How the brain regulates its blood flow andwhat chemical stimulus is the most potent inactivating its regulatory mechanisms
How the brain regulates its blood flow and
what chemical stimulus is the most potent in
activating its regulatory mechanisms
cerebral blood flow regulation is essential for normal brain function . It is largely independent of perfusion pressure when autoregulation is intact . Cerebral circulation is regulated mainly by changes of vascular resistance . Resistance can be modulated by local chemical and endothelial factors , by autacoids , and by release of transmitters from perivascular nerves .
There is a unique mechanism for cerebral blood flow control known as neurovascular coupling . This mechanism ensures a rapid increase in the rate of cerebral blood flow and oxygen delivery to activated brain structures . The neurovascular unit is composed of astrocytes , mural vascular smooth muscle cells and pericytes and endothelia and regulates neurovascular coupling
Cerebral arteries are innervated by several systems . The sympathetic noradrenergic fibres originate from the superior cervical ganglion . By releasing the constricting transmitters norepinephrine and neuropeptide Y this system extends the range of autoregulation .
In short it is said that the regulation of cerebral circulation involves the same mechanisms as in peripheral organs .
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