Question

The diagrams given below show the cross-section of two kinds of blood vessels:

(i) Identify the blood vessels A and B. In each case give a reason to support your answer.
(ii) Name the parts numbered 1 and 2.
(iii) When are the sounds “LUBB” and “DUB” produced during a heartbeat?
(iv) Name the blood vessel that
(a) begins and ends in capillaries.
(b) supplies blood to the walls of the heart.

Answer 1

(i)
A—Artery
B—Vein, because in A lumen is narrow, in B lumen is wide.
(ii) 1 —> Endothelium, 2 —> Lumen.
(iii) Lubb is produced when the ventricles contract and atrioventricular valves get closed at the beginning of ventricular systole.
Dub is produced by the closure of semilunar valves at the beginning of ventricular diastole.
(iv) (a) Portal system
(b) Coronary arteries