Clinical Aspects of Cerebral Perfusion and ICP Flashcards
what percentage is cerebral blood flow of cardiac output?
15%
what is the most significant factor that determines cerebral blood flow at any given time?
cerebral perfusion pressure
what is cerebral perfusion pressure?
effective blood pressure gradient across the brain
increased ICP causes the cerebral perfusion pressure to ….
decrease
what are the factors that regulate cerebral blood flow under physiological conditions
CPP concentration of arterial CO2 arterial PO2
what is cerebral auto regulation?
the ability to maintain constant blood flow to the brain over a wide range of CPP
what happens to the arterioles when CPP is low?
arterioles dilate to allow adequate flow at decreased pressure
what happens to arterioles when CPP is high
the cerebral arterioles constrict
can cerebral blood flow always be auto regulated?
no, when CPP exceeds 150mm hg, hypertension, the system fails
what is a prominant cause of subacute to chronic intracranial hypertension?
Cerebral edema
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a barrier composed of astrocytic foot process wrapping around a capillary endothelium is composed of what?
tight junctions
can all substances that are carried in the blood reach the neural tissue?
no
what is the function sof endothelial tight junctions?
barrier to the passive movement of many substances in order to protect the sensitive neural tissue form toxic materials
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