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Disease and Responses
In order for a pathogen to cause harm it must enter our bodies we have a number of
primary defence mechanisms to prevent this
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Which are produced by mitosis at the base of the skin and work their
way up to the surface then dry out (cytoplasm is replaced by keratin) this is known as
the keratinisation
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These areas are protected by mucus where the
pathogens stick to the mucus and the goblet cells and the cilia come into play
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Phagocytes
There are two types of Phagocyte:
1
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Also they travel through the blood and
can be released in large numbers as a result of infection
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Macrophages are larger and also made in the bone marrow
and travel in the blood as monocytes
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Phagocytes engulf and destroy pathogenic cells
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II
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IV
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VI
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Foreign cells are recognised by the antigens on their surface
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Phagocytes also have receptors that bind to the antibodies
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Lysosomes then fuse with the phagosome and release enzymes into it called lysins
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Infected cells release chemicals like histamine that attract Neutrophils
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Antibodies are produced by lymphocytes and are released due to
an infection
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Each antigen has a specific
antibody which will make the antigen harmless by attaching to it
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The constant region is the same in all antibodies and enables phagocytes to attach to
the antibody
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To ensure that the
antibody can only attach to a specific antigen
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The antigen can also be used for the pathogen to bind to its host cell however if it’s
antigens are blocked by antibodies then it cannot do this, this is called neutralisation
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Secondary Response: This is a lot faster than the primary response as the immune
system can swing into action a lot faster as it already knows this type of pathogen
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Cell Signalling is the communication between cells that allows effective coordination of a
response
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1)
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3)
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5)
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Firstly the pathogens are detected by our body cells
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Part of the pathogen the attach to the plasma membrane
This can then act as a distress signal for cells of the immune system to detect or it
can act as a marker to say that the host cell is infected
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The macrophages the engulf and digest the pathogen in the lymph nodes
The antigens are then separated out and put into a cell surface molecule
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Its function is to find the lymphocytes that can neutralise that particular antigen
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T cells, B cells and macrophages can produce interleukins which can stimulate
differentiation of B and T cells
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