PSL301H1 Lecture Notes - Lecture 6: Altitude Sickness, Atmospheric Pressure, Pulmonary Artery
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PSL301H1 Full Course Notes
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25% of people at ~2500 get high altitude sickness. Consider: barometric pressure at the summit of mt everest: 253mmhg. Po2= barometric pressure x percent of oxygen in air. Recall: ventilation + arterial pco2 have a positive relationship ( ventilation, arterial pco2) At lower po2, the relationship ( ventilation, arterial pco2) has a steeper slope. In other words, in hypoxia (lower po2), ventilation increases even at the slight increase/ buildup of arterial pco2. Co2 + h2o h2co3 h++hco3 (hyperventilation = quickly getting rid of co2, Ph) ( ph requires po2 in order to saturate hb) Longer term physiological responses: release of erythropoeitin make more rbc, synthesis of 2,3- dpg in rbc. Vomiting: bc cerebral autoregulation of blood flow. Ataxia: lose control of bodily movements. Perfusion pumping liquid into organ/ tissue normal mismatch. Ventilation of gas out of alveoli is matched with perfusion of liquid into organ/ tissue. Within alveoli: pco2, po2 local control mechanisms. Local blood vessels in the area will.
