Question

List and describe the Partial Pressures and Diffusion Gradients of both external and internal respiration. Include the direction of diffusion

Answer 1

External respiration

it represent the gaseous exchange occuring between the pulmonary capillaries and Lungs

Partial pressure of Oxygen in Alveolar air is 104mmHg and in Pulmonary capillary is 40mmHg.

Diffusion occurs from a higher partial pressure to lower partial pressure.

So oxygen diffuses from alveoli to the pulmonary capillary.

Partial pressure of carbo dioxide in alveoli is 40mmHg and in pulmonary capillary is 45mmHg

so carbon dioxide diffuses from pulmonary vein to Alveoli.

Internal Respiration

it represent the gaseous exchange between the systemic circulation and the tissue

Partial pressure of oxygen in systemic artery supplying the tissue is 95mmHg and partial pressure of oxygen in tissue is 40mmHg

So the oxygen diffuses from systemic artery to tissue

Partial pressure of carbon dioxide in the Sytemic artery is 40mmHg and in the tissue is 45mmHg

so the carbon dioxide diffuses from the tissue to systemic circulation