PYSO 001 Lecture Notes - Lecture 8: Pleural Cavity, Intrapleural Pressure, Thoracic Cavity
12 May 2020
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Contains heart, large blood vessels, trachea, esophagus, thymus, right and left lungs. Enclosed by 12 pairs of ribs joined at strum and vertebrae. Separated from abdominal cavity by dome shaped diaphragm muscle. Two membranes in close contact very little space in pleural sac. Filled with pleural fluid secreted by membrane cells lubricates lungs when they move. Puncture in sac allows it to fill with air lung collapses. Pleural sac air tight sac that separates each lung from thoracic wall. Cyclic pressure changes cause air to move in and out of lungs. Air moves from high to low pressure (moves down pressure gradient) Flow rate (f) = p/r, where p = pressure gradient, and r = resistance. Atmospheric pressure: pressure exerted by air above objects on earth"s surface. Atmospheric pressure as altitude (less air above you as move upward) During inspiration (inhalation) atmospheric pressure greater than intrapulmonary pressure air moves in.
