blood vessels

Question 1

what do the arteries do?

Answer 1

Carry blood AWAY
from the heart. They
stretch as blood is forced
through them. They have
thick walls containing
muscle and elastic fibres.

Question 2

what do veins do?

Answer 2

Carry blood
TOWARDS the heart. They
have thinner walls and
valves to prevent backflow.

Question 3

what do capillaries do?

Answer 3

Network of tiny
vessels linking arteries and
veins. Very thin for
diffusion of substances.

Question 4

Why is it called a double
circulation system?

Answer 4

One transport system
carries blood from the
heart to the lungs and back
again.

The second carries the
blood from the heart to all
the organs of the body and
back again.