PNB 2250 Chapter Notes - Chapter 5: Allantois, Bundesautobahn 60, Desiccation
13 Sep 2016
School
Department
Course
Professor
Document Summary
Better oxygen extraction than tidal (back-forth) flow: air spaces/sacs. Do not provide lift: birds have a high oxygen consumption, air spaces make bones lighter, tracheal volume is large. 3x the ventilation of mammals: bird lung anatomy. From the trachea, 50% of the air goes to the posterior air sacs, 50% go to the anterior air sacs and lungs. Expired air goes to the air sacs (which contract) The expired air goes from the air sacs to the lungs, then to the trachea, to the anterior sac, and back to the trachea. Through lungs (bronchus) in both inhalation and exhalation. + during exhalation from the posterior air sacs. Oviparity: oviparous lay eggs outside the body; very little development maternally, insects. More protein softer shell: reptiles, birds, or monotremes (oviparous mammals) Non-oviparous, internal development, no need for shell: shells must be permeable to oxygen, water, and carbon dioxide.
