BIOL211 Lecture Notes - Lecture 4: Branchial Arch, Gas Exchange, Mecha

• School: University of Waterloo
• Department: Biology
• Course: BIOL211
• Professor: Dayeh Vivian

Document Summary

Living in water: has some challenges (4, adjusting buoyancy. Trying to stay in water column: maintain body temp, maintenance of stable internal environment --> due to movement of water & ions, limits on gas exchanges --> e. g. o2. Ventillation mech: 2 ways fishes ventilate --> pass h2o across gills so gas exchange occurs, buccal pumping --> mouth & opercular cavities pump h2o across gills due to. Pump h2o to have max o2 extraction: ram ventilation --> fish swims w/ mouth open to pass h2o across gill. Force h2o into mouth & gills (mouth is always open: many pelagic (open ocean fishes) & filter feeding fish do this. Sometimes o2 level in water is low --> need to have another way to get required o2: use lungs or accessory air respiratory structures, oxygenated blood leaves (high o2, deoxygenated blood enters (low o2) Countercurrent flow maintains o2 [ ] (= diffusion gradient) btwn blood &