Question

The figure below represents die internal structure of a mammalian heart and the associated blood vessels.

(i) (a) Name each of the structures labeled 1, 2, 3, 4, 5, 6, 7 and 8.

(b) State the function of each of the structures 5, 6, 7 and 8.

(ii) (a) State the function of heart as an entire organ.

(b) Why are the walls of the left ventricle more muscular than the right ?

Answer 1

(i) (a) 1. Right auricle,

2. Left ventricle,

3. Pulmonary artery,

4. Pulmonary vein,

5. Inferior vena cava,

6. Aorta,

7. Pulmonary semilunar valve,

8. Tricuspid valve.

(b) 5 — carry deoxygenated blood from the body parts to the right auricle of the heart.

6 — distributes blood all over the body.

7 — prevents the backflow of the blood into the ventricles.

8 — prevents the reverse flow of the blood from right ventricle into the right auricle,

(ii) (a) The heart makes the blood to circulate all over the body.

(b) The walls of left ventricle are more muscular because they have to pump blood to a larger distance than the right so that walls have to withstand a high pressure.