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Normal blood vessel (left) vs. vasodilation (right) 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]
This results suggests that this peripheral test reflects the physiology of the coronary endothelium. Since NO maintains low tone and high compliance of the small arteries at rest, [ 22 ] a reduction of age-dependent small artery compliance is a marker for endothelial dysfunction that is associated with both functional and structural changes in ...
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]
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.
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.
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
First, metabolites that are produced by active muscle use can alter skeletal muscle tone. Second, skeletal muscle can undergo hyperemia, which is a mechanism of local blood flow regulation with two major subtypes. Regardless of the subtype, the result of hyperemia is an increase in blood flow to the affected skeletal muscle. [4]
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.