Question

Differentiate between the following pairs on the basis of what is mentioned within brackets:

(i) LUB and DUB (names of the valves whose closure produce the sound)

Answer 1

Heart sound:

During the cardiac cycle, the heart produces a special type of LUBB-DUPP sound. This sound is known as heart sound.

LUBB:

1. It is the first heart sound.
2. It is caused by the closure of the mitral and tricuspid valves.

DUPP:

1. It is the second heart sound.
2. It is a sharp and short sound.
3. It is caused by the closure of the aortic and pulmonary valves (semilunar valves).

LUBB sound	DUPP sound
It is the first heart sound.	It is the second heart sound.
2. It is caused by the closure of the mitral and tricuspid valves.	2. It is caused by the closure of the aortic and pulmonary valves.