Key area 4.1 Non-specific defences

Question	Answer
Non-specific defences 1st line of defence	Physical and chemical defences Epithelial cells form a physical barrier and produce secretions against infrcetion S.A.M Skin - physical barrier Acid - kills microbes that are swallowed Mucus - traps microbes and sweeps them away from the lungs
Non-specific defences 2nd line of defence Inflammatory responce	Mast cells release histamine which causes blood vessels to vasodilate (become wider) and capillaries to become more permeable. The increased blood flow and secretions of cytokines leads to an accumulation of phagocytes and the delivery of antimicrobial proteins and clotting elements to the site of infection.
Non-specific defences 2nd line of defence Natural killer cells (NK cells)	Induce the viral infected cells to produce a self-destructive enzyme in a process called APOPTOSIS
Cytokines	Are "cell signalling" proteins which stimulate movement of cells towards the infected site. Results in accumulation of phagocytes and the delivery of antimicrobial proteins and clotting elements.
Non-specific defences 2nd line of defence Phagocytosis	A process where pathogens are engulfed and destroyed

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	Created by Dayna Underwood about 8 years ago