Disease and Immunity

Disease
1. Causes
  1. Infections caused by pathogens e.g bacteria and viruses. For example common cold, food poisoning and chest infections
  2. Non infectious disease- caused by malfunctioning of the body e.g cancer
2. Lifestyle
  1. Coronary Heart Disease (CHD): -Poor diet (high in saturated fat or salt) -Smoking -lack of exercise
    1. All lead to high BP, which can damage the heart and blood vessels, increasing risk of CHD
  2. Cancer, result of uncontrolled cell division: -Smoking (mouth, throat and lung cancer) -Excessive exposure to sunlight; skin cancer -Excessive alcohol intake; liver cancer
3. Risk Factor= anything that increases the chance of getting a disease
Pathogens
1. Organism that can cause disease
2. Types of Pathogen
  1. Viruses
    1. HIV-Aids + Influenza
  2. Bacteria
    1. Myobacterium Tuberculosis
  3. Entry into the body
    1. Gas Exchange System
      1. Mucus trap pathogens, cilia beat and move mucus up trachea and out of the mouth
    2. The Skin
      1. Blood clots and dries to form a scab
    3. Digestive System
      1. Most pathogens killed by acidic conditions of the stomach
3. How they cause disease
  1. 1. Production of Toxins
  2. 2. Cell Damage- kill host cells
    1. i). rupture host cell to release nutrients
      1. ii) Break down nutrients for own use, this starves the cell
        iii) cell dies, pathogens replicate inside cells and eventually they burst
The Immune Response
1. 1. Phagocytosis
  1. 1. Phagocyte recognises antigens on surface
  2. 2. Cytoplasm of phagocyte moves around the pathogen, engulfing it
  3. 3. The pathogen is now in a phagocytic vacuole
  4. 4. A lysosome fuses with the phagocytic vacuole, the lysosomal enzymes break down the pathogen
  5. 5. Phagocyte then presents the pathogens antigens on its own surface in order to activate other immune system cells
2. 2. T-Cell Activation (Cellular Response)
  1. Type of white blood cell, has proteins on its surface that bind to antigens on phagocytes
    1. Some T-cells release substances to activate B cells. Others attach to antigens on the pathogen and kill the cell.
3. 3. B-Cell Activation& Plasma cell production (Humoral Response)
  1. B Cells= Type of white blood cell
    1. Covered with antibodies (proteins that bind antigens to form an antigen-antibody complex)
    2. Each B cell has a diff shaped antibody on its membrane
      1. Meets complimentary antigen+ binds. This, together with substances released from T-Cells activate the B-Cells and cause them to divide (Plasma cells)
4. 4. Antibody Production
  1. Plasma cells are identical to B cells (clones) so they secrete loads of antibodies specific to the antigen
    1. Antibody Functions:
      1. Coating pathogen so the phagocyte can easily engulf it
        Binding to and neutralising toxins produced by pathogen
5. Antibody Structure
  1. Proteins- made of chains of AA monomers, linked by peptide bonds
    1. Each antibody has a diff shaped variable region due to diff amino acid sequences
6. Primary Response
Vaccines
1. Helps avoid a disease
Antigenic Variation
Monoclonal Antibodies

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Disease and Immunity

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	Criado por haleema290 mais de 10 anos atrás