The blood vessels of human beings are designed to change their size accordingly to the surrounding environments. Those changes fall into two types: vasodilation and vasoconstriction.
What are vasodilation and vasoconstriction?
Vasodilation is the enlargement of blood vessels. It occurs when the muscles in the vessel walls relax. The opposite of vasodilation is vasoconstriction. It is a condition in which the blood vessels are narrowed down. In other words, a constricted vessel raises the blood pressure, while an enlarged one pulls the pressure down. These two conditions can either happen to a single organ in the whole body.
In order to survive the environment changes, warm-blooded animals develop vasodilation and vasoconstriction. There are certain temperature limits to which the body needs to set up. When the external temperature crosses that limit, the body will make adjustments to the blood vessels. The blood vessels closest to the body’s extremities will dilate, allowing warm blood to get close to the skin. When it is, the heat from the blood can get out of the body, and get absorbed by the external environment. The animal gets to keep its optimal temperature. The reverse mechanism will be used when the environment gets too cold. If outside temperature lowers, vasoconstriction occurs, creating the opposite effect by keeping the heat from warm blood inside for the most vital organs.
The constriction of blood vessels may significantly elevate the body’s temperature, causing vascular conflict. The result can be seen in paler skin since the blood supply has been reduced. Vasoconstriction usually happens to large arteries as a natural tactic to get the most effective result. However, in some people, it can affect small arterioles as well.
Causes of vasodilation and vasoconstriction
Since the body needs blood to operate continuously, vasodilation and vasoconstriction can start anytime at any part of the body. Causes of vasodilatation are vasodilators, including:
- Abnormal releases of the hormones,
- Neural signals,
- Certain medications, such as drugs prescribed for high blood pressure,
- Histamine and lactic acid,
- Physical activities,
- Changes in the living habitat.
Similarly, causes of vasoconstriction are vasoconstrictors, including:
- Excessive consumption of caffeine, Tobacco use,
- Alcohol consumption,
- Antihistamine drugs,
- Substance abuse,
Increased sodium and monosodium glutamate intake.
Even if a drug is responsible for causing vasodilation or vasoconstriction, maintaining the use of it might be necessary due to is beneficial effects to the patient’s health, especially those with a chronic disease like high blood pressure. It may be necessary to weigh the advantages against the side effect when considering a treatment plan.
Hello Health Group does not provide medical advice, diagnosis or treatment.
Review Date: December 17, 2016 | Last Modified: January 4, 2017
What is Vasodilatation? http://www.wisegeekhealth.com/what-is-vasodilatation.htm. Assessed October 15, 2016.
Vasoconstriction. http://diseasespictures.com/vasoconstriction/. Assessed October 15, 2016.