Bayliss effect

The Bayliss effect or myogenic autoregulation is a named after the British physiologists William Bayliss contractile response of blood vessels in the local control of blood circulation ( autoregulation ) to maintain a constant perfusion of an organ or tissue.

Varies by an increase in blood pressure, the wall of a small artery or arteriole stretch, this is answered by a contraction of the vascular smooth muscle cells. Thus, the radius of the blood vessel and the vascular resistance decreases increases ( Hagen- Poiseuillesches Act). With a lessening of intravascular pressure ( from Latin intra = " within ", vas = " vessel " ), the vascular muscles goes back to its original ( " basal " ) tone. In this way, a constant blood flow to organs and tissues can be maintained even with strongly fluctuating blood pressure (in the range between about 120 and 200 mmHg).

The molecular basis for the Bayliss effect lies in the opening of mechanosensitive cation channels, which cause a calcium influx from the interstitial space ( extracellular space ) in the muscle cells. The calcium ions then form a complex with the protein, calmodulin; This complex activates myosin light - chain kinase (MLC -K) which passes through phosphorylation ( interconversion ) for activating the motor protein myosin II, enabling contraction of vascular smooth muscle cell.

This type of circulatory regulation is completely independent of the autonomic innervation of the blood vessels. This means that even with a transection of the vascular nerves supplying the Bayliss effect remains. Only with the use of a spasmolytic, such as papaverine, the effect of a relaxation of vascular smooth muscle cells can be lifted.

Bayliss effect, for example in the kidneys, in the gastrointestinal tract and in the brain detected, but not in the skin and in the lung.

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