Question

Veins have valves but arteries do not. Why?

Answer 1

1. Valves are muscular flaps that are located on each end of the two ventricles (lower chambers of the heart).
2. The valves prevent the backward flow of blood.
3. They act as one-way inlets of blood on one side of a ventricle and one-way outlets of blood on the other side of a ventricle.
4. Arteries don't require valves because pressure from the heart is so strong that blood is only able to flow in one direction.
5. Unlike arteries, veins contain valves that ensure blood flows in only one direction.
6. Valves also help blood travel back to the heart against the force of gravity.