Question

Briefly describe Boyle’s, Dalton’s, and Henry’s laws as they relate to respiration. Give an example how each law can used to explain some alterations in respiratory function.

Answer 1

Boyel's law states that at constant temperature the volume of a gas is inversely proportional to its pressure. Which means when volume decreases the pressure increases and vice-versa. During inhalation the muscles increase the size of thoracic cavity which expand the lungs which leads to increase in volume due to which pressure inside the lungs decreases due to this air in the atmosphere rushes into the lungs as pressure outside is more than inside of lungs and due to pressure gradient the air flow from outside to inside of lungs. During exhalation the muscles decrease the size of thoracic cavity and this decreases the volume due to which pressure inside the lungs increases because of which air rushes out of the lungs from an area of higher pressure to area of lower pressure.

Dalton’s law states that the total pressure exerted by the mixture of inert gases is equal to the sum of the partial pressures of individual gases in air. In respiration Dalton's law states that partial pressures of gases does not change when the pressure and volume of the gas mixture changes hence during inhalation the air in lungs will have the same relative partial pressure of gasses as in atmosphere.

Henry’s law states that the amount of a gas which dissolves in a liquid is directly proportional to the partial pressure of that particular gas. In respiration Henry’s law states how the gasses will dissolve in the alveoli and bloodstream during the process of gaseous exchange. The amount of oxygen which dissolves into the blood is directly proportional to the partial pressure of oxygen in the alveolar air. As partial pressure of oxygen is greater in alveolar air when compared to the deoxygenated blood hence oxygen dissolves into deoxygenated blood. Whereas carbon dioxide has a greater partial pressure in deoxygenated blood when compared to alveolar air hence it diffuses out of blood into the air.