Biological Systems MCAT Practice Exam

What is monitored by baroreceptors in relation to cardiac function?

1. Heart rate

2. Blood pressure

3. Stroke volume

4. Cardiac output

The correct answer is: Blood pressure

Baroreceptors are specialized mechanoreceptors that play a crucial role in the regulation of blood pressure within the cardiovascular system. They are primarily located in the walls of the carotid arteries and the aortic arch, where they can detect changes in the stretch of the arterial walls that occur with fluctuations in blood pressure. When blood pressure increases, baroreceptors become more stretched and send increased afferent signals to the central nervous system. In response, the body initiates compensatory mechanisms to lower blood pressure, such as decreasing heart rate and dilating blood vessels. Conversely, when blood pressure decreases, baroreceptors send fewer signals to the brain, allowing for the activation of mechanisms that raise blood pressure, including increasing heart rate and constricting blood vessels. While heart rate, stroke volume, and cardiac output are important parameters of cardiac function, the primary role of baroreceptors is to monitor and respond to changes in blood pressure. This monitoring helps maintain homeostasis and ensures that blood flow to vital organs remains steady despite fluctuations in bodily conditions or posture.