How could the heart compensate for an increase in flow rate to maintain blood pressure?

How could the heart compensate for an increase in flow rate to maintain blood pressure?

• A. By decreasing the heart rate.
• B. By reducing venous return.
• C. By increasing the heart rate (and possibly stroke volume) to pump more blood.
• D. By decreasing stroke volume.

Answer: (C)

When the body needs more blood flow, the heart raises its output to keep arterial pressure from falling. It does this primarily by increasing heart rate, which adds more beats per minute, and also by increasing how much blood is pumped with each beat (stroke volume) when possible. This rise in cardiac output helps maintain mean arterial pressure even as demand goes up. If heart rate were reduced, or preload and stroke volume were decreased, cardiac output would fall and blood pressure would tend to drop. So the best response is to speed up the heart and, if feasible, pump more blood with each beat.

When the body needs more blood flow, the heart raises its output to keep arterial pressure from falling. It does this primarily by increasing heart rate, which adds more beats per minute, and also by increasing how much blood is pumped with each beat (stroke volume) when possible. This rise in cardiac output helps maintain mean arterial pressure even as demand goes up. If heart rate were reduced, or preload and stroke volume were decreased, cardiac output would fall and blood pressure would tend to drop. So the best response is to speed up the heart and, if feasible, pump more blood with each beat.