List the three kinds of blood vessels of human circulatory system and write their
The three kinds of blood vessels of human circulatory system are arteries, veins and capillaries. Their functions are as follows:
Carry Oxygen rich blood from heart to all parts of the body.
Carry carbon di oxide rich blood from all parts of the body back to the heart.
Capillaries act as a link between arteries and veins.
Since blood flow is rapid and at high pressure they have thick elastic walls.
They have thin walls
Consists of just a single layer of endothelial cells.
Water and other small-molecule substances can pass through this wall.
Valves are absent.
Valves present to prevent back flow of blood.
No valves are found