Comparative Vertebrate-Cardiovascular System

Comparative Vertebrate-Cardiovascular System - For...

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For organisms that are aquatic and breathe air, there is secondary circuit Amphibians evolved from basal to advanced… Used skin as respiratory organism Separate respiratory surfaces Get most of oxygen from gills or lungs Modern day amphibians, dump Carbon dioxide across skin Blood flow supporting the skin, becomes respiratory structure Pulmonary arch starts to get new branch, Cutaneous artery Pulmoncutaneous artery splits to feed lung in one direction and skin in the other direction Fewer reduced arches Increased use of skin, lose ductus arteriousus Reptiles/Birds/Mammals Separate Pulmonary and Systemic circuit (right and left) Reptiles Pulmonary artery and vein No cutaneous respiration Scales allowed them to separate from water Systemic circuit has dual systemic ventral aorta o Important in aspiration; sometimes go through apnea Dual systemic aorta will merge into one aorta behind heart Single aorta arch come from each ventricle Birds Systemic arch that gives rise to aorta, is derived from right systemic arch in reptiles Endothermic Mammals Single systemic arch Systemic arch that give rise to aorta, is derived from left systemic arch in reptiles Endothermic Lampreys and Ostracoderms had ansillary hearts Hearts Early Fish Has one atrium and one ventricle, but also has sinus venosus and bulbis cordis Linear flow system (four chambers) o Sinus venosus atria ventricle bulbis cordis Have auto rhythmisity heart have ability to beat on their own o SA Node found in sinus venosus
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Valves o Chambers are separated by these o Flow is one way o Low resistance, passive valves meaning… Small changes in pressure can cause lots of flow Valve opens and closes according to the pressure across the chamber Blood is pumped in a unidirectional flow Oxygenated blood is dumped into the venous system
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Comparative Vertebrate-Cardiovascular System - For...

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