A 24-year-old professional athlete is advised to train in the mountains to enhance his performance. After 5 months of training at an altitude of 1.5 km (5,000 feet), he is able to increase his running pace while competing at sea-level venues. Which of the following changes would produce the same effect on the oxygen-hemoglobin dissociation curve as this athlete's training did?
ADecreased 2,3-bisphosphoglycerate
BIncreased carbon monoxide inhalation
CDecreased temperature
DDecreased pH
EIncreased partial pressure of oxygen
A 24-year-old woman presents to the emergency department after she was found agitated and screaming for help in the middle of the street. She says she also has dizziness and tingling in the lips and hands. Her past medical history is relevant for general anxiety disorder, managed medically with paroxetine. At admission, her pulse is 125/min, respiratory rate is 25/min, and body temperature is 36.5°C (97.7°F). Physical examination is unremarkable. An arterial blood gas sample is taken. Which of the following results would you most likely expect to see in this patient?
ApH: increased, HCO3-: increased, Pco2: increased
BpH: decreased, HCO3-: decreased, Pco2: decreased
CpH: decreased, HCO3-: increased, Pco2: increased
DpH: increased, HCO3-: decreased, Pco2: decreased
EpH: normal, HCO3-: increased, Pco2: increased
A 52-year-old man undergoes an exercise stress test for a 1-week history of squeezing substernal chest pain that is aggravated by exercise and relieved by rest. During the test, there is a substantial increase in the breakdown of glycogen in the muscle cells. Which of the following changes best explains this intracellular finding?
AActivation of phosphorylase kinase
BDecrease in protein kinase A
CInactivation of glycogen synthase kinase
DActivation of protein phosphatase
EIncrease in glucose-6-phosphate
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