PSL301H1 Lecture Notes - Lecture 20: Hyperventilation, Atmospheric Pressure, Partial Pressure
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PSL301H1 Full Course Notes
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Physiological responses to high altitudes: physiological responses to exercise. High altitude is described as anything above 1500m. Group of researchers went up to mt everest to investigate what happens. 25% of people arriving at 2500m will exp high altitude sickness. Not necessarily due to how fit they are - can affect anyone. Atmospheric pressure at summit of mt everest is 253 mmhg. Hypoxia is the main problem - lack of oxygen because total barometric pressure is less. Air is 20% oxygen normally, so this is less at high altitudes. Partial pressure of o2 in dry air at 253 mmhg is: 53 mmhg. 253 mmhg x 0. 21 = 0. 21 53 mmhg. Chemoreceptors respond to inc level of protons in blood, but sensitivity is influenced by po2. Below shows change in ventilation with increasing pco2. During hypoxia, arterial pco2 would decrease due to hyperventilation.
