Direct measurements of oxygen tension at the surface of arterioles, capillaries and venules of the cerebral cortex

Abstract
Direct pO2 measurements were made at the surface of arterioles, capillaries, and venules of rabbit brain cortex. The results indicate that a considerable amount of oxygen diffuses through the arteriolar and precapillary wall. Therefore, the arterial blood that reaches the capillaries already has low pO2 (43±3 mm Hg and about 75%–70% of the blood oxygen capacity).