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White celi warriors

White blood cells target pathogens in a number of ways. Macrophages, for example, are white blood cells that have left the blood vessel in search of bacterial infections. They engulf bacteria and kill the ingested pathogen.

How to: heal a cut

01.

How does your body ~

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fight

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Your body has several lines of defence against pathogens, or germs. The skin forms a barrier to stop invading pathogens, while Chemicals in tears and acidic stornach juices also deter bacteria. Pathogens that do breach these defenses are targeted by white blood cells and other weapons of the immune (defense) system.

Types of pathogen

A

Virus

Infectious agent that invades and reproduces inside cells, causing diseases such as colds, chickenpox, and fiu.

A

Cft

Average life expectancy

35

Ancient Greece (c. 300 bce)

40

Industrial Revolution (1800s)

47.3

U.S.A. (1900)

31.8

Swaziland (2009)

64.7

India (2009)

82.6

Japan (2009)

Bacteria

Single-celled microscopic organisms that release toxins and cause diseases, such as food poisoning and sore throats.

Parasites

Organisms such as tapeworms that make the body their food source.

A

Stethoscope to listen to

heart and check that heartbeats sound strong and regular.

Release

histaminę to widen blood vessels and provide access* to white blood cells.

Fungi

Molds that infect the skin causing irritation, such as athlete’s foot.

Reflex hammer to test reflexes

in your nervous system and your spinał cord.

Plalelet_„ Lwhite

\J m Send white blood cells to destroy pathogens in the cut, and make platelets become sticky and group together.

OR \WHAT -

Tongue depressor to examine

the mouth and throat for signs of inflammation or infection.

How doctors make a diagnosis

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