immune system

• Mechanisms for bodies first line of defence is

  • skin physical barrier
  • mucus membranes and hairs
  • chemical methods in sweat, saliva and tears
  • harmless bacteria on skin surface
• Chemical defences

  • HCL stomach acid
  • lysozymes in tears
  • saliva
• white blood cells produced in bone marrow are phagocytes and lymphocytes
• Puss is made from dead phagocytes, destroyed bacteria and other cell debris
• An antigen is any substance that triggers an immune response. Usually a protein, carbohydrate or toxin
• A toxin is a chemical released by certain invaders
• Bacterium called tenataus bacterium release toxins
• A toxoid is a modified toxin to be used safely in vaccinations
• cytotoxic T cells kill infected cells by punching holes into them with a protein called perofin
• Non specific defences the response is immediate and the same for all pathogens. Examples are skin or phagocytosis
• Specific defences is a slower response and specific to each pathogen. Examples are T lymphoctyes and B lymphocytes
• Self antigens are receptors on the cell surface membrane that identifies the bodies own cells
• foreign antigens are on the surface membrane of pathogens invading the bodies immune system
• An antigen is any part of an organism or substance that is recognised as foreign by the immune system and stimulates an immune response. They are usually large complex proteins
• Cell mediated response involves T lymphocytes/ T cells
• Cell mediated respond by making clones not antibodies
• Types of T cells

  • memory T cells
  • cytotoxic killer T cells
  • Helper T cells
• T cells are produced in the bone marrow and matured in the thymus
• humeral response involves B lymphocyte/ B cells
• B cells are produced and mature in bone marrow
• APC is a antigen presenting cell
• Lysozymes work in a phagocytic vesicle and not free in the cytoplasm because if they were free they would hydrolyse the cells organelles. Being in the vesicles makes the lysozymes target the pathogen
• Molecules that acts as antigens

  • pathogens
  • foreign antigen
  • cancerous antigen
  • toxins
• An antibody is a protein produced by the immune system (B cells) in response to the presence of an appropriate antigen
• Primary response is slow and produces a small concentration of antibodies
• Secondary response is quicker and produces a higher concentration of antibodies
• Antigenic variability is pathogens that can change the antigen on their cell surface membrane
• Active immunity results from your immune system producing memory cells following exposure to antigen
• Passive immunity results from being given antibodies from a different organism

  mother to baby through placenta/ blood injection for tetanus
• agglutination is the process of antibodies clumping together pathogens to create a large clump to be destroyed by phagocytes
• Active artificial immunity is when an antigen is injected and the body produces its own antibodies specific to that antigen
• Passive artificial immunity is gained by being injected with antibodies to a specific pathogen from another person. This does not create memory cells and only fights an infection that is already present in the body
• A vaccine is a preparation of an antigen from a pathogen injected to trigger an immune response to increase immunity to that specific pathogen
• A monoclonal antibodies is a type of antibody that has been isolated and cloned
• Direct monoclonal antibody uses

  • detecting and marking cancerous cells
  • triggering the body to destroy cancerous cells
• Indirect monoclonal antibody uses

  • deliver cancer drugs to cancer cells
• Immunoassay is a biochemical test that measures the presence or concentration of a macromolecule in a solution brought the use of an antibody or immunoglobulin
• The ELISA test enables you to see if a patient has a particular antibody to a certain antigen and so diagnose the presence of a disease
• How HIV causes the symptoms of AIDS

  HiV kills/ interfere with helper T cells which reduces the bodies immune response meaning it is more susceptible to infections and cancer
• neutrophils engulf and surround pathogens to destroy them with lysozymes to produce phagocytic vesicle.