BIO 3302 Lecture Notes - Lecture 2: Cytosol, Qrs Complex, Stroke Volume
2 Nov 2016
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Document Summary
With increasing o2 uptake, see: shift from water- to air-breathing, shift towards increasing separation of oxy and deoxy circulation, shift towards increasing blood pressure and flow. 2 loops - one for lungs and one for systemic circulation. Complete division of the circuits (each circuit has a pump: reptiles. Blood vessels to lungs and blood vessels to tissues but only one pump. 2 circuits one pump, arrives in some air-breathing fish. Gills between heart and systemic circulation in single circulation: 2 resistance beds in series. Blood needs to pump enough to recover resistance from lung area where blood vessels are small and tissues where blood vessels are small. Pump needs to be forceful enough to get through two sites of resistance: fragility of gill limits overall pressure. They are fragile bc need to be permeable to o2 in water. Pressure needs to be somewhat low to save gills. 2 separate circuits with 2 separate pumps that are housed together.
