PHGY 312 Lecture Notes - Lecture 9: Carotid Body, G Cell, Alkalosis
24 May 2016
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Vo2" = ve" x (cio2 ceo2) Vo2" = ve" cio2 [(cio2 ceo2)/cio2] O2 used = o2 delivered x o2 extraction. Decrease in oxygen consumption when hypoxia kicks in. Encephalic structures of the brain and carotid bodies can sense hypoxia. Blood skimming and bifurcation: hct value of branches not the same as parent vessels, depends on bifurcation shape. Glomous cells are sensing directly proportional to po2, it means that even if there are huge changes in the carrying capacity of blood, they don"t feel it. Mutations in hemoglobin, blood loss, anemia, co poisoning. All change the carrying capacity of the blood but the g cells will not sense it. Evolution: variations in pressure, not content are sensed. Spiracles in insects will open in hypoxia. If done in low pco2 without correcting for bicarbonate (alkalosis), then you get a sigmoidal. The 2 curves are about the same meaning that receptors feel pco2 because we"re changing ph.
