Question

Explain how partial pressure differences between the cell and the capillary result in the movement of those gases between the cell and the capillary?

Answer 1

Answer : inhaled oxygen moves from the alveoli to the blood in the capillaries and CO2 moves from the blood in the capillaries to the air in the alveoli. This gas exchange mainly happens by simple diffusion.

The direction of movement of gases determined by the relative concentration gradient which is created through partial pressure for each across the membrane.

gas molecules move from high concentration area to the low concentration area.

Partial pressure is the measure of concentration of the individual component in a mixture of gases . The total pressure exerted by the mixture is the sum of the partial pressure if the components. The rate of diffusion of a gas is directly proportional to its partial pressure within the total gas mixture.

According to Fick's law

Rate of diffusion =KA(P2-P1/D)

Here K= gas diffusion constant

A= the area of gas exchange

p2-P1= the difference in partial pressure of gas on

Either side of the diffusion barrier

Distance across which the gas must diffuse.