1. Tardigrade
  2. Question
  3. Biology
  4. Read the following four statements ( text1-4.) (1) The second heart sound is textDUB , which is associated with the closure of bicuspid and tricuspid valves. (2) The duration between consecutive second and first heart sound is text0.5 seconds in a cardiac cycle. (3) The heartbeat of a human increase when the adrenaline hormone is injected into it. (4) The atrial systole in a cardiac cycle increases the flow of blood into the respective ventricle by about text70 %. How many of the above statements are incorrect?

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Q. Read the following four statements $\left(\text{1-4.}\right)$
(1) The second heart sound is $\text{DUB}$ , which is associated with the closure of bicuspid and tricuspid valves.
(2) The duration between consecutive second and first heart sound is $\text{0.5}$ seconds in a cardiac cycle.
(3) The heartbeat of a human increase when the adrenaline hormone is injected into it.
(4) The atrial systole in a cardiac cycle increases the flow of blood into the respective ventricle by about $\text{70\%.}$
How many of the above statements are incorrect?

NTA AbhyasNTA Abhyas 2020Body Fluids and Circulation

Solution:

The second heart sound DUB is caused by the closure of the aortic valve and pulmonary valve at the end of ventricular systole or at the beginning of ventricular diastole. At the beginning of the atrial systole, about 70%-80% of the ventricles are normally filled; hence, during atrial contraction (atrial kick), the remaining 20%-30% gets filled.