What is the function of the metarteriole in a capillary bed?

The metarterioles can serve either as thoroughfare channels to the venules, which bypass the capillary bed, or as conduits to supply the capillary bed. There are often cross-connections between the arterioles and venules as well as in the capillary network.

How do arterioles and metarterioles differ?

A metarteriole is a type of vessel that has structural characteristics of both an arteriole and a capillary. Slightly larger than the typical capillary, the smooth muscle of the tunica media of the metarteriole is not continuous but forms rings of smooth muscle (sphincters) prior to the entrance to the capillaries.

What’s the difference between true capillaries and metarteriole thoroughfare channels?

The thoroughfare channel, the tail end of the metarteriole that connects to the venule, lacks smooth muscle. True capillaries form the bulk of the capillary bed. They branch away from a metarteriole at its arteriole end and return to merge with the metarteriole at its venule end (thoroughfare channel).

What is the joining of a metarteriole and a thoroughfare channel called?

Figure 5. In a capillary bed, arterioles give rise to metarterioles. Precapillary sphincters located at the junction of a metarteriole with a capillary regulate blood flow. A thoroughfare channel connects the metarteriole to a venule.

Where are Metarterioles located?

Metarterioles exist in the mesenteric microcirculation, and the name was originally conceived only to define the “thoroughfare channels ” between arterioles and venules. In recent times the term has often been used instead to describe the smallest arterioles directly prior to the capillaries.

What are the branches of the metarteriole?

Metarterioles and Capillary Beds Each metarteriole arises from a terminal arteriole and branches to supply blood to a capillary bed that may consist of 10–100 capillaries depending on the metabolic needs of the surrounding tissues.

What are the 5 types of blood vessels?

There are five classes of blood vessels: arteries and arterioles (the arterial system), veins and venules (the venous system), and capillaries (the smallest bloods vessels, linking arterioles and venules through networks within organs and tissues) (Fig 1).

What are pericytes made of?

Pericytes (previously known as Rouget cells) are multi-functional mural cells of the microcirculation that wrap around the endothelial cells that line the capillaries throughout the body.

Where are pericytes derived from?

Abstract. Pericytes are believed to originate from either mesenchymal or neural crest cells. It has recently been reported that pericytes play important roles in the central nervous system (CNS) by regulating blood-brain barrier homeostasis and blood flow at the capillary level.