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Vasodilation, also known as vasorelaxation, is the widening of blood vessels. [ 1 ] It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. [ 2 ] Blood vessel walls are composed of endothelial tissue and a basal membrane lining the lumen of the vessel ...
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in controlling hemorrhage and reducing acute blood loss.
Flow-mediated dilation (FMD) refers to dilation (widening) of an artery when blood flow increases in that artery. [1] [2] The primary cause of FMD is release of nitric oxide by endothelial cells. [1] To determine FMD, brachial artery dilation following a transient period of forearm ischemia is measured using ultrasound. [3]
Differences in vascular permeability between normal tissue and a tumor. Vascular permeability, often in the form of capillary permeability or microvascular permeability, characterizes the capacity of a blood vessel wall to allow for the flow of small molecules (drugs, nutrients, water, ions) or even whole cells (lymphocytes on their way to the site of inflammation) in and out of the vessel.
Blood vessels are the structures of the circulatory system that transport blood throughout the human body. [1] These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away from the tissues. Blood vessels are needed to sustain life, because all of the body's tissues rely on ...
Capillary comes from the Latin word capillaris, meaning "of or resembling hair", with use in English beginning in the mid-17th century. [4] The meaning stems from the tiny, hairlike diameter of a capillary. [4] While capillary is usually used as a noun, the word also is used as an adjective, as in "capillary action", in which a liquid flows ...
Vasospasm refers to a condition in which an arterial spasm leads to vasoconstriction. This can lead to tissue ischemia (insufficient blood flow) and tissue death (necrosis). Cerebral vasospasm may arise in the context of subarachnoid hemorrhage. Symptomatic vasospasm or delayed cerebral ischemia is a major contributor to post-operative stroke ...
Myogenic mechanism. The myogenic mechanism is how arteries and arterioles react to an increase or decrease of blood pressure to keep the blood flow constant within the blood vessel. Myogenic response refers to a contraction initiated by the myocyte itself instead of an outside occurrence or stimulus such as nerve innervation.