Search results
Results from the WOW.Com Content Network
If vasodilatory shock being left untreated, even brief hypotensive periods can result in myocardial and renal injury. [21] [35] It can also increased mortality in the critically ill. [21] Refractory shock has an all-cause mortality rate greater than 50% within a month [1] [dubious – discuss].
Vasodilation occurs as part of the process of inflammation, which is caused by several factors including presence of a pathogen, injury to tissues or blood vessels, and immune complexes. [7] In severe cases, inflammation can lead to sepsis or distributive shock. [11] Vasodilation is also a major component of anaphylaxis. [12]
Injuries to nerves of the lower trunk of the brachial plexus (Klumpke's paralysis) and compression of median nerve at the flexor retinaculum of the hand (Carpal Tunnel Syndrome) can cause vasomotor changes at the areas innervated by the nerves. This area of the skin will become warmer because of vasodilation (loss of vasoconstriction). [5]
These endothelial products include nitric oxide and endothelin-1 that are released in response to either chemical stimuli, like histamine, or increased shear stress on the blood vessel (meaning the amount of stress exerted by blood on the blood vessel walls). While nitric oxide causes vasodilation, endothelin-1 causes vasoconstriction.
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.
When cardiac output goes down, catecholamines like epinephrine and norepinephrine, ADH, and angiotensin II are released, all of which cause vasoconstriction of blood vessels which increases of vascular resistance, and increased heart rate, which, increases cardiac output, and these combined effects increase blood pressure.
Agonists of alpha-2 receptors in the vascular smooth muscle lead to vasoconstriction. However, in clinical practice drugs applied intravenously that are agonists of alpha-2 receptors such as clonidine lead to powerful vasodilation, which causes a decrease in blood pressure by presynaptic activation of the receptors in the sympathetic ganglia ...
Norepinephrine causes predominately vasoconstriction with a mild increase in heart rate, whereas epinephrine predominately causes an increase in heart rate with a small effect on the vascular tone; the combined effect results in an increase in blood pressure.