - drug is licenced to a company
• cancer is a large group of diseases characterised by uncontrolled growth and spread of abnormal cells
• a benign tumour is the growth of abnormal cells in one place within a membrane. it doesnt spread but grows quickly
• a malignant tumour spreads around the body invading healthy tissues
• radiotherapy uses radiation to destroy cancer cells by stopping mitosis but it can damage healthy cells
• chemotherapy uses chemicals to stop mitosis in cancer cells or make them self destruct