ESS2001 Physiology Chapter 8 exphys

ESS2001 Physiology Chapter 8 exphys Accumulation of metabolic by-products in muscle (H+, CO2, heat) leads to a. vasoconstriction b. vasodilation c. sympathetic activation d. reduced muscle blood flow - ANSWER b. vasodilation VO2max is likely to be limited by a. substrate availability b. H+ ion accumulation c. cardiac output d. all of these - ANSWER c. cardiac output During moderate exercise in the heat, which vascular beds receive the most blood flow? a. muscle, splanchinic (gut) b. muscle, renal (kidneys) c. muscle, skin d. muscle, brain - ANSWER c. muscle, skin Hyperventilation causes a. an increase in oxygen b. an increase in carbon dioxide c. a decrease in oxygen d. a decrease in carbon dioxide - ANSWER d. decrease in carbon dioxide Which of the following will decrease stroke volume? a. increased preload b. increased contractility c. increased Ca2+ concentrations d. increased afterload - ANSWER d. increased afterload If the ventilatory equivalent for oxygen starts to increase and at the same time the ventilatory equivalent for carbon dioxide does not increase, this means that a. aerobic metabolism is increasing b. ventilation is becoming more efficient c. anaerobic metabolism is increasing d. ventilation is not meeting oxygen demands of the body - ANSWER c. anaerobic metabolism is increasing The mechanism that underlies preload's effects on stroke volume is the a.Frank-Starling mechanism b. Hering-Breuer mechanism c. Willis mechanism d. end-diastolic mechanism - ANSWER a. Frank-Starling mechanism Which one of these increases in direct proportion to exercise intensity? a. diastolic blood pressure b. venous oxygen content c. systolic blood pressure d. arterial oxygen content - ANSWER c. systolic blood pressure Steady state heart rate can be used to a. determine tissue oxygen extraction b. estimate stroke volume during exercise c. predict aerobic capacity d. calculate anaerobic threshold - ANSWER c. predict aerobic capacity If dehydration causes hematocrit to rise to 60%, what is the consequence? a. enhanced exercise capacity due to higher red blood cell concentration b. enhanced exercise capacity due to lower blood viscosity c. diminished exercise capacity due to enhanced venous return d. diminished exercise capacity due to impeded blood flow - ANSWER d. diminished exercise capacity due to impeded blood flow The lactate threshold is best estimated using a. maximal voluntary ventilation b. anaerobic threshold c. EIAH d. venous PO2 - ANSWER b. anaerobic threshold Which of the following does NOT contribute to ventilatory regulation during exercise? a. chemoreceptors in the brain, carotid bodies, and lungs b. baroreceptors in the carotid sinus c. chemoreceptors in muscles d. stretch receptors in the right atrium - ANSWER b. baroreceptors in the carotid sinus During maximal exercise, how much cardiac output is redirected to muscles? a. 20% b. 40% c. 60% d. 80% - ANSWER d. 80% The most effective buffer in t