Dear student,
The three kinds of blood vessels of human circulatory system are arteries, veins and capillaries. Their functions are as follows:
| Arteries | Veins | Capillaries |
1. | 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.
|
2. | 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.
|
3. | Valves are absent.
| Valves present to prevent back flow of blood.
| No valves are found
|