<prompt> Blood flow to brain is not influenced byPaC02P02Cerebral circulationSystemic circulation  <response>: Carotid and aoic bodies have very high rates of blood flow. These receptors are primarily activated by a reduction in paial pressure of oxygen PaO2, but they also respond to an increase in the paial pressure of carbon dioxide PaCO2 That is chemo receptors regulating blood flow to brain are insensitive to PaO2 despite the fact that it controls O2 content Ref: Ganongs Review of Medical Physiology Twenty-Third Edition Page No: 562 