Why does local blood flow autoregulation fail to maintain consistent perfusion pressure in a cerebral vessel experiencing subarachnoid hemorrhage?

💡 Explanation

Vasospasm overcomes metabolic control because subarachnoid hemorrhage releases vasoactive substances that induce intense vasoconstriction of cerebral vessels; therefore, autoregulation fails due to vascular smooth muscle hyper-reactivity, rather than a failure of metabolic signaling or myogenic response alone.

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