The Circulatory System

Question 1

Describe the order of structures in which blood flows through the heart.

Answer 1

1. Vena cava
2. Right atrium
3. Right atrioventricular valve
4. Right ventricle
5. Right semi-lunar valve
6. Pulmonary artery
7. Pulmonary vein
8. Left atrium
9. Left atrioventricular valve
10. Left ventricle
11. Left semi-lunar valve
12. Aorta

Question 2

What is the role of the septum?

Answer 2

The septum separates the two halves of the heart

Question 3

Describe the muscle thickness of the atria.

Answer 3

• atria have thin muscular walls
• as they contract less forcefully
• causing a lower increase in pressure
• as blood is needed to be pushed a short distance into the ventricles

Question 4

Describe the muscle thickness of the ventricles.

Answer 4

• ventricles have thick muscular walls
• so contract more forcefully
• causing a higher increase in pressure
• as blood is needed to be pushed a longer distance

Question 5

What is the role of the valves?

Answer 5

Valves open to allow blood flow in one direction then close to prevent back flow.