Question

The rhythmic contraction and relaxation of heart muscles makes a
A. Heart stroke
B. Heart rate
C. Heartbeat
D. None of the above

Answer 1

Hint: It is the same as the pulse rate, and the heart contraction is detected in the form of pulsations in some places such as the wrist, and this is called the pulse rate.

Complete step by step answer:
First we should know about cardiac muscles to answer this question. The cardiac muscle, also said as the myocardium, is located only in the heart of vertebrates, one of three main forms of muscle. Cardiac muscle, another major type of muscle, is identical to skeletal muscle in that it has contractile units said as sarcomeres; this feature, however, also separates it from smooth muscle, the third type of muscle. The muscle of the heart distinguishes from the muscle of the skeleton in that it has rhythmic contractions and is not under voluntary control. Cardiac muscle rhythmic contraction is controlled by the heart's sinoatrial node, which acts as the pacemaker of the heart.
Now, let us find the solution from the options-
- When blood supply to a portion of the heart is interrupted, normally by a blood clot, heart stroke occurs. The cardiac muscle continues to die without oxygenated blood. Thus, the option A is incorrect.
- The number of times your heart beats per minute is the heart rate. Thus, the option B is incorrect.
- The rhythmic contraction and relaxation of the muscles of the heart is due to the heartbeat. One heartbeat comprises one contraction (systole) and one heart relaxing (diastole).

Thus, the correct answer is C.

Note:
The cardiac cycle is the word used to describe the relaxing and contraction that takes place as the heart functions via the body to pump blood. A term used to characterise the frequency of the cardiac cycle is heart rate. It is called one of the four vital signs and is a vector that is controlled. The heart rate is generally measured as the number of heart contractions (heartbeats) in a minute and represented as "beats per minute" (bpm).