questions 2

Response to Exercise

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Topic updated on 02/28/16 2:31pm

Overview
  • ↑ O2 demand ↑ respiratory rate and ↑ tidal volume ↑ minute ventilation
  • ↑ O2 consumption and ↑ CO2 production
  • Arterial blood
    • no change in PaO2 and PaCO2
      • ↑ minute ventilation and ↑ efficiency of gas exchange ensure that there is neither a decrease in PaO2 nor an increase in PaCO2
    • ↓ pH during strenuous exercise
      • secondary to lactic acidosis
  • Venous blood
    • ↑ PvCO2
      • skeletal muscle adds more CO2 than usual to venous blood
    • no change in PaCO2
      • sufficient ↑ minute ventilation to remove excess CO2
  • Pulmonary blood flow
    • ↑ cardiac output → ↑ pulmonary blood flow ↓ pulmonary resistance
      • pulmonary blood flow becomes more evenly distributed throughout lungs
      • V/Q ratio from lung apex to lung base becomes more uniform
        • ↓ physiologic dead space
  • Oxygen-hemoglobin dissociation curve
    • ↑ tissue PCO2, ↓ tissue pH, and ↑ temperature shifts to right
      • ↓ hemoglobin affinity for O2 ↑ O2 unloading in exercising skeletal muscle


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AVERAGE 4.0 of 7 RATINGS

Qbank (1 Questions)

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(M1.PL.23) A person is exercising strenuously on a treadmill for 1 hour. An arterial blood gas measurement is then taken. Which of the following are the most likely values? Topic Review Topic

1. pH 7.38, PaO2 100, PCO2 69 HCO3 42
2. pH 7.36, PaO2 100, PCO2 40, HCO3 23
3. pH 7.32, PaO2 42, PCO2 50, HCO3 27
4. pH 7.56, PaO2 100, PCO2 44, HCO3 38
5. pH 7.57 PaO2 100, PCO2 23, HCO3 21

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