The document discusses the human immune system's defence mechanisms. It describes the primary and secondary immune responses. The primary response has a lag period where no antibodies are produced, while the secondary response is faster due to immunological memory from previous exposures. It also outlines the different types of white blood cells like B cells, T cells, and macrophages that work together to identify and eliminate pathogens. Key components of the immune system discussed include antibodies, cytokines, the major histocompatibility complex, and vaccination.

1. Describe: Defence Mechanisms - Humans b.stev

3. Gamma globulin proteins Basic structural unit-two heavy chains, two light chains 5 different antibody types each directing the reponse to encounter IMMUNOGLOBULINS (antibody) IN: blood and body fluids USED : identity to neutralise foreign bodies PRODUCED: B lymphocytes (B cells) CIRCULATES in the blood - binds to pathogen before entering the cell - stimulates it’s removal, coats the pathogen for identity by phagocyte: (a digester) - can stimulate direct response of complement pathway

4. IT IS THE , “ TIP ,” that differs to allow millions of varieties: - gives specific response to particular foreign body - attaches to commence immune response - TIP binds: identity of pathogen: called the “ EPITOPE ” ANTIBODY : produces attachment of a TAG to the pathogen: that shows expression for the next phase identity to it’s MATCH of the B cell & then T cell (Wikipedia, 2008)

5. ANTIBODY IgD IgE IgG binding site pathogen 5 DIFFERENT isotopes known as: IgA IgM

6. IgA: mucosal areas (saliva/ tears/ breast milk) urogenital/ gut/ respiratory IgD: less defined: use on unknown pathogens IgE: allergens – triggers histamine release protects against - parasitic worms IgG: crosses the placenta for immunity to fetus provides most antibody based immunity IgM: expressed on B cells & secreted rapidly addresses early stages of response before specified responses produced

9. T cell activates when it encounters a B cell that displays it’s specific MHC & fragmented pathogen complex T LYMPHOCYTES (T cell) originates in bone marrow THYMUS produces a precursor cell some TYPES: HELPER : activation, rapid dividing & secretion (cytokines) – regulate/ help immune response CYTOTOXIC : destroy virus infected/ tumour cells - cause of transplant rejection MEMORY : persists after infection has subsided - quick action if activated by their MHC coagent REGULATORY : closes response of subsided infection NATURAL KILLER : destroys virus infected/ tumour cells

10. immune COMMUNICATION is AIDED VIA: - MHC (major histological complex) - cytokines : interleukins

11. CELL SURFACE RECEPTORS: MHC PROTEINS MHC : called the > major histological complex FUNCTION: attracts specific cells consists of genomic material - proteins are coded with this & expressed on cell’s outer surface after B cell has fragmented the PATHOGEN … B cell then “ expresses ” these fragments in a complex : to attract the T-cell via the use of the MHC complex (Wikipedia, 2008)

15. Bibliography HON Foundation. (2002). HON allergy glossary antigen - presenting cell (APC) . Retrieved October 21, 2008, from https://www.hon.ch/Library/ Theme/Allergy/Glossary/apc.html - 11k - Wikipedia. (2008). B cell – wikipedia, the free encyclopedia . Retrieved October 21, 2008, from http//: en.wikipedia.www. org/wiki/ B _cell - 75k - Wikipedia. (2008). T cell – wikipedia, the free encyclopedia . Retrieved October 21, 2008, from http//: en.wikipedia.www. org/wiki/ T _cell - 59k - Wikipedia. (2008). Cytokine – wikipedia, the free encyclopedia . Retrieved October 21, 2008, from http//: en.wikipedia.www. org/wiki/ Cytokine - 118k -

16. Wikipedia. (2008). Interleukin – wikipedia, the free encyclopedia . Retrieved October 21, 2008, from http//:en.wikipedia.www. org/wiki/ Interleukin - 89k - Wikipedia. (2008). Major histocompatibility complex – wikipedia, the free encyclopedia . Retrieved October 21, 2008, from http//:en. wikipedia.www. org/wiki/Major_histocompatibility _ complex - 69k - Wikipedia. (2008). Antibody – wikipedia, the free encyclopedia . Retrieved October 21, 2008, from http//:en.wikipedia.www. org/wiki/ Antibody - 192k - Crudup A. B. (n.d). Primary and secondary immune responses . Retrieved October 21, 2008, from http//: www.meredith.edu/kenya/prim_ secon_immune_ response s.pdf -