Human Defences and the Immune System

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What defences does the human body have to protect itself from pathogens?
Physical and Chemical barriers
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What are some examples of Physical barriers?
Skin that is too think for pathogens to pass through and mucus that traps pathogens in the breathing passages and lungs. Cilla in the lungs move mucus and trapped pathogens out of the lungs to the back of the throat where it's swallowed.
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What are some examples of Chemical barriers?
Lysozyme enzymes in tears kill bacteria by digesting their cell walls. This is also present in saliva and mucus. Hydrochloric acid in the stomach kills pathogens in food and drink.
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What is the immune system's job?
To help protect the body by attacking pathogens if they manage to enter the body. Lymphocytes are part of this immune system.
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What are antibodies and how do they work?
The antibodies procuced by a white blood cell are specific for one particular kind of pathogen. This means they can only destory that kind of pathogen. They can't destroy another kind of bacterium or virus.
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Other cards in this set

Card 2

Front

What are some examples of Physical barriers?

Back

Skin that is too think for pathogens to pass through and mucus that traps pathogens in the breathing passages and lungs. Cilla in the lungs move mucus and trapped pathogens out of the lungs to the back of the throat where it's swallowed.

Card 3

Front

What are some examples of Chemical barriers?

Back

Preview of the front of card 3

Card 4

Front

What is the immune system's job?

Back

Preview of the front of card 4

Card 5

Front

What are antibodies and how do they work?

Back

Preview of the front of card 5

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