Conversely, a decrease in ABP would lead to a decrease in the frequency of the action potentials.
The impulses from the baroreceptors in the aortic arch travel along the X cranial nerve (Vagus nerve) into the vasomotor control centre in the medulla oblongata at the base of the brain. The impulses from the baroreceptors in the carotid sinuses travel along the Henning's nerve and the IX cranial nerve (Glossopharyngeal nerve) into the medulla oblongata. A reduction in the number of impulses reaching the vasomotor control centre from the baroreceptors leads to vasoconstriction of the arterioles, which causes an increase in peripheral resistance. Heart rate is also increased, as well as the power of contraction of the heart (stroke volume); these two factors increase cardiac output. Overall, ABP is increased, which would reduce the number of impulses from the baroreceptors to the vasomotor control centres, and inhibit any further vasoconstriction of arterioles, increase in heart rate or stroke volume when ABP returns to a normal level.
Some people who suffer from a particular type of tachycardia called paroxysmal superventricular tachycardia; sometimes have to receive a massage of the carotid sinus area to stimulate the baroreceptors to decrease the heart rate.
Capillary Fluid Shift.
Capillary fluid shift can regulate blood pressure by changing the volume of blood circulating around the body. It does this by increasing or decreasing the volume of fluid moving from the capillaries into the interstitial space. This is regulated by a number of different pressures referred to as Starling forces'. The overall resultant force of these pressures, the effective filtration pressure (Peff), dictates whether the fluid moves out of the capillary into the interstitial fluid through filtration, or whether the fluid moves from the interstitial fluid into the capillary through reabsorbtion. The formula for this is give as:.
