BIO 203 Lecture Notes - Lecture 16: Countercurrent Exchange, Trachea, Respiratory System
8 Dec 2017
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Two most important gases: oxygen and carbon dioxide. Active fish uses more o2 than inactive fish. Warm water carries less o2 than cold water. O2 consumption increases as water temperature increases. Concentration: volume per volume, or quantity of gas. Partial pressure: proportion of total atmospheric pressure of a gas. 20. 95% o2, 79. 05% other, fully humidified air. Ph2o at 25 c = 25 mm hg, at 37 c = 40 mm hg. O2 partial pressure (po2) under humidified conditions: at 25 c: = (760-25) mm hg 0. 2095, = 154 mm hg at 37 c: = (760-40) mm hg 0. 2095, = 151 mm hg. Thoracic cavity expands intrapleural pressure becomes less negative lungs expand. Gases in lungs are expelled intrapleural pressure becomes less negative lungs contract. Avian bronchial tree and air sacs lung is divided into numerous parabronchi. Primary and secondary bronchi connect the lung to the air sacs. Air flow through bird lungs unidirectional in parabronchi.
