MadSci Network: General Biology |
The Bainbridge Reflex is one of the ways by which the heart keeps blood flowing properly. It is important that the amount of arterial blood being pumped out of the heart to the body equals the amount of venous returning to the heart from the body. When this does not happen -- when, for example, the left side of the heart fails because of heart disease -- the arterial output drops and blood backs up in the lungs and on the venous side of the heart. The first chamber of the heart which returning venous blood enters is the right atrium. If the inflow of venous blood increases, it will enter and distend the right atrium more. Stretch receptors in the wall of the right atrium detect this increased stretching and send signals reporting this to the brain. The brain sends instructions back to the heart causing the heart rate to increase. This increases the output of the heart and decreases the amount of blood in the right atrium. This increase in right atrial stretching (that is, increased venous return) leading to increased heart rate (that is, increased arterial output) is called the Bainbridge Reflex.
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