Types of Vessels - Veins
Biology: Cambridge International GCSE Supplement, topic 9.3.2
Veins
Veins form when capillaries join up after passing through the body. They transport deoxygenated (contains no oxygen) blood (apart from the pulmonary vein) from the organs back to the heart.
Thinner walls than arteries
- The walls are thinner than those found in the arteries as the blood is at a lower pressure.
Wider cross section than arteries
- Low pressure hinders blood flow. This means that veins have a wider cross section through which blood can flow to counteract this.
Valves
- Veins have valves to prevent the backflow of blood.
Venules
- Venules connect capillaries to veins.
Test yourself on Types of Vessels - Veins
Why do veins have valves?
Which is the only type of vein that carries oxygenated blood?