AS Biology: parts of immunity

Just some notes about white blood cells and how they help in immunity

  • Created by: Yasmin
  • Created on: 23-12-12 17:17

The different types

There are three types of white blood cells

Phagocytes - they are non specific

T-lymphocytes/ T-cells - part of the cell mediated responce

B-lymphocytes/ B-cells - part of the humoural responce

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The stages of phagocytosis

1) Chemoattractants attract the phagocyte to the pathogen.

2) The phagocyte engulfs the pathogen.

3) The phagocyte traps the pathogen in a vesicle.

4) Lysosomes fuse with the vesicle.

5) The lysosome puts lysosomial enzymes on the pathogen.

6) The pathogen is digested.

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This is the cell mediated responce:

1) The infected cell displayes the pathogens antibodies on it's cell.

2) A t-cell with a receptor that is complementary to the antibody binds.

3) The t-cell then divides by mitosis.

These t-cells then do these things

  • Make a protien which makes holes in the infected cell's cell surface membrane
  • Make memory cells
  • Stimulate the production of b-cells.
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This is part of the humoral responce

1) A b-cell with a complementary antigen to the pathogens antibody bind to form an antigen-antibody complex

2) B-cells then divide by mitosis

3) They then become plasma cells which release antibodies that destroy pathigens + their toxins

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