PSL301H1 Lecture Notes - Lecture 17: Tidal Volume, Hypocapnia, Hypercapnia
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PSL301H1 Full Course Notes
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** increased co2 levels is the main trigger for breathing** Blackout activity triggered by decreased o2 levels in blood. Increased o2 levels has a limit until hemoglobin saturation. Increase [co2] increase ventilation: the increased ventilation decreases [co2], thus bringing [co2] to normal and stopping the ventilation response (negative feedback) Co2: main factor for control, because it"s faster to change than oxygen (oxygen is associated with hemoglobin), whereas co2 simply dissolves in plasma, factors affecting co2 concentration, respiratory rate, tidal volume (volume in each breath) Hypercapnia: abnormally high co2 (more than 45 mmhg) Hypocapnia: abnormally low co2 (less than 35 mmhg) Normal o2 concentrations linear relationship b/w pco2 ventilation. Mild hypoxia (decreased o2 concentration: steeper response to pco2 changes, a smaller increase in co2 pressure elicits higher ventilation rate, takes smaller changes in co2 to elicit same change in ventilation. Severe hypoxia (very low o2 concentration: almost vertical relationship, tiny increase in co2 pressure elicits much higher ventilation rate.
