Search results
Results from the WOW.Com Content Network
Post-capillary venules are the smallest of the veins with a diameter of between 10 and 30 micrometres (μm). When the post-capillary venules increase in diameter to 50μm they can incorporate smooth muscle and are known as muscular venules. [1] Veins contain approximately 70% of total blood volume, while about 25% is contained in the venules. [2]
High endothelial venules (HEV) are specialized post-capillary venules characterized by plump endothelial cells as opposed to the usual flatter endothelial cells found in regular venules. [1] HEVs enable lymphocytes circulating in the blood to directly enter a lymph node (by crossing through the HEV).
Terminations of the vasa recta form the straight venules, branches from the plexuses at the apices of the medullary pyramids. They run outward in a straight course between the tubes of the medullary substance and join the interlobular veins to form venous arcades. These in turn unite and form veins which pass along the sides of the renal pyramids.
The venous system apart from the post-capillary venules is a high volume, low pressure system. Vascular smooth muscle cells control the size of the vein lumens, and thereby help to regulate blood pressure. [31] The post-capillary venules are exchange vessels whose ultra-thin walls allow the ready diffusion of molecules from the capillaries. [10]
The second sector is the capillary sector, which is represented by the capillaries, where substance and gas exchange between blood and interstitial fluid takes place. Finally, the post-capillary sector is represented by the post-capillary venules, which are formed by a layer of endothelial cells that allow free movement of some substances. [3]
Venules; Veins. Large collecting vessels, such as the subclavian vein, the jugular vein, the renal vein and the iliac vein. Venae cavae (the two largest veins, carry blood into the heart). Sinusoids. Extremely small vessels located within bone marrow, the spleen and the liver.
A capillary is a small blood vessel, from 5 to 10 micrometres in diameter, and is part of the microcirculation system. Capillaries are microvessels and the smallest blood vessels in the body.
Gap cell junction created between two neighboring cells by connexin. In the central nervous system (CNS), pericytes wrap around the endothelial cells that line the inside of the capillary.