Bainbridge reflex

From Wikipedia, the free encyclopedia

The Bainbridge reflex is an increase in heart rate due to an increase in the blood pressure of the right atrium.

As venous return increases, the pressure in the superior and inferior vena cavae increase. This results in an increase in the pressure of the right atrium, which stimulates the atrial low pressure receptors. These receptors in turn signal to the medullary control centres the increased pressure, resulting in tachycardia.

Increasing the heart rate serves to decrease the pressure in the superior and inferior vena cavae by drawing more blood out of the right atrium. This results in a decrease in atrial pressure, which serves to bring in more blood from the vena cavae, resulting in a decrease in the venous pressure of the great veins. This continues until right atrial blood pressure returns to normal levels, upon which the heart rate decreases to its original level.

---