Vasoconstriction is a phenomenon where blood vessels contract. Basically, it happens in all of us and usually does not lead to any negative consequences, and is even beneficial: vasoconstriction allows you to regulate blood pressure, and - in the case of any damage to a blood vessel - it limits blood loss from it. Sometimes, however, vasoconstriction can even be very harmful - what situations are we talking about?

Vasoconstrictionor vasoconstriction is one of the processes that help maintain homeostasis in the body. It is important primarily for maintaining the proper functioning of the circulatory system - it allows you to regulate blood pressure and can prevent excessive heat loss from the body or lead to directing blood to those organs that have the greatest need for it.

It is a completely natural and expected phenomenon, but sometimes vasoconstriction does not help at all, and in fact it only harms. But how does it even happen?

Vasoconstriction: mechanism

Various types of cells are located in the walls of blood vessels, incl. smooth muscle cells. Vasoconstriction may occur when muscle cells contract - this phenomenon occurs due to the increased concentration of calcium ions inside these cells. When the muscle cells contract, then the entire lumen of the blood vessel narrows - blood flow within such a structure decreases, but in such a situation the blood pressure increases.

Vasoconstriction: triggers

Vasoconstriction generally does not happen by itself - the contraction that determines it is stimulated by various types of mediators. They can be, first of all, substances produced in the body, such as :

  • adrenalina
  • noradrenalina
  • dopamine
  • thromboxane
  • endothelin
  • angiotensin II
  • antidiuretic hormone (vasopressin)
  • thrombin

It is possible, however, that the vasoconstriction will occur as a result of influencing the organism by definitely different, exogenous substances. They can be, among others present in coffeecaffeine as well as various drugs (e.g. cocaine).

There are also many different pharmaceuticals that can lead to the constriction of blood vessels - here, examples include drugs used in the treatment of rhinitis (such as oxymetazoline), vasopressin analogues or triptans used in migraine patients .

Vasoconstriction: when does it happen?

Vasoconstriction is most often a phenomenon beneficial for the body. It happens, for example, when the human body is exposed to low temperature - in this case, the contraction of blood vessels located in the skin allows to reduce heat loss from the body.

There are also situations where vasoconstriction enables the provision of blood supply to those organs that need it most - this is the case, for example, in the case of blood loss, where the vessels supplying e.g. digestive tract so that the blood supply, e.g. to the central nervous system, is not reduced.

Generally, vasoconstriction is a phenomenon of very great importance - even thanks to it and the process opposite to it, which is vasodilation, it is possible to maintain appropriate blood pressure values ​​in the body. Not always, however, vasoconstriction is a beneficial phenomenon - it sometimes results in very serious complications.

Vasoconstriction: negative consequences

There are several different pathological processes in which vasoconstriction occurs. It has been suggested that excessive vasoconstriction may be associated with headaches. However, this issue is quite interesting because, on the other hand, in the course of one of these types of problems - migraines - the opposite abnormality occurs, which is excessive vasodilation (some of the medications used in migraine headaches also result in the constriction of blood vessels). ).

Another problem that is related to vasoconstriction is Raynaud's phenomenon. It is the occurrence of paroxysmal, sudden spasm of the arteries, usually in the hands or feet, and may occur when exposed to cold, when emotional, or for no apparent reason. The ailment can be idiopathic, as well as being one of the symptoms of many different diseases, such as:

  • systemic scleroderma
  • systemic lupus erythematosus
  • rheumatoid arthritis

Most common symptomRaynaud's - fortunately - does not result in any long-term complications, but it is possible that if treatment is completely abandoned, the problem will lead to permanent bodily injuries (e.g., necrosis of the fingertips).

Vasoconstriction also occurs in the course of shock. This type of problem can be caused by various abnormalities - significant blood loss as well as severe dehydration or an allergic reaction can lead to shock. In this case, the constriction of blood vessels in a situation where the volume of circulating blood is reduced, is primarily aimed at securing the supply of blood to the most important organs, such as e.g. heart or brain.

One of the more serious problems in which vasoconstriction can also occur is subarachnoid hemorrhage. In this case, vasoconstriction may take place several days after the onset of hemorrhage and it is dangerous primarily because its occurrence may lead to a reduction in the supply of oxygen and nutrients to nerve cells, which may intensify the damage caused by the hemorrhage itself. only subarachnoid hemorrhage.

About the authorBow. Tomasz NęckiA graduate of medicine at the Medical University of Poznań. An admirer of the Polish sea (most willingly strolling along its shores with headphones in his ears), cats and books. In working with patients, he focuses on always listening to them and spending as much time as they need.

Category:

Cardiology