Physical Principles Governing Gas Exchange

Gas behavior plays a vital role in understanding bodily processes such as external and internal respiration. External respiration involves the diffusion of oxygen into the blood and carbon dioxide out of it in the lungs. In contrast, internal respiration happens in body tissues, where these gases move in opposite directions.

Gas Laws Governing Respiration

The behavior of gases is guided by Dalton's Law of partial pressures and Henry's Law.

Dalton's Law asserts that the total pressure exerted by a mixture of gases equals the sum of the pressures each gas would exert independently. The partial pressure of each gas is directly proportional to its percentage in the mixture.

Henry's Law states that if a gas will dissolve in a liquid, is directly proportional to the partial pressure of the gas in contact with the liquid. This means that the quantity and rate at which a gas dissolves in a liquid depends on the gas's concentration. This principle also applies to the exchange of gases in the lungs and tissues. Notably, the solubility of a gas in a liquid and the temperature of the liquid also impact how much gas will dissolve at any given partial pressure.

Practical Applications of Gas Laws

These gas laws have significant practical applications. Hyperbaric oxygen chambers, which contain oxygen at pressures higher than 1 atm, force more oxygen into the blood of patients with carbon monoxide poisoning, illustrating Henry's Law.