venule

Examples of venule in the following topics:

• Venules

  • Venules are small blood vessels in the microcirculation that connect capillary beds to veins.
  • Venules range from 8 to 100μm in diameter and are formed when capillaries come together.
  • Many venules unite to form a vein.
  • In contrast to regular venules, high-endothelial venules (HEV) are specialized post-capillary venous swellings.
  • Venules form when capillaries come together and converging venules form a vein.

• Arterioles

  • The microcirculation involves the flow of blood in the smallest blood vessels, including arterioles, capillaries, and venules.
  • Arterioles are part of the microcirculation system, along with capillaries, arteries, veins, venules, and tissue cells.

• Blood Flow in the Skin

  • The anastomoses connect cutaneous arterioles and venules directly, playing an important role in the reduction of blood flow in a cold environment.

• Blood Vessel Structure

  • Capillaries in turn merge into venules, then into larger veins responsible for returning the blood to the heart.
  • In smaller arterioles or venules, this subendothelial layer consists of a single layer of cells, but can be much thicker in larger vessels such as the aorta.

• Capillaries

  • Capillaries form a network through body tissues that connects arterioles and venules and facilitates the exchange of water, oxygen, carbon dioxide, and many other nutrients and waste substances between blood and surrounding tissues.
  • A capillary bed can consist of two types of vessels: true capillaries, which branch mainly from arterioles and provide exchange between cells and the circulation, and vascular shunts, short vessels that directly connect arterioles and venules at opposite ends of the bed, allowing for bypass.

• Biological and Medical Applications

  • The capillaries connect to venules, into which the deoxygenated blood passes from the cells back into the blood.
  • The micro-circulation (arterioles, capillaries and venules) constitutes most of the area of the vascular system and is the site of the transfer of O2 into the cells.

• Blood Flow Through the Body

  • If all of the sphincters are closed, then the blood will flow directly from the arteriole to the venule through the thoroughfare channel.
  • After the blood has passed through the capillary beds, it enters the venules, veins, and finally the two main venae cavae (singular, vena cava) that take blood back to the heart.

• Glomerular Diseases

  • Unlike most other capillary beds, the glomerulus drains into an efferent arteriole rather than a venule.

• Systemic and Pulmonary Circulation

  • The deoxygenated blood continues through the capillaries which merge into venules, then veins, and finally the venae cavae, which drain into the right atrium of the heart.

• Supply of Blood and Nerves to the Kidneys

  • The renal vein drains blood from venules that arise from the interlobular capillaries inside the parenchyma of the kidney.