PSIO 420 exam 4 key

PSIO 420 exam 4 key - PSIO 420/520 practice problem set#4...

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PSIO 420/520 practice problem set #4: The cardiovascular system and thermoregulation 1. How would the following conditions affect stroke volume? Justify each answer. Condition: Effect on SV: An increase in tidal volume. decrease increase no effect Why? The in negative thorax pressure draws blood ( respiratory pump) resulting in an preload_____ An increase in PNS activity. decrease increase no effect Why? Assuming contractility is unaffected, the in HR via in PNS activity will filling time, thus preload Moving from a supine to upright position. decrease increase no effect Why? Venous return (preload) is hindered by gravity when moving to an upright position ___________________ Dehydration. decrease increase no effect Why? Dehydration is a in plasma volume which results in a in preload ___________________________ 2. Plot the change in stroke volume that you would expect to measure during a progressive intensity exercise test performed to exhaustion by an untrained person (include appropriate values and units). Then, explain the reason for the change that is observed as it relates to the three determinants of stroke volume. 120 Preload increases due to reasons in part b, but it is_____ SV (ml/beat) hindered by the increase in HR. The increase in_______ 70 contractility is likely offset by the increase in MAP.____ .3 VO2 (L/min) 3 b. What three mechanisms facilitate an increase in venous return during progressively intense exercise? 1.
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This note was uploaded on 05/13/2008 for the course PSIO 420 taught by Professor Keen during the Spring '08 term at Arizona.

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PSIO 420 exam 4 key - PSIO 420/520 practice problem set#4...

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