Question

The instrument used to hear heartbeat is
A. Electrocardiograph
B. Sphygmomanometer
C. Stethoscope
D. Haemometer

Answer 1

Hint: Heartbeat is a two-part pumping action of the heart which is caused due to alternating contractions and relaxations of the myocardium. This action takes about a second to occur. It’s a cyclic rhythm which is also known as pulse.

Complete answer:
The heart which is the central part of the circulatory system serves as the pump to circulate blood. In the case of humans, it is a four-chambered double pump located between two lungs. The pumping of the heart is known as the heartbeat or pulse.
This heartbeat occurs due to alternating contractions and relaxations of the myocardium. The contractions are performed by the electrical impulses from the S-A node which is also known as a natural pacemaker and is located in the muscle of the right atrium. Due to an impulse from the S-A node, the two atria lead the blood into the ventricles. Impulses from the atrioventricular, or A-V node, which are located at the junction of the two atria regulate the contraction of the ventricles. After the contraction, the ventricles go into a relaxed condition. Blood again starts to move into the atria, and an impulse from the S-A node restarts the process. which is called the cardiac cycle. The relaxation period of ventricles is called diastole while the period of contraction is called systole. The diastole phase is longer in comparison to systole and it provides rest to the heart between contractions. Generally, the rate of heartbeat varies in different animals according to their size. In an adult human, the average rate of heartbeat is seventy per minute.
This heartbeat can be heard by an instrument called a stethoscope. Through a stethoscope, the sounds produced within the body due to the contractions and relaxations system of the heart can be easily detected. It is used as a medical instrument in detection of abnormalities in the working of the heart. It was discovered by the French physician R.T.H Laennec.
An electrocardiogram is used to check the heart's rhythm and electrical activity. The sphygmomanometer is a medical instrument used to measure and detect blood pressure. Haemometer is used to detect the amount of haemoglobin in the blood.

Therefore, the correct option is option C.

Note: Heartbeat is an action of the heart that occurs due to the pumping of blood at the time of contractions and relaxations of the myocardium. This takes a minute to happen and produces a little sound. That sound can be detected or heard by the medical instrument called a stethoscope.