BSCI 207 Lecture Notes - Lecture 23: Exhalation, Trachea, Bird Anatomy
24 Oct 2018
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Bsci 207, dr. bretton kent - wednesday, october 24, 2018. Small, specialized body plans (channels, septate, flattened to increase sa) No specialized respiratory structures (just vary body shape) Specialized fractal repiratory surfaces (gills and lungs) Diffusion & passive (movement of environment over body) bulk flow inadequate. Ventilation- bulk flow of respiratory medium (air or water) Use water siphon to harness jet power. Exhalation- contracts circular muscles, water sprays out. Water and blood flow in opposite directions (counter current) Most efficient method of exchange as equilibrium does not hinder diffusion when fluids move in opposites. 2 ventilation pumps (in through mouth and gills at different times) Air is advantageous over water in many ways. Diffusion primarily by air, uses water to moisten membranes. No counter current flow, air isn"t moving during diffusion. Inhalation- air pumped into lungs by muscles (positive pressure) Air sacs temporarily store air during breathing. 2 complete inhalation-exhalation cycles per breath, continuous flow.
