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21 Cards in this Set
- Front
- Back
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First Line of Defence |
preventing entry of pathogens into the body |
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First Line of Defence |
- INTACT skin - mucous membranes - lysozyme in tears - stomach acid - natural flora such as bacteria |
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Second Line of Defence |
a non-specific response to pathogens that evades the first line of defence |
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Third Line of Defence |
highly specific immune response to a pathogen that has evaded the first line of defence |
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How does the body know if it is a pathogen or not?
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self markers, if the cell has a different marker than one the body recognises, it will be destroyed |
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Hypersensitivity |
- immunological response to antigen - mast cells release histamines |
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Phagocytes (macrophages) |
engulf foreign material by endocytosis (takes it in via bulk transport) and destroy it using lysosomes and enzymes in the cell to break it down. |
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phagocytes (cont.) |
- type of white blood cell - phagocytosis - surround foreign material - engulf and destory |
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phagocytosis |
-detection -ingestion -phagosome forms -fusion with lysosome -digestion -discharge |
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natural killer cells |
find body cells that have non-self markers and destroy them by punching holes in membrane or signalling the cell to kill itself via apoptosis |
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interferon |
group of proteins released by infected cells to make other cells more resistant to viral infection |
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complement proteins |
- made in liver - 20 different types 3 main actions: 1. cause lysis of microorganisms 2. stick to foreign matter, allowing them to be more identifiable 3. attract, stimulate phagocytes |
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cytokines (signalling molecule) |
small proteins secreted by specific cells of immune system, carry signals locally between cells and thus have an effect on other cells, i.e. producing certain chemicals etc. |
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platelets |
- small amounts of cytoplasm surrounded by membrane - plug breaks in blood vessels - blood clotting |
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dendritic cells |
stimulate specific immune system by displaying antigens on their membranes |
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inflammation |
- brings more blood to area - chemicals released by mast cells etc - large number of phagocytes carried in blood to infected area - phagocytes engulf bacteria and destroy with enzymes from lysosomes - pus forms as a result of dead white blood cells and digested foreign matter |
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blood clotting |
1. platelets adhere to wounded area and release chemicals that attract other platelets to the area to form a plug 2. fibrin attaches to the platelet plug to mesh it all together and strengthen the seal 3. wounded tissue healed over time and the clot is dissolved |
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MHC markers |
molecules that mark a cell as self are encoded by a group of genes known as the major histocompability complex |
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MHC I markers |
- all cells with a nucleus - macrophages, dendretic cells, B cells - show antigen to cytotoxic T cells |
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MHC II markers |
antigen presenting cells such as macrophages and dendritic cells, also B cells - show antigens to helper T cells |
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antigen presenting cells |
- macrophages and dendritic cells - if a particle does not have a self marker then microphages and dendritic cells with engulf it and present the antigen on their MHC II markers |
