BISC 101 Study Guide - Final Guide: Modes Of Mechanical Ventilation, Countercurrent Exchange, Buccal Pumping
11 Dec 2017
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Lecture 17: gas exchange & circulation i: define ventilation. Diffusion o2/co2 move b/w air/h2o & blood at respiratory surface. Transport gases throughout body cells & tissues: describe gas exchange in the air. O2 = plentiful (21% at sea level) Only extract 25% air inhaled: describe gas exchange in h20. H20 through mouth & out gill cover (operculum) Ventilation occurs by pumping mouth (buccal pumping) or swimming (ram ventilation) Gill = 4 arches each with 2 filaments each with thousands of gill lamellae. Positive partial pressure gradient exists along whole length lamella. Air filled tubes (trachea) branch throughout body + air sacs. Smallest = tracheoles reach individual cells w fluid filled tips. Changing vol/pressure of chest cavity drives negative pressure ventilation: describe inhalation. Diaphragm moves down and vol increases/decreased pressure. Intercostal muscles contract & pull ribs up/out: describe exhalation. Active muscle tissues use o2 and produces co2. Ph [co2] of cerebrospinal fluid & ph sensors in major blood vessels (carotid bodies)
