BMS 420 Lecture Notes - Reuptake, Macrophage, Lung Volumes
Document Summary
Vital capacity = total lung capacity residual volume. Minute volume = tidal volume x respiratory rate. Alveolar ventilation = (tidal volume dead space) x respiratory rate (500 150 ml) x rr = 350 x 12 = 4. 2 l/min. Physiological dead space = anatomical dead space + alveolar dead space. Low surface tension increases the compliance of lung and reduces work of breathing (irds: high surface tension, fluid filled lungs, collapsed lungs) Alveoli are more stable and there is less tendency for small alveoli to blow up big alveoli since the smaller alveoli would have less surface tension. Alveoli are kept at about the same size thus: good gas exchange, even ventilation. Alveoli with high surface tension will tend to collapse and hence draw fluid from capillaries into alveolar space. Surfactant reduces the surface tension thus preventing transudation of fluid. Collapse of alveoli is prevented by traction provided by surrounding alveoli. Pores of kohn and canals of lambert provide collateral ventilation.
