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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, concentric smooth muscle layers on top of endothelial tissue, and an adventitia over ...
To summarize, vasoconstriction is a physiological process that involves the narrowing of blood vessels, particularly arteries and arterioles, resulting in a reduction of blood flow to specific tissues or organs. This phenomenon is primarily regulated by the contraction of smooth muscle cells within the vessel walls.
Atherosclerosis [a] is a pattern of the disease arteriosclerosis, [8] characterized by development of abnormalities called lesions in walls of arteries.This is a chronic inflammatory disease involving many different cell types and is driven by elevated levels of cholesterol in the blood. [9]
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]
An arteriole is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries. [1]Arterioles have muscular walls (usually only one to two layers of smooth muscle cells) and are the primary site of vascular resistance.
When blood pressure is increased in the blood vessels and the blood vessels distend, they react with a constriction; this is the Bayliss effect. Stretch of the muscle membrane opens a stretch-activated ion channel. The cells then become depolarized and this results in a Ca 2+ signal and triggers muscle contraction. No action potential is ...
"Onion-skin" renal arteriole. This is a type of arteriolosclerosis involving a narrowed lumen. [4] The term "onion-skin" is sometimes used to describe this form of blood vessel [14] with thickened concentric smooth muscle cell layer and thickened, duplicated basement membrane.
Functional hyperaemia is an increase in blood flow to a tissue due to the presence of metabolites and a change in general conditions. When a tissue increases its activity, there is a well-characterized fall in the partial pressure of oxygen and pH, along with an increase in partial pressure of carbon dioxide, and a rise in temperature and the concentration of potassium ions.