Page 14 - 新思维科学学生用书6 样章

1.1 The circulatory system

Each kind of blood vessel has a different structure and function in the body.
The blood vessels run from the heart to the lungs, around the body and back to

the heart. Blood always moves along the same pathway in the blood vessels.

• The heart pumps blood in

arteries to the lungs to pick Capillaries – join arteries
up oxygen. Artery – carries blood and veins. Very narrow
with thin walls to allow
containing food and
• The oxygen-rich blood oxygen away from the substances like oxygen

travels back in veins from heart to the body and food to move
through them
the lungs to the heart. These
Small artery
are the only veins that carry Small vein

blood with oxygen.
• The heart pumps the

oxygen-rich blood in other

arteries to the rest of
the body.

• The blood from the rest of the
Thick elastic
body, which is now low in muscular wall Thin elastic

oxygen, travels back to the muscular wall

heart in veins.
Vein – carries blood containing
Questions wastes, such as carbon dioxide,
from the body towards the heart
1 a What does the heart do?

b Why does it do this?

2 What is a heartbeat?
3 Why does the heart pump blood to the lungs before it pumps blood to the rest of

the body?

4 Why do we need three different types of blood vessels?
5 Describe to your partner the pathway of blood around the body. Make a cycle

diagram to show this pathway.

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