ANP 1105 Lecture Notes - Lecture 8: Intrapleural Pressure, Thoracic Wall, Lipoprotein

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1105
• Professor: William Staines

Document Summary

Rises and falls with breathing but eventually equalizes with atmospheric pressure. Movements of the thoracic wall will decrease the pressure momentarily. Slight net negative pressure within the pleural cavity, from contraction of the intercostal cavities. 4 mm hg lower than intrapulmonary pressure. Has to maintain a vacuum because the lung needs to stay inflated and stuck. Any condition that causes the intrapleural pressure and the pressure within the lung will cause it to collapse; one lung can collapse while the other one doesn"t. Surface tension of pleural fluid and elasticity of chest wall. Pressure increases as the lung expands more; a greater compliance. Water has a high surface tension and would cause the alveoli to. Surfactant is a detergent like lipoprotein produced by type ii cells; it interferes with the cohesion of the water molecules. Infant respiratory distress syndrome (irds): premature babies don"t produce enough surfactant and the alveoli have to be re-inflated with every breath.