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What 2 lines of defence does the immune system provide against pathogens?
Preventing entry of pathogens into body, killing pathogens that get into the body
How does the skin prevent the entry of pathogens?
Skin flora make it difficult for pathogens to become established, when the skin is broken blood clots forming a scab sealing the gap
What is skin flora?
Community of microorganisms that live naturally on the skin
What body parts prevent infections?
Eyes, Nose, Trachea and bronchi, Stomach
How do eyes prevent infection?
Produces tears which contain enzymes -> chemical barrier
How does the nose prevent infection?
Has internal hairs -> physical barrier, Cell in nose produce mucus
How does the cells in nose that produce mucus prevent infection?
Trap pathogens before they enter lungs
How do the trachea and bronchi prevent infection? (Not Goblet)
Ciliated cells waft cilia and move mucus and pathogens up to throat where swallowed
How do the trachea and bronchi prevent infection? (Not Ciliated)
Goblet cells create mucus to trap pathogens -> physical barrier
How does the stomach prevent infection?
Hydrochloric acid kills pathogens from mucus, food or water -> chemical barrier
What causes an infection?
When pathogens pass through the non-specific first line of defence
What are the two types of white blood cells?
Phagocytes and lymphocytes
What do phagocytes do?
Ingest and digest microorganisms, attacks any foreign cell
Why do phagocytes ingest and digest?
They’re attracted to pathogens and bind to them
What do phagocytes do after binding to pathogens?
The cell membrane surrounds the pathogen and engulfs it
What happens after phagocytes’ cell membrane surrounds the pathogen?
Enzymes inside the cell break down the pathogen and destroy it
What do lymphocytes do?
Recognise foreign antigens on surface of pathogens -> produce specific antibody + antitoxin for particular pathogens
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