Tuesday, March 24, 2009

Jill lives in Sydney. She decides to spend to spend three months of her holidays working in the Andes in Bolivia. What kind of respiratory and other

Mountain climbers have found that when they climb up a mountain slowly over a period of days, rather than a period of hours, they can withstand far lower atmospheric oxygen concentrations than when they ascend rapidly.

The event just described is acclimatization to the low oxygen. Jill's body would have to acclimatize to living in high altitude. The reason for this effect is that within 2 to 3 days the respiratory center in the brain stem loses about four fifths of its sensitivity to changes in arterial PCO2 (partial pressure of carbon dioxide) and hydrogen ions (Guyton & Hall, 2000).

The following sentences describe the events that would go through Jill's body as she adjusts to the height changes. The higher the altitude, the lower the oxygen in the air. Therefore, the excess ventilatory blow-off of carbon dioxide that would normally inhibit an increase in respiration now fails to do so, and the low oxygen can drive the respiratory system to a much higher level of alveolar ventilation than under short-term low-oxygen conditions (Ganong, 2001).

Instead of a 70% increase in ventilation that might occur on acute exposure to low oxygen, the alveolar ventilation often increases 400 to 500 % after two to three days of low oxygen (Guyton & Hall, 2000). This helps immensely in supplying additional oxygen to Jill.

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