Natural Immunity
used snaprevise to get infomation
- Created by: gsemma
- Created on: 30-04-19 16:39
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- Natural Immunity
- defence mechanisms
- specific
- cell-mediated response
- T-lymphocytes
- recognise antigens presented on plasma membrane of foreign cells
- 1. pathogen invades cell or phagocytes takes it up
- 2. antigens presented on cell or phagocyte
- 3. receptors on specific T-helper cells fit the antigens which activates them to undergo rapid mitosis to produce lots of clones.
- 4. these then activate
- cytotoxic t-cells
- kill abnormal cells by producing a protein called perforin which makes holes in membrane so cell dies.
- develop into memory cells
- stimulate b-cells to divide or phagocytosis in phagocytes
- cytotoxic t-cells
- 4. these then activate
- 3. receptors on specific T-helper cells fit the antigens which activates them to undergo rapid mitosis to produce lots of clones.
- 2. antigens presented on cell or phagocyte
- T-lymphocytes
- humoral response
- B-lymphocytes
- complementary to antigen on pathogen
- clonal selection
- 1. antigen enters B-cell by endocytosis
- 2. B presnts antigen
- t binds and simulates b to undergo rapid mitosis
- large number of B clones with same shaped antibody
- t binds and simulates b to undergo rapid mitosis
- 2. B presnts antigen
- 1. antigen enters B-cell by endocytosis
- clonal selection
- cells produced from clonal selection
- plasma cells- shorted lived and produced by antibodies (2000 per sec). primary response
- memory cells- long lived and remain dormant until next invasion. rapidly divide in secondary response.
- complementary to antigen on pathogen
- B-lymphocytes
- cell-mediated response
- non-specific
- physical barriers
- phagocytosis
- phagocytes
- WBCs that engulf pathogens and kill them
- 1. phagocyte engulfs the pathogen and membrane folds inwards- phagocytosis
- 2. pathogen trapped in phagocyte
- 3. lysosomes bind and release lytic enzymes to digest the pathogen
- 4. now harmless, absorbed/released
- 3. lysosomes bind and release lytic enzymes to digest the pathogen
- 2. pathogen trapped in phagocyte
- phagocytes
- antigens
- proteins on membrane
- used to identify foreign cells form self-cells
- foreign? immune response
- antibodies
- structure
- diagram
- function
- form antibody-antigen complexes
- opsonisation
- act as binding site for phagocytes
- binding can prevent pathogen entering cells.
- less specific opsonin's stick to molecules not found in host
- agglutination
- each molecule has to bonding sites so can crosslink by binding to two different pathogens.
- leads to clumping which impedes the pathogen making it easier for phagocytosis
- particularly effective against viruses.
- each molecule has to bonding sites so can crosslink by binding to two different pathogens.
- opsonisation
- form antibody-antigen complexes
- structure
- specific
- defence mechanisms
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