Question

Now let's look at a cell, with a typical pO2 of 40 torr located next to a capillary containing arterialized plasma with a normal pO2 of 100 torr. Let the next container represent the alveolus, filled with inhaled gas, with a pO2 of 100 torr. They sit side by side separated only by the capillary wall and by the alveolar wall. Of course, in reality, plasma moves between the alveolus and tissues as the heart pumps.

We know gases are permeable, so they move randomly in both directions, but the net diffusion of gases will be in which direction? Explain what happens to plasma pO2 as oxygen moves from plasma to cells? As a result, what happens to diffusion across the alveolar wall?

Answer 1

answer

here the cells needs oxygen for their funcction and for producing energy. the po2 of cell is 40 torr or mmhg.

which means the pressure excerted by oxygen inside cell is 40 mmhg. the capillary contain artreialized plasma with po2 100 mmhg. and next to this contain alveolus filled with po2 100 mmhg.

normaly gases will diffuse from high partial pressure region to low partial pressure region. so here the oxygen in the capillary will diffuse into the cells . so that po2 of cappilary blood will decreases . and it causes diffusion of oxygen from nearby alveoli into the blood through semipermiable membrane untill an equilibrium reached. so at the time of oxygen moves from plasma into cells , the diffusion of oxygen across the alveolar wall increases.