NEET PG DENTAL EXAM

Detailed explanation-1: -The precapillary sphincter has now also been found in the brain, where it regulates blood flow to the capillary bed. The sphincter can open and close the entrance to the capillary, by which contraction causes blood flow in a capillary to change as vasomotion occurs.

Detailed explanation-2: -Precapillary sphincters represent important anatomical sites of blood flow regulation due to their strategic placement at branch points of proximal PAs, where they reduce both pressure and RBC flux into the downstream capillary bed and thereby regulate perfusion along the PA (Fig. 7).

Detailed explanation-3: -Chemical signals work at the level of the precapillary sphincters to trigger either constriction or relaxation. As you know, opening a precapillary sphincter allows blood to flow into that particular capillary, whereas constricting a precapillary sphincter temporarily shuts off blood flow to that region.