How does the Frank-Starling curve affect stroke volume during exercise?
A) The increased venous return causes cardiac chambers to increase in size and thus contract with more force
B) The increased sympathetic stimulation causes the heart to be faster with smaller stroke volumes
C) The Frank-Starling curve is only activated when the heart rate reaches 90% of the maximum targeted rate
D) The Frank-Starling law only affects heart rate, not stroke volume

Question

Quizplus · Accepted Answer

The Frank-Starling curve states that as the volume of blood in the heart (venous return) increases, so does the force of contraction of the cardiac muscle fibers, resulting in an increased stroke volume. During exercise, there is increased venous return due to increased blood flow to the muscles, causing the cardiac chambers to increase in size and contract with more force, resulting in an increased stroke volume. Option B is incorrect as sympathetic stimulation would increase heart rate and stroke volume. Option C is incorrect as the Frank-Starling curve is activated at all heart rates, not just when it reaches 90% of the maximum targeted rate. Option D is incorrect as the Frank-Starling law affects both heart rate and stroke volume.

How Does the Frank-Starling Curve Affect Stroke Volume During Exercise