Blood Pressure Regulation

In humans, blood pressure is tightly monitored and controlled. Maintained stable pressure is the product of regulating many cardiovascular parameters cohesively, and as such, it serves as a useful marker of overall cardiovascular health.

Rapid homeostatic control.

Calculating the product of blood pumped out of the heart, and the resistance met by blood force through various blood vessels gives arterial blood pressure:

Arterial blood pressure = cardiac output x total peripheral resistancearterial blood pressure equals cardiac output times the total peripheral resistance

Tension-sensing baroreceptors in the aortic arch and carotid sinus detect any slight changes as a measure of receptor stretch. Counteractive responses work quickly to maintain homeostatic balance.

Responding to change

Increased baroreceptor stretching detects increased arterial pressure and increases the rate of action potential firing to the brain's cardiovascular center. The high signal rate triggers an autonomic parasympathetic neural reflex. The resulting vasodilation compensates for increased cardiac output and stroke volume to maintain homeostatic control. Inversely, decreased baroreceptor stretching detects a drop in arterial blood pressure. An autonomic sympathetic reflex is triggered, resulting in vasoconstriction to increase blood pressure back to normal range.

Other control methods

Sympathetic and parasympathetic stimulation also influences heart rate and stroke volume. Exercise, blood carbon dioxide level, and pH and also trigger stimulatory and inhibitory signals that exert control. The summation of all this information is what allows the cardiovascular system to cope with the physical challenges life throws at us.