BIOA02H3 Lecture Notes - Circulatory System, Extracellular Fluid, Pulmonary Artery
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BIOA02H3 Full Course Notes
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49. 2 how have vertebrate circulatory systems evolved? www. notesolution. com vertebrates have closed circulatory systems and hearts with two or more chambers. In adult amphibians, the pulmonary and systemic circuits are partially separated. The heart has three chambers: a single ventricle pumps blood to the lungs and to the rest of the body, two atria receive blood returning to the heart. therefore, blood form both sides of the ventricle flows through both aortas to the systemic circuit. Birds and mammals have fully separated pulmonary and systemic circuits: separate circuits have several advantages for active animals with continuously high metabolic rates. oxygenated and deoxygenated blood cannot mix; therefore, the systemic circuit always receives blood with the higher oxygen content. respiratory gas exchange is maximized because the blood with the lowest oxygen content and highest co2 content is sent to the lungs.