Which of the following best describes the Bainbridge reflex?

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Multiple Choice

Which of the following best describes the Bainbridge reflex?

The concept here is the atrial (Bainbridge) reflex: when more blood returns to the heart, the walls of the right atrium stretch and trigger a reflex that increases heart rate. This response helps match the heart’s pumping to the greater venous return so cardiac output keeps up with the incoming blood. How it works: stretch receptors in the right atrium detect increased filling. Afferent signals travel to the medulla, activating pathways that raise heart rate by boosting sympathetic drive to the SA node and reducing parasympathetic tone. The net result is a faster heart rate to move the additional venous return onward through the circulation. The best description names the reflex itself as the mechanism behind the increase in heart rate with increased venous return. It’s not about a decrease in rate or no effect—the reflex specifically produces the rate rise in response to higher venous return, distinguishing it from other reflexes like the arterial baroreflex.

The concept here is the atrial (Bainbridge) reflex: when more blood returns to the heart, the walls of the right atrium stretch and trigger a reflex that increases heart rate. This response helps match the heart’s pumping to the greater venous return so cardiac output keeps up with the incoming blood.

How it works: stretch receptors in the right atrium detect increased filling. Afferent signals travel to the medulla, activating pathways that raise heart rate by boosting sympathetic drive to the SA node and reducing parasympathetic tone. The net result is a faster heart rate to move the additional venous return onward through the circulation.

The best description names the reflex itself as the mechanism behind the increase in heart rate with increased venous return. It’s not about a decrease in rate or no effect—the reflex specifically produces the rate rise in response to higher venous return, distinguishing it from other reflexes like the arterial baroreflex.

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