Vasodilation: Difference between revisions

Latest revision as of 10:48, 15 February 2025

Vasodilation[edit]

Illustration of vasodilation in blood vessels

Vasodilation is the process by which blood vessels widen due to the relaxation of the muscular walls of the vessels. This physiological response is crucial for regulating blood flow and blood pressure in the body.

Mechanism[edit]

Vasodilation occurs when the smooth muscle cells within the walls of blood vessels, particularly the arteries and arterioles, relax. This relaxation is often triggered by various factors, including:

Nitric oxide: A potent vasodilator produced by endothelial cells.
Prostaglandins: Lipid compounds that have diverse hormone-like effects, including vasodilation.
Adenosine: A nucleoside that acts as a vasodilator in response to low oxygen levels.
Histamine: Released during allergic reactions, causing vasodilation and increased permeability of blood vessels.

Physiological Role[edit]

Vasodilation plays a critical role in:

Thermoregulation: By increasing blood flow to the skin, vasodilation helps dissipate heat and regulate body temperature.
Oxygen delivery: Enhancing blood flow to tissues increases the delivery of oxygen and nutrients.
Blood pressure regulation: Vasodilation decreases vascular resistance, which can lower blood pressure.

Clinical Significance[edit]

Vasodilation is a target for various pharmacological agents used to treat conditions such as:

Hypertension: Medications like ACE inhibitors and calcium channel blockers induce vasodilation to lower blood pressure.
Angina pectoris: Nitrates are used to dilate coronary arteries and improve blood flow to the heart muscle.
Erectile dysfunction: Drugs like sildenafil promote vasodilation in the penile arteries.

Related pages[edit]

@@ Line 1: / Line 1: @@
-'''Vasodilation''' is the widening of [[blood vessels]]. It results from relaxation of [[smooth muscle]] cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of [[vasoconstriction]], which is the narrowing of blood vessels.
+== Vasodilation ==
+[[File:Vasodilation.jpg|thumb|right|Illustration of vasodilation in blood vessels]]
+'''Vasodilation''' is the process by which blood vessels widen due to the relaxation of the muscular walls of the vessels. This physiological response is crucial for regulating blood flow and blood pressure in the body.
-When blood vessels dilate, the flow of blood is increased due to a decrease in vascular resistance. Therefore, dilation of arterial blood vessels (mainly the arterioles) decreases blood pressure. The response may be intrinsic (due to local processes in the surrounding tissue) or extrinsic (due to hormones or the nervous system). The response may also be either localized to a specific organ (depending on the metabolic needs of a particular tissue, as during strenuous exercise), or it may be systemic (seen throughout the entire systemic circulation).
+== Mechanism ==
+Vasodilation occurs when the smooth muscle cells within the walls of blood vessels, particularly the [[arteries]] and [[arterioles]], relax. This relaxation is often triggered by various factors, including:
-==Mechanisms==
+* '''[[Nitric oxide]]''': A potent vasodilator produced by endothelial cells.
-Endogenous substances and drugs that cause vasodilation are termed vasodilators. Such vasoactive substances may act directly on vascular smooth muscle (e.g., [[histamine]], [[bradykinin]], [[prostaglandins]], [[nitric oxide]]) or indirectly by altering the local environment of the vascular smooth muscle (e.g., [[hypoxia]], [[hypercapnia]], or metabolic acidosis) or by stimulating the release of other vasodilators (e.g., [[acetylcholine]], [[adenosine]]).
+* '''[[Prostaglandins]]''': Lipid compounds that have diverse hormone-like effects, including vasodilation.
+* '''[[Adenosine]]''': A nucleoside that acts as a vasodilator in response to low oxygen levels.
+* '''[[Histamine]]''': Released during allergic reactions, causing vasodilation and increased permeability of blood vessels.
-==Clinical significance==
+== Physiological Role ==
-Vasodilation directly affects the size of the blood vessels, and therefore the distribution of blood in the body. This has a direct effect on symptoms of certain diseases. For example, in [[angina pectoris]], vasodilators are used to open up the blood vessels in the heart, increasing blood flow and decreasing the symptom of chest pain.
+Vasodilation plays a critical role in:
-==See also==
+* '''[[Thermoregulation]]''': By increasing blood flow to the skin, vasodilation helps dissipate heat and regulate body temperature.
+* '''[[Oxygen delivery]]''': Enhancing blood flow to tissues increases the delivery of oxygen and nutrients.
+* '''[[Blood pressure regulation]]''': Vasodilation decreases vascular resistance, which can lower blood pressure.
+== Clinical Significance ==
+Vasodilation is a target for various pharmacological agents used to treat conditions such as:
+* '''[[Hypertension]]''': Medications like [[ACE inhibitors]] and [[calcium channel blockers]] induce vasodilation to lower blood pressure.
+* '''[[Angina pectoris]]''': [[Nitrates]] are used to dilate coronary arteries and improve blood flow to the heart muscle.
+* '''[[Erectile dysfunction]]''': Drugs like [[sildenafil]] promote vasodilation in the penile arteries.
+== Related pages ==
 * [[Vasoconstriction]]
-* [[Blood vessel]]
+* [[Blood pressure]]
-* [[Smooth muscle]]
+* [[Endothelium]]
+* [[Cardiovascular system]]
 [[Category:Cardiovascular physiology]]
-[[Category:Human homeostasis]]
-[[Category:Medical terminology]]
-{{stub}}