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3. Body DefensesSkin, Mucus, & White Blood

Cells

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There are bacteria and viruses all around you, yet you are healthy most of

the time

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This is true because your body has ways to protect you

The body’s first line of defense is the skin

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The skin keeps bacteria and viruses from getting into the body

If you cut your skin, then bacteria and viruses can get into the body through

the cut

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But your body can still defend itself by using its white blood cells

White blood cells are in your blood so is always moving throughout your body

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When you are cut, more white blood cells move to the area to destroy

bacteria

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Vocabulary:

White blood cells

A part of the blood that help the body fight germs that cause disease

When the white blood cells destroy the bacteria, the skin around the cut gets

red

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There may be pus in the cut which is a sign that the white blood cells are

working

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Vocabulary:

pus

Whitish fluid that oozes from a wound that is made of dead bacteria and white

blood cells

If you do cut yourself, try to keep bacteria from getting into your body

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Wash the area around the cut to get rid of the bacteria on your skin

If the cut is deep, see a doctor as you might need to have stitches to hold the

cut together while it heals

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Bacteria or viruses can get into your body when you breathe

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Your body has another way to defend you

Your nose and throat are lined with tissues that make a liquid called mucus

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Vocabulary:

mucus

A sticky liquid made in the tissues that line the nose and throat

The sticky mucus traps many bacteria and viruses

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Then the bacteria and viruses leave the body in a cough or a sneeze

The tissues in the nose and throat also have tiny hairs

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These hairs sweep mucus and particles up toward the mouth to be swallowed

so no harm is done to the body

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