2023-04-27 16:55:05
The vasoconstriction means the natural process ofdecrease in the caliber of blood vessels due to the contraction of muscle fibers. With the vasodilatationthis phenomenon contributes to the vasomotion.
Vasoconstriction mainly affects medium and especially small caliber arterial vessels (arterioles). It occurs under the command of nerve impulses (vasomotor nerve centers) depending on the amount of oxygen and bicarbonate in the blood and the expression of certain hormones.
Vasoconstriction occurs in the event of muscle damage, stress, pain, certain physiological conditions (such as cold), exposure to certain vasoconstrictor agents (such as nicotine) or even certain pathologies (such as arterial hypertension).
Vasoconstriction and arterial pressure: what is the link?
Vasomotricity ensures the internal balance of the body on a continuous basis. In the regulation of blood pressure, vasoconstriction helps to raise a pressure that is too low, while vasodilation reduces excess pressure.
Vasoconstriction, a process of nervous and hormonal origin
Vasodilation is triggered by nerve impulse control but also by the release of certain hormones (angiotensin II, adrenaline, norepinephrine, serotonin, antidiuretic hormones and endothelins…). Vasoconstriction thus leads to a decrease in blood flow in the organ in question. The surfaces of the vessel will then stick together becoming adhesive.
Triggers: what causes vasodilation?
Factors likely to trigger vasoconstriction are:
- The consumption of caffeine by its stimulating action on the central nervous system.
- The consumption of tobacco. The nicotine results in reversible arterial vasoconstriction a few hours following smoking. However, this phenomenon becomes chronic in heavy smokers.
- The stress : the latter causes a surge of adrenaline causing the constriction of blood vessels.
- The cold : under the effect of the latter, the peripheral circulation can be reduced by the vasoconstriction of the vessels which results in the closure of the cutaneous capillary loops and the maintenance of heat in the central and vital parts of the body. This is what we more commonly call “goosebumps” or “horripilation”.
- Some diseases (Raynaud’s syndrome, high blood pressure…) ;
- The taking of some toxicof narcotics (as the cannabis) or some medications (nasal vasoconstrictors, medications to stop bleeding…).
Vasoconstriction: a sometimes pathological phenomenon
Vasoconstriction can occur in several pathologies. Here are some examples:
- The reversible cerebral vasoconstriction syndrome (SVCR) is attributed to a transient and reversible abnormality in the regulation of cerebral arterial tone, which results in multifocal and diffuse vasoconstriction and vasodilation. It mainly affects women following 45 years. The main sign is the occurrence of thunderclap headaches triggered by sexual activity or a Valsalva maneuver. Most cases are secondary to taking vasoactive substances (cannabis, SSRI antidepressants, nasal decongestants) and/or postpartum.
- The hypoxic pulmonary vasoconstriction (HPV) is a reflex mechanism unique to the pulmonary circulation. Unlike all other tissues, the drop in partial oxygen pressure will induce local vasoconstriction, reducing blood flow in the poorly ventilated area. This phenomenon can occur with altitude hypoxia and focal lung lesions.
- L’high blood pressure which may involve phenomena of arterial vasoconstriction. This can have consequences on certain organs such as the brain with a risk ofCVA (cerebrovascular accident).
- The Raynaud’s syndrome which is manifested by excessive vasoconstriction of the small vessels of the extremities of the body (hands, feet), particularly during cold weather or stress.
- Migraine with aura which would be due to a contraction followed by a sudden dilation of the vessels located in the meninges.
What are the symptoms of vasoconstriction?
Vasoconstriction can be accompanied by certain symptoms depending on its cause:
- a pain ;
- a loss of blood supply ;
- and stop bleeding ;
- a high blood pressure ;
- a increased heart rate ortachycardia.
Vasoconstriction: what to do to stop it?
Most of the time, vasoconstriction ceases spontaneously when the cause of its triggering has disappeared. It is therefore advisable to warm up in case of cold, to stop smoking, to stop taking medication or to wait for a wound to stop bleeding so that the phenomenon of constriction dissipates.
When vasoconstriction is involved in a particular pathological condition (arterial hypertension, stroke, Raynaud’s syndrome, etc.), specific management (sometimes urgently) is necessary.
1682632175
#Vasoconstriction #understanding #contraction #blood #vessels
