• non specific (innate) immunity

  • barriers

  • repressive actions

  • blood clotting and wound repair

  • fevers

  • phagocytosis

• neutrophils - lobed nucleus. Phagocytosis

• lymphocytes - formed in the bone marrow and stored in the lymph

• monocytes - macrophages - large kidney shaped nucleus. Phagocytosis

• eosinophils - allergic response

• basophils - mast cells - histamines

• why is fever a useful adaptation:

  • cause it stops the pathogens from replicating

  • increases the body temperature

  • normal core body temperature is 37 degrees

  • this is controlled by the hypothalamus in the brain

  • during infection the large presents of white blood cells causes the hypothalamus to reset,increasing temperature

  • this is because pathogens cannot reproduce as quickly at temperature above 37 degrees,and the specific immune system can work faster

• inflammatory response:

  • inflammation is swelling of skin immediately around the rupture

  • this is characterised by pain,heat and redness

  • mast cells are activated when skin is ruptured they release histamine and cytokines

  • histamine these make blood vessels dilate,causing localised heat and redness.high temperature prevent pathogen reproduction

  • histamines also increase the permeability of the cell wall,causing more tissue fluid to escape causing swelling and the pain

  • cytokines attract WBC to deal with any pathogens

specific immune response

• phagocytes and lysosomes are involved in destroying macrophages

  • phagocytes engulf pathogens/macrophages

  • enclosed in a vacuole

  • lysosomes have enzymes that digests molecules

• antibody actions

  • opsonisation

  • disable pathogen (antibody-antigen complex)

  • agglutination

  • deactivate antitoxins

• how antibodies work

  • antibody - antigen complex acts similar to the opsonin chemical,by stimulating the digested by phagocytosis

  • most pathogens cannot affect the bodies cells once they formed an antibody-antigen complex

  • agglutination - one antibody binds to two pathogens,causing them to clump together

  • this makes pathogens more easily engulfed by phagocytosis

  • neutralisation - antibodies can act as antitoxins binding with toxins produced by pathogens

  • this makes them harmless

• what are lymphocytes

  • lymphocytes are a type of WBC found in the blood and lymph nodes and a transition microscope should be used to see them

  • lymphocytes recognise antigen molecules on the surface of pathogens,and co-ordinate the immune response against that pathogen

  • collectively, lymphocytes can recognise millions

  • two main types of lymphocytes are B and T

  • b-lymphocytes mature in the bone marrow

  • t-lymphocytes mature in the thymus

  • t-helper cells - these cells produce interleukins, a type of cytokine.this stimulate B cell and antibody production,and attracts other t-cells and antibodies.

  • t-killer cells - these cells kill pathogens by producing a chemical called perforin, which makes holes in pathogens cell plasma membranes

  • t-memory cells - these act as the immunological memory,as they remain in the blood for long periods of time.when a second infection occurs,they divide rapidly to form many killer T cells.

  • t-regulator cells - these prevent an autoimmune response by repressing the immune system after the pathogens have been destroyed.

• b-lymphocytes

  • plasma cells - these produce specific antibodies to an invading antigen.these only live for a few days but produce up to 2000 antibodies per second when active

  • b-effector cells - these divide to form plasma cell clones

  • b-memory cells - these remain in the blood for long periods of time,providing immunological memory.if infection occurs these reproduce rapidly and produce the same specific antigen.