Partial pressure

Definition

Partial pressure is the pressure exerted by a single type of gas in a mixture of gases. It is proportional to its concentration in the mixture and is essential for understanding gas exchange in biological systems.

5 Must Know Facts For Your Next Test

1. Partial pressures drive the diffusion of gases across respiratory surfaces, such as alveolar membranes in the lungs.
2. Oxygen and carbon dioxide each have their own partial pressures that determine their movement into and out of blood and tissues.
3. The sum of all partial pressures equals the total atmospheric pressure.
4. Partial pressure gradients between alveoli and capillaries facilitate gas exchange during respiration.
5. Henry's Law states that at constant temperature, the amount of a gas dissolved in a liquid is directly proportional to its partial pressure.

Review Questions

• How does partial pressure influence the diffusion of oxygen and carbon dioxide across respiratory surfaces?
• What happens to gas exchange if there is no significant partial pressure gradient between alveolar air and blood?
• According to Henry's Law, how does an increase in partial pressure affect the solubility of a gas in a liquid?

Related terms

Diffusion:

The process by which molecules move from an area of higher concentration to an area of lower concentration.

Alveoli: Tiny air sacs within the lungs where gas exchange occurs.

Hemoglobin:

A protein in red blood cells that binds oxygen for transport through the bloodstream.