7.3 - Heart Structure

Question 1

Why is the left ventricle wall thicker than the right ventricle wall?

Answer 1

The left ventricle has a thicker wall with more muscle than the wall of the right ventricle.

This is because:

1. The right ventricle only needs enough pressure to pump deoxygenated blood a short distance to the lungs.
2. The left ventricle needs a lot of pressure to pump oxygenated blood to the other more distant organs of the body.

Question 2

Why are the ventricle walls thicker than the atria?

Answer 2

The ventricles have thicker walls with more muscle than the atria.

This is because:

1. The atria only need enough pressure to pump blood a short distance into the ventricles.
2. The ventricles need a lot of pressure to pump blood a long distance out of the heart to other organs.

Question 3

Blood vessels associated with the heart (4):

Answer 3

1. The pulmonary vein- This moves oxygenated blood into the left atrium from the lungs.
2. The aorta- This moves oxygenated blood from the left ventricle to the body.
3. The vena cava- This moves deoxygenated blood into the right atrium from the body.
4. The pulmonary artery - This moves deoxygenated blood from the right ventricle to the lungs.

Question 4

Function of valves

Answer 4

There are valves in the heart that prevent backflow of blood in the wrong direction.

Question 5

Valves within the heart (2):

Answer 5

The atrioventricular valves:

• The tricuspid valve is located between right atrium and right ventricle.
• The bicuspid (mitral) valve is located between left atrium and left ventricle.
• Both valves prevent backflow of blood into the atria when the ventricles contract.

The semi-lunar valves:

• These are located between the ventricles and the pulmonary artery and the aorta.
• They prevent the backflow of blood into the ventricles when they relax.

Question 6

How are the two sides of the heart separated?

Answer 6

The septum separates the two sides of the heart, preventing oxygenated and deoxygenated blood from mixing.

Question 7

Why does the blood have two separate pumping mechanisms?

Answer 7

• Blood pressure drops in the lungs as it flows through the capillaries.
• A single pump would slow the blood flow to the body cells.
• Two pumps increase the pressure before the blood circulates.

Question 8

Difference between atria and ventricles

Answer 8

• Atria- The top chambers in the heart that collect blood from blood vessels (veins).
• Ventricles- The bottom chambers in the heart that pump blood into blood vessels (arteries).