KINE 3012 Lecture Notes - Lecture 4: Oxygen Saturation, Blood Gas Tension, Extracellular Fluid
11 Feb 2018
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In lungs, capillaries (blood) has the lowest pressure for o2. In tissues, capillaries have highest pressure for o2. How hemoglobin increases o2 transport: addition of hemoglobin decreases blood po2. Equilibrium is achieved in alveoli and blood when all hemoglobin are saturated and dissolved pressures in two compartments are equal: hb keeps pressure of o2 as low as possible. What determines o2 carrying capacity: total amount of hb, po2 (alveolar & arterial) Hemoglobin saturation and po2: as oxygen pressure increases, saturation increases. As oxygen binds to hb, it changes its conformation & thus making other hb more accessible to o2- thus i(cid:374)(cid:272)reases h(cid:271)"s affi(cid:374)it(cid:455) for oxygen positive feedback. Po2 in lungs is high (100mmhg) greater affinity. In systematic capillaries, pressure is low & lower affinity for o2. Still of oxygen still in blood in tissue. Saturation of oxygen to hb drops b/c pressure is lower in tissue: at sea level pao2= 100mmhg, pao2=100mmhg 100% saturation.
