Glomus body

A glomus body (or glomus apparatus) is a component of the dermis layer of the skin, involved in body temperature regulation. The glomus body consists of an arteriovenous shunt surrounded by a capsule of connective tissue. Glomus bodies are most numerous in the fingers and toes. The role of the glomus body is to shunt blood away from the skin surface when exposed to cold temperature, thus preventing heat loss, and allowing maximum heat flow to the skin in warm weather to allow heat to dissipate. The glomus body has high sympathetic tone and potentiation leads to near complete vasoconstriction.

Endothelial cells form a single, continuous layer that lines all vascular segments. Junctional complexes keep the endothelial cells together in arteries but are less numerous in veins. The organization of the endothelial cell layer in capillaries varies greatly, depending on the organ. The glomus bodies in the skin and elsewhere are unusual in that their “endothelial cells” exist in multiple layers of cells called myoepithelioid cells. These glomus bodies control small arteriovenous shunts or anastomoses.

The arteriovenous shunt in a glomus body is called the segmentum arteriale anastomosis arteriovenosae glomeriformis or Sucquet-Hoyer anastomosis. It is one of the body's examples of a normal anatomic arteriovenous shunt (as opposed to an abnormal arteriovenous fistula). Metarterioles are another.

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