Biology Q-Pack 1 #35

[lightng]

During the initial skin diving session, when her heart and breathing rates were increased, Sarah noticed that she produced more urine than usual. This was most probably a result of:

A. Increased blood pressure caused by her excitement or anxiety
B. reduced blood pressure caused by her excitement or anxiety
C. absorption of water from the ocean
D. inability to cool the skin through evaporative water loss


The answer was A which confuses me because urine production occurs during PNS stimulation.

Is the line of reasoning simply that SNS leads to more urine ACCUMULATION and not necessarily the output itself? Is that what the question is referring to?

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[theonlytycrane]

The q-stem says heart and breathing rates increased so we're talking about the SNS. Now just go through each choice using POE.

(B) SNS activation wouldn't cause reduced BP.
(C) We don't absorb water from the ocean when we swim.
(D) Urine output and evaporative cooling are not really related.

Urine production may occur during PNS stimulation (not sure off the top of my head, would have to check), but we have to focus on the SNS based on the q-stem.

 

[wizzed101]

Higher BP -> more blood to the nephron-> more filtrate -> more urine

Nothing to do with SNS or PNS or whatever.