Final answer:
The baroreceptor reflex responds to decreased mean arterial pressure by reducing baroreceptor firing rates, prompting the cardiovascular center to increase sympathetic stimulation to the heart and peripheral vessels, leading to elevated blood pressure.
Step-by-step explanation:
The baroreceptor reflex is a biological mechanism for maintaining vascular homeostasis, particularly in response to changes in blood pressure. When there is a decreased mean arterial pressure, the baroreceptors, which are specialized stretch receptors, detect this change and respond by reducing their rate of firing. This reduced firing rate is detected by the cardiovascular center in the medulla oblongata, which initiates a series of responses to restore normal blood pressure.
The flow of the baroreceptor reflex can be outlined as follows: decreased blood pressure leads to a reduced stretch of baroreceptors, resulting in a lower rate of action potentials being sent to the cardiovascular center. As a consequence, the center increases sympathetic stimulation and reduces parasympathetic stimulation, resulting in an increase in heart rate and force of contraction (via sympathetic stimulation) and vasoconstriction (narrowing) of peripheral vessels. These actions work together to raise blood pressure back towards normal levels.
Thus, the baroreceptor reflex helps to maintain blood pressure through a dynamic balance achieved by altering heart rate, strength of cardiac contraction, and vessel diameter.