Maintenance and Regulation of Peripheral Circulation
Pressure receptors (baroreceptors) located in the wall of the internal carotid arteries and in the arch of aorta, when stimulated by a rapid loss of pressure due to sudden volume loss (e.g., Haem0rrhage)accelerate the heart rate and cause peripheral vasoconstriction.
Chemical receptors present in the aortic and carotid bodies get stimulated by change in blood gas levels (i.e., 0, and CO,). Acute changes will activate the adrenergic system, increase peripheral vasoconstriction and heart rate further.
With long-term volume depletion, the renal mechanism is activated causing retention of sodium and water and this in turn increase arterial pressure and circulating blood volume.