Question

required information
at the arterial end of a tissue capillary, rank the following structures from highest to lowest ( p_{o 2} ).
multiple choice
capillaries, tissue fluid, cells
cells, tissue fluid, capillaries
cells, capillaries, tissue fluid
tissue fluid, capillaries, cells
the ( p_{o 2} ) is the same in all three.

Explanation:

Oxygen diffuses from an area of higher partial pressure to an area of lower partial pressure. At the arterial end of a tissue capillary, capillaries have oxygen - rich blood. Oxygen then diffuses from capillaries to tissue fluid (due to concentration gradient), and then from tissue fluid to cells (as cells consume oxygen in cellular respiration).

Answer:

Capillaries, tissue fluid, cells