Chapter 19.1, Problem 21SR

Summary Introduction

To describe: The function of precapillary sphincters and the role it plays during exercise and cold temperatures.

Introduction: The band of smooth muscle fibers that encircles at the entrance to each capillary at the point where each capillary originates is called precapillary sphincters. These sphincters are involved in adjusting the flow of blood into the capillaries. This is carried out by the contraction and relaxation of smooth muscle cells present in the precapillary sphincters.