PHSL 3051 Lecture Notes - Lecture 21: Capacitance, Vital Capacity, Vascular Resistance
Document Summary
Compliance: change in pressure needed to expand the lungs, ability to stretch. Requires a lower pressure change to inflate lungs. Pathologically high compliance in emphysema due to tissue destruction. Requires larger pressure change to inflate the same extent as compliant lungs. Elastance: elastic recoil, ability to return to resting volume when stretching force is released. Characteristics of the tissue can decrease compliance. Allows water particles to stick together via hydrogen bonding. Surface tension is seen in the beading of water on a slick window. High surface tension makes alveoli more likely to collapse. Different sized alveoli have different collapsing pressures with equal surface tension (no surfactant) Surfactant lower surface tension and lowers it more in the small alveoli so that pressures equal. Law of laplace: if two different alveoli have the same surface tension, the small bubble will have higher pressure. Mix of proteins and phospholipids - amphipathic: pos and neg charges; polarity. Decreases surface tension more in smaller alveoli.
