Precapillary resistance is the modulation of blood flow by capillaries through

vasomotion Vasomotion is the spontaneous oscillation in tone of blood vessel walls, independent of heart beat, innervation or respiration. While vasomotion was first observed by Thomas Wharton Jones in 1852, the complete mechanisms responsible for its genera ...

, either opening ( dilating) and letting blood pass through, or by constricting their lumens, reducing bloodflow through the capillary bed (occluding the passage of blood). It is not entirely clear how precapillary resistance is created in many parts of the body.

Precapillary sphincter A precapillary sphincter is a band of contractile mural cells either classified as smooth muscle or pericytes that adjusts blood flow into capillaries. They were originally described in the mesenteric microcirculation, and were thought to only res ...

s are

smooth muscle Smooth muscle is an involuntary non-striated muscle, so-called because it has no sarcomeres and therefore no striations (''bands'' or ''stripes''). It is divided into two subgroups, single-unit and multiunit smooth muscle. Within single-unit mus ...

structures that mediate the precapillary resistance in the

mesenteric The mesentery is an organ that attaches the intestines to the posterior abdominal wall in humans and is formed by the double fold of peritoneum. It helps in storing fat and allowing blood vessels, lymphatics, and nerves to supply the intestines ...

microcirculation.

References

Angiology Circulatory system {{Arteries and veins

See also

References