CB5 Health And Disease

• communicable disease = Caused by PATHOGENS

  Can be spread from one infected person to another
• non-communicable disease = Caused by a problem in the body such as genes or lifestyle.

  Cannot be spread from one infected person to another
• Pathogen – an organism that causes a disease
• Sometimes having one disease can mean that you are more likely to have another. Due to a disease might damage:

  1. the immune system so other pathogens can cause disease 
  2. our barriers
  3. an organ working effectively so other disease can occur.
• Cirrhosis (NC) - from alcohol
• Malnutrition (NC) - unbalanced diet
• cardiovascular (NC) - unbalanced, smoking, lack of excercise
• lung disease (NC) - smoking
• obesity (NC) - unbalanced diet high in sugar and fat
• lung cancer (NC) - smoking
• Obesity can lead to too much fat around organs which can cause cardiovascular disease and heart attack.
•  BMI is used to predict the amount of fat in our body
• Measurement of waist-to-hip ratio by dividing waist measurement by hip measurement can also be used. 
• A gastric band helps people lose weight.

  This is because it reduces the volume of the stomach:

  • So it reduces food intake
  • So stored fat is used up 
• Exercising can help people lose weight because:

  • Exercise uses energy
  • Obtained from fat in the body
• The liver has to break down alcohol and a large amount can lead to CIRRHOSIS.

  A cirrhotic liver can lead to death.
• Harmful chemicals in tobacco smoke can :

  1. Damage blood vessels
  2. Increase blood pressure
  3. Make blood vessels narrower and so increase the risk of blood clots

  All these can lead to cardiovascular disease which can then lead to heart attacks or strokes.
• Surgical procedures for cardiovascular disease

  1. A narrowed blood vessel can be widened by inserting a small mesh tube called a STENT. They allow greater blood flow and more oxygen delivered to the organ.
  2. Blocked arteries in the heart can be by-passed by inserting other blood vessels so that blood can flow again to the heart tissue.
  3. Weight loss surgical procedures e.g. gastric band.
• Life-long medication for cardiovascular disease

  These may be given to reduce blood pressure.
• Lifestyle changes for cardiovascular disease

  Doctor advises to exercise more and give up smoking.
• communicable diseases (need pathogen)

  
• Infection with HIV can lead to AIDS – HIV destroys white blood cells, therefore a person is more susceptible to other communicable disease
• physical barriers =

  • Skin
  • Hairs in nose
  • Cilia and mucus in airways. Mucus is a sticky substance that traps bacteria and cilia waft it away.
• chemical barriers =

  • Acid in stomach – kills bacteria
  • Lysozyme in tears – kills bacteria
• Immune response


  1. Pathogen gets past the physical and chemical defences and enters the body

  2. Antigens on the surface of the pathogen trigger an immune response

  3. Antibodies on the surface of lymphocytes fit into the antigens and stop the pathogen working

  4. White blood cells called phagocytes engulf pathogens and release chemicals to destroy them

  5. Pathogen’s antigens trigger production of memory lymphocytes

  6. Memory lymphocytes trigger a rapid release of the specific antibodies of a secondary response to stop the pathogen

  7. Now immune to the pathogen
• If you have a bacterial infection, the number of white blood cells will increase. This is because the white blood cells kill pathogens like bacteria.
• Safety Precautions when handling blood samples =

  • Wear gloves/ goggles/cover wounds
  • Clean up spills/ use tongs to handle samples
  • Store samples in sealed containers
  • Dispose of samples safely
• Immunity to a pathogen is called IMMUNISATION.

  It can happen naturally or by using a VACCINE.
• A vaccine contains an inactive weaker version or only parts of a pathogen that include the antigens.

  Once given, your body produces memory lymphocytes to make you immune.
• Vaccines can be given as an injection or in the mouth
• Antibiotics are substances that either kill bacteria or inhibit  their cell processes.

  They do NOT have this effect human cells.

  They do NOT affect viruses.
• Stages in the production of a new antibiotic:

  1. Pre-clinical stage: new antibiotic is tested on cells. 
  2. Antibiotic then tested on animals.
  3. Clinical trial: antibiotic tested on a small number of humans to check that any side effects are small.
  4. Larger clinical trail: many people tested to try to find the correct dose.