Knowra Venule Venule A small blood vessel that collects blood from capillaries and carries it toward larger veins. Its walls are thinner and less muscular than those of larger veins.
Capillary : A microscopic blood vessel where gases, nutrients, and wastes move between blood and tissues. Capillaries drain directly into venules after exchange with surrounding tissues.
Microcirculation : Blood flow through the smallest vessels, including arterioles, capillaries, and venules. Venules are the outflow segment of this tissue-level circulation.
Inflammation : A tissue response to injury or infection involving immune cells, signaling molecules, and changes in blood flow. Inflammatory signals alter venular adhesion and permeability, enabling immune-cell recruitment.
Artery : A blood vessel that carries blood away from the heart. Arteries carry blood outward under higher pressure; venules collect it after capillary exchange.
Postcapillary venule : The smallest venule, formed immediately downstream of capillaries and specialized for exchange and leukocyte migration. This first segment receives capillary blood and is a principal site of immune-cell exit.
Blood vessel : A tubular structure that transports blood through the body. A venule is a small vessel defined by its position in the vascular network.
Edema : Excess accumulation of fluid in the interstitial spaces or body cavities. Increased venular leakage can contribute to fluid accumulation in tissues.
Venous sinus : A blood-filled channel that drains blood without the usual structure of a vein wall. Venous sinuses are specialized drainage channels, unlike the small tubular venules.
Leukocyte extravasation : The movement of white blood cells from the bloodstream through vessel walls into tissues. Inflamed venules provide the main route for white blood cells to leave the circulation.
Arteriole : A small artery that delivers blood to capillary beds and helps regulate their flow. Arterioles lie upstream of the capillaries that drain into venules.
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