- More sensitive to even short periods of reduced blood flow than other organs in the body
- Clinically a reduction in CBF to 30 ml/100g/min for as little as 5 seconds can result in syncope and loss of consciousness as occurs during a vasovagal episode
- Decreases in CBF lead to progressive cellular ischaemia:
Cerebral Blood Flow
Effect
<50 mL/100 g/min
Cellular acidosis
<40 mL/100 g/min
Impaired protein synthesis
<30 mL/100 g/min
Cellular oedema
<20 mL/100 g/min
Failure of cell membrane ion pumps, with loss of transmembrane electrochemical gradients
<10 mL/100 g/min
Cellular death