Which of the following statements about cerebral blood flow distribution in the awake adult is correct?
- A Gray matter receives roughly twice the flow per unit weight of white matter ✓
- B Gray and white matter receive equal flow per unit weight
- C White matter receives greater flow per unit weight than gray matter
- D Flow is uniform throughout the hemisphere regardless of activity
Correct answer: A. Gray matter receives roughly twice the flow per unit weight of white matter
Explanation
Average cerebral blood flow is about 50 mL per 100 g per minute, but this conceals marked regional variation: gray matter receives roughly 70 to 80 mL per 100 g per minute while white matter receives about 20 mL per 100 g per minute, so cortical flow is nearly three to four times subcortical flow. Local flow also increases in metabolically active regions during specific tasks, demonstrating coupling between neuronal activity and perfusion.
Reference: Guyton and Hall Textbook of Medical Physiology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.