Baroreceptor Reflex Mechanism

Baroreceptor Reflex Mechanism

1. Baroreceptor Reflex Ph. Ahmed Abd El-Moniem

2. Introduction Baroreceptors are a type of mechanoreceptors allowing for relaying information derived from blood pressure within the autonomic nervous system. Information is then passed in rapid sequence to alter the total peripheral resistance and cardiac output, maintaining blood pressure within a preset, normalized range.

3. Sympathetic activation leads to an elevation of total peripheral resistance and cardiac output via increased contractility of the heart, heart rate, and arterial vasoconstriction, which tends to increase blood pressure.

4. Conversely, parasympathetic activation leads to decreased cardiac output via decrease in heart rate, resulting in a tendency to lower blood pressure. By coupling sympathetic inhibition and parasympathetic activation, the baroreflex maximizes blood pressure reduction.

5. Baroreceptor exerts control of mean arterial pressure as a negative feedback loop. Nerve impulses from arterial baroreceptors are tonically active; increases in arterial blood pressure will result in an increased rate of impulse firing. Increased stimulation of the nucleus tractus solitarius by arterial baroreceptors results in increased inhibition of the tonically active sympathetic outflow to peripheral vasculature, resulting in vasodilation and decreased peripheral vascular resistance. The opposite is true of decreases in mean arterial pressure, resulting in decreased nerve firing and reduced stimulation of the nucleus tractus solitarius.

6. Under Supervision: Dr. Magdy Awny Ahmed Abd El-Moniem ID: 17037 Presented by: