Which of the following describes the stroke volume (SV)?

Question

A. The difference between the end-diastolic volume (EDV) and the end-systolic volume (ESV)

B. Inversely proportional to contractility

C. The stretch of cardiomyocytes at the end of diastole

D. Fraction of the blood being pumped by the ventricles during each contraction

Answer 1

he correct answer is A. The stroke volume (SV) is the difference between the end-diastolic volume (EDV) and the end-systolic volume (ESV). It represents the volume of blood ejected from the ventricles with each heartbeat.

In more detail:

A. The stroke volume (SV) is the amount of blood pumped out of the heart's left ventricle during each contraction. It is calculated by subtracting the end-systolic volume (ESV) from the end-diastolic volume (EDV). This answer accurately describes the SV.

B. The statement that SV is inversely proportional to contractility is incorrect. Contractility refers to the strength of the heart's contraction, and it affects stroke volume positively. Increased contractility leads to increased stroke volume, and decreased contractility leads to decreased stroke volume.

C. The statement about the stretch of cardiomyocytes at the end of diastole is referring to preload, not stroke volume. Preload is the amount of stretch on the heart muscle fibers just before contraction and is related to the end-diastolic volume (EDV). It influences the stroke volume but is not a direct definition of it.

D. The statement about the fraction of the blood being pumped by the ventricles during each contraction is a broad description of the ejection fraction, not specifically stroke volume. The ejection fraction is the percentage of blood ejected from the ventricles during each contraction compared to the total amount of blood in the ventricles at the beginning of the contraction. Stroke volume is the specific measurement of the volume of blood pumped out, not as a fraction or percentage.

Answer 2

Option A describes the stroke volume (SV) accurately. Stroke volume is defined as the difference between the end-diastolic volume (EDV), which is the volume of blood in the ventricles at the end of diastole (the relaxation phase), and the end-systolic volume (ESV), which is the volume of blood remaining in the ventricles at the end of systole (the contraction phase).

Stroke volume is the amount of blood ejected from the ventricle with each cardiac cycle. It can be readily calculated by subtracting the end-systolic volume from the end-diastolic volume. Multiplying the stroke volume by the heart rate yields the cardiac output, typically reported in liters per minute.

https://youtu.be/hpQFToprlH8?t=55

Answer 3

The correct answer is A. The stroke volume (SV) is the difference between the end-diastolic volume (EDV) and the end-systolic volume (ESV). It represents the volume of blood ejected from the ventricles with each heartbeat.

In more detail:

A. The stroke volume (SV) is the amount of blood pumped out of the heart's left ventricle during each contraction. It is calculated by subtracting the end-systolic volume (ESV) from the end-diastolic volume (EDV). This answer accurately describes the SV.

B. The statement that SV is inversely proportional to contractility is incorrect. Contractility refers to the strength of the heart's contraction, and it affects stroke volume positively. Increased contractility leads to increased stroke volume, and decreased contractility leads to decreased stroke volume.

C. The statement about the stretch of cardiomyocytes at the end of diastole is referring to preload, not stroke volume. Preload is the amount of stretch on the heart muscle fibers just before contraction and is related to the end-diastolic volume (EDV). It influences the stroke volume but is not a direct definition of it.

D. The statement about the fraction of the blood being pumped by the ventricles during each contraction is a broad description of the ejection fraction, not specifically stroke volume. The ejection fraction is the percentage of blood ejected from the ventricles during each contraction compared to the total amount of blood in the ventricles at the beginning of the contraction. Stroke volume is the specific measurement of the volume of blood pumped out, not as a fraction or percentage.