Lung compliance and stability: compliance of the lung, degree to which lung expands/fills for change in transpulmonary pressure (pressure betw pleural space and alveolar space) 2: small compliance in the beginning ii. Prior birth results in respiratory distress syndrome in premature babies: alveolar stability, laplace"s law, p = (2t)/r, pressure inside bubble equal to 2x surface tension (t) divided by radius. Soapy bubble floating in ar has inside surface and outside surface so 2x factor becomes 4x. In 2 connected alveoli, according to this law smaller alveolus w/ greater pressure will give air to larger alveolus with less pressure. 5 cm h2o outward gradient keeps them open: functions of surfactant stability, reduces surface tension on inside of alveolus, contributing to alveolar, reduced surface tension increases lung compliance. Reduces energy required to make every breath: prevents pulmonary edema. T collapses alveoli and pulls water (from caps) into interstitial space, and then into alveolar space: marangoni effect.