Question

State whether the following statements are true or false. The first heart sound results from a closure of semilunar valves.
a. True
b. False

Answer 1

Hint: Heart sounds seem to be the noises caused by the heart beat and the subsequent blood flowing through it. Explicitly, the noises reflect the friction caused when the heart valves snap shut. A stethoscope is used to listen to such unique and distinct tones which provide considerable auditory information about rhythm of the heart.

Complete answer:
The heart produces two sounds in a healthy individual which are usually known as lub and dub. The 3rd and 4th sounds are produced in certain healthy peoples but can signify heart function impairment. The first and second sound of the heart are produced by the contraction of the atrioventricular and semilunar valve respectively. Heart mutterings may be affected by several different cardiovascular complications, the murmurs may change markedly with severity of cardiac disease. At the point at which the pulmonary artery and the aorta exit the ventricles the semilunar valves are attached which are pocket like structures. The orifice between both the right ventricle and the left artery is secured by the pulmonary valve. The aortic valve seals the orifice between the aorta as well as the left ventricle. The semilunar valve allows blood to be forced into the arteries, but also prevents the backflow into the ventricles from arteries.

Hence, the correct answer is option (B). As the first heart sound is produced due to the closure of the tricuspid and bicuspid valves at the beginning of systole i.e Lub.

Additional information:
Mostly an intelligent doctor can diagnose cardiac conditions with some specificity mainly based on murmur, accompanying physical examination, and experience with the frequency of multiple heart issues. The heart muscle receives little blood during a cardiac arrest because one or more arteries feeding the muscle are damaged and unable to deliver sufficient blood flow and the cardiac requirement is greater than the available cardiac supply. Heart rhythm complications arise when your heartbeats are not properly coordinated by electrical impulses causing the heart to beat too fast, too slow or irregular.

Note: The number of times the heart beats per minute is the heart rate. For an individual a standard or healthy heart rate is between 60 and 100 bpm (beats per minute). The lower your pulse rate the more effective your heart is at functioning. One cardiac cycle requires 0.7 seconds.