BIOL 379 Lecture 10: Bird Anatomy
Document Summary
Air sacs no exchange of gases (only the lungs do this), tested by filling a sac with carbon monoxide and tying it off had no effect on the bird, some sacs penetrate into the marrow of bones. Air enters posterior air sac on 1st inhale 1st exhale pushes air into lungs . 2nd inhale air moves into anterior air sacs 2nd exhale air exits system. System provides completely fresh air every time (no residual volume), one way flow = better air. Schmidt + nelson discovered this through research on ostriches. Trachea syrinx (similar function to larynx in humans) sits @ branching of bronchi. High pressure system some birds have died from heart attacks just from stress. Heart is 2x as large comparatively but beats at speed of mammals. Diving birds drop their heart rate & constrict blood flow to sensory & endocrine organs to conserve oxygen. Temperature: 41* c or 105* f requires more heat, sometimes enter torpor @ night.
