Physiology 3120 Lecture Notes - Lecture 2: Pulmonary Compliance, Lung Volumes, External Intercostal Muscles
20 Jan 2017
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Document Summary
Process by which air moves in and out of the lungs. Via changing pressure within the lung cavity: move diaphragm up/down, expand/compress rib cage. Active process (contraction of inspiratory muscles: the diaphragm, the external intercostals (rib cage) Increase pressure gradient between lung and intrapleural space inflation. Normal process (normally: lung and chest wall return to their equilibrium position. Active process (exercise or spontaneous hyperventilation: muscles of the abdominal wall, the internal intercostals. Ability of lung to expand with relatively small changes in pressure. Due to the distensibility of the lung. Allows inhalation of large volume with small changes in pressure. Termed for this is property lung compliance (or pulmonary compliance) Defined as volume change per unit pressure change. Can be determined by creating a pressure-volume curve. At each pressure applied using syringe, volume is measured. Pressure (cm h2o) bc water was used instead of mercury (mmhg)
