Practice Questions

1.State the names of the three blood vessels present in animals.

Arteries, Veins and Capillaries

2. Describe how the structure of an artery is different to that of a vein

Arteries lack valves, have thicker walls, more muscle and elastic tissue, narrow lumen

Veins have valves, thinner walls, less elastic fibres and muscle tissue, wide lumen.

3. Why do veins need valves?

To prevent the backflow of blood, due to low blood pressure