Question

What is the stroke volume of the adult human heart?
A) 50 ml
B) 70 ml
C) 90 ml
D) 100 ml

Answer 1

Hint: Stroke volume is the volume of the blood pumped from the left ventricle per beat. The stroke volume for each ventricle is equal.

Complete Answer:
- Human heart has two auricles and two ventricles. The stroke volume is the volume of blood pumped from the left ventricle per beat. It is calculated by using the measurements of ventricle volume from echocardiogram and subtracting the end systolic volume from end diastolic volume.
- The stroke volume can be applied to either of the ventricles but it is usually referred to the left ventricle. It determines the cardiac output. The cardiac function is dependent on the stroke volume.
- Stroke volume of a normal healthy heart is 70 ml. It decreases in certain conditions like in disease state.
- The stroke volume is raised due to high intracellular calcium ions, thyroid hormones, glucagon, epinephrine and nor-epinephrine, prolonged aerobic exercise. Stroke volume is lowered by parasympathetic stimulation, hypoxia, hyperkalemia.
- Men have larger heart size as compared to women. So the stroke volume of men is comparatively higher than that of women.

Thus the correct answer is (B). The stroke volume of the human heart is 70 ml.

Note: Stroke volume tells us about the proper functioning of the heart. It is lowered in case of disease. Men have greater stroke volume than women due to larger hearts.