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
What is the primary mechanism for maintaining constant cerebral blood flow despite changes in systemic blood pressure?
AEndothelial factors
BBaroreceptor reflex
CMyogenic autoregulation
DMetabolic control
Which of the following physiologic changes decreases pulmonary vascular resistance (PVR)?
AInhaling the inspiratory reserve volume (IRV)
BExhaling the entire vital capacity (VC)
CExhaling the expiratory reserve volume (ERV)
DBreath holding maneuver at functional residual capacity (FRC)
EInhaling the entire vital capacity (VC)
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