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In this topic of IBDP Biology, we will learn about the function of body defence mechanisms.
Defence Mechanisms
- Non-Specific - response is immediate and the same for all pathogens
- Physicial Barrier (e.g. skin)
- Phagocytosis
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- Specific - response is slower and specific to each pathogen
- Cell medidated response (T cells)
- Humoral response (B cells)
Antigens
- When it comes to IBDP Biology, any part of an organism or substance which is foreign (non self), and stimulates an immune response.
- They are usually proteins which usually are on the cell surface membranes of pathogens.
- Antigens are not always on the invading cell. You can have antigen-presenting cells which are cells from the immune system which take the pathogen's antigens and allow the functions of the immune system to work.
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Lymphocytes
When it comes to IBDP Biology, lymphocytes are white blood cells. There are two types of lymphocytes:
- T lymphocytes (T cells)
- mature in the thymus gland
- associated with cell mediated immunity
- B lymphocytes (B cells)
- mature in the bone marrow
- associated with humoral immunity
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Cell Mediated Immunity/Humoral Immunity
- Cell mediated immunity- immunity with body cells involving T cells
- Humoral immunity- immunity with bodily fluids involving B cells
This is the end of this topic
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