BIO 121 Lecture Notes - Lecture 21: Furcula, Hemoglobin, Air Sacs
10 Dec 2020
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Document Summary
Consists of the two clavicles (collar bones) fused together. Along with keeled sternum and large pectoral (breast) muscles provides strength for flight movements. Bird respiratory system: adapted for flight metabolism. Birds breathe using small lungs: have 9 air sacs. Air sacs don"t exchange gases with blood; they store oxygenated air. Act as bellows, pushing fresh air into the lungs. Mammals: o2 rich air in, o2 poor air out- rich and poor air mixed in lungs. Birds: constant (unidirectional) flow of o2 rich air through lungs; more efficient. On;y o2 rich air contacts blood vessels; take fewer breaths. Bird hemoglobin holds more o2 than mammals hemoglobin. Ratites (order struthioniformes) one group of paleoghathae. 4-chambered heart with single aortic arch: independently evolved from birds. Diaphragm; hair; mammary glands; sweat glands; secondary palate- enables suckling. Most reptiles use throat, rib movements or other muscles for breathing. Coordinated movements of most of body act to ventilate lungs.
