A 40-year-old female volunteers for an invasive study to measure her cardiac function. She has no previous cardiovascular history and takes no medications. With the test subject at rest, the following data is collected using blood tests, intravascular probes, and a closed rebreathing circuit: Blood hemoglobin concentration 14 g/dL Arterial oxygen content 0.22 mL O2/mL Arterial oxygen saturation 98% Venous oxygen content 0.17 mL O2/mL Venous oxygen saturation 78% Oxygen consumption 250 mL/min The patient's pulse is 75/min, respiratory rate is 14/ min, and blood pressure is 125/70 mm Hg. What is the cardiac output of this volunteer?
ABody surface area is required to calculate cardiac output.
BStroke volume is required to calculate cardiac output.
C250 mL/min
D5.0 L/min
E50 L/min
A scientist is trying to design a drug to modulate cellular metabolism in the treatment of obesity. Specifically, he is interested in understanding how fats are processed in adipocytes in response to different energy states. His target is a protein within these cells that catalyzes catabolism of an energy source. The products of this reaction are subsequently used in gluconeogenesis or β-oxidation. Which of the following is true of the most likely protein that is being studied by this scientist?
AIt is stimulated by epinephrine
BIt is inhibited by glucagon
CIt is inhibited by acetylcholine
DIt is inhibited by cortisol
EIt is stimulated by insulin
During exercise, what is the primary mechanism for increased oxygen delivery to active muscles?
ADecreased blood viscosity
BIncreased cardiac output
CIncreased hemoglobin affinity
DEnhanced oxygen diffusion
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