Page 23 - 新思维科学学生用书6 样章

1 The human body

Continued

Questions

1 When you breathe in, does your chest get bigger or smaller?

Why do you think this is so?
2 When you breathe out, does your chest get bigger or smaller?

Why do you think this is so?

3 Explain how we are able to blow up a balloon.

Breathing

We need oxygen to live. When we breathe in, oxygen gas from

the air moves into the blood vessels in the lungs. Blood carries the

oxygen to the heart and then to the other parts of the body.
As your body uses up oxygen, it makes carbon dioxide. The blood

carries the carbon dioxide back to the lungs. We get rid of carbon

dioxide in the air we breathe out.

Air enters the
body through the Air leaves the body
nose or mouth through the nose or
mouth
The air goes down Air from the lungs
the windpipe and moves up the
into the lungs windpipe windpipe

The ribs move The ribs move
upwards and downwards
outwards and inwards

The chest gets The chest gets
bigger and the diaphragm smaller and air is
lungs fill with air pushed out of
the lungs
The diaphragm The diaphragm
muscle contracts muscle relaxes
and moves and moves
downwards upwards

breathing in breathing out

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