Question

Give scientific reasons for the following statement:

Veins have valves present in them.

Answer 1

Veins:

1. Veins are blood vessels that carry deoxygenated blood to the heart from various parts of the body.
2. An exception is pulmonary veins which carry oxygenated blood from the lungs to the heart.

Veins have valves present in them:

1. Blood flows through veins under low pressure and due to this, there is a risk of backflow of the blood.
2. Thin pocket-shaped valves are present in veins.
3. Blood flows towards the heart when the valves are open, and when the valves are in a closed position the blood cannot flow back towards the legs.
4. In this way, these valves ensure the unidirectional flow of blood.