Vasomotoriske

Vasomotoriske refers to the regulation of blood vessel diameter and vascular tone, primarily controlled by the autonomic nervous system. In most languages, the vasomotor system governs how arterioles constrict or dilate to adjust blood flow and systemic vascular resistance, thereby influencing blood pressure. The central control for this regulation lies in the vasomotor center of the medulla oblongata, which modulates sympathetic outflow to the smooth muscle of blood vessels.

The mechanisms behind vasomotor control are multifaceted. Neural input from sympathetic nerves causes smooth muscle contraction, leading to vasoconstriction, while reduced sympathetic activity or local vasodilatory signals promote relaxation. Hormones such as norepinephrine, epinephrine, angiotensin II, and endothelin can augment constriction, whereas nitric oxide and other endothelium-derived factors promote dilation. Local metabolic factors, including carbon dioxide, hydrogen ions, oxygen tension, and temperature, also influence vascular tone to match tissue needs. The endothelium plays a key role by releasing relaxing or contracting substances in response to shear stress and other stimuli.

Clinically, vasomotor dysfunction can contribute to conditions such as hypertension, orthostatic hypotension, and vasospastic disorders like Raynaud phenomenon. Autonomic disorders, diabetes, and certain neuropathies may impair vasomotor regulation. Treatments in some cases target vascular tone with medications that modify sympathetic activity or smooth muscle responsiveness, reflecting the central importance of vasomotoriske in cardiovascular regulation.