Our arteries have a basal myogenic tone, a basal constriction (vasoconstriction) mediated by smooth muscle cells of the artery wall.
This is regulated by calcium influx; calcium binds to contractile units/springs (sarcomeres) and makes them contract by a sliding mechanism
Vasoconstriction - On the myogenic response of small arteries (arterioles)
As increased blood flow and therefore increased blood pressure distends (passively) the arterioles, they respond by constriction to prevent damage of irrigated organs
The Bayliss myogenic response (1902).
A discovery on its regulation
Cell Reports 14, 1–9. March 8, 2016. http://dx.doi.org/10.1016/j.celrep.2016.02.019
by Blausen.com staff. "Blausen gallery 2014"
Increased blood flow >
Increased pressure by blood > [Equals to : Increased risk to damage irrigated organs]
Increased distention of cells of the artery >
Distended surface of smooth muscle cells of the artery >
Filamin A transmits pressure signal to calcium channels >
Channels open >
Calcium enters the cell >
Calcium binds to contractile units/springs (sarcomeres) and makes them slide on each other in a contraction movement >
Muscle cell contraction >
Reduction of artery diameter >
Reduction of blood flow >
Protection of irrigated organs