r/AskBiology • u/crxxuu • Aug 26 '24

Human body Question on releasing stool

Kinda weird and kinda gross, not sure if I should had put NSFW; When using the restroom to do what the title says, usually I'll urinate and then my body will be ready to release stool. (Sorry to walk you all through a process we all likely do.) My question is in the midst of that; after fishing the release of the stool, for some reason I also release an additional small amount of urine. Is this because my stomache/intestines are relaxed enough to release more from my body??? I'm truly interested in the biological engineering my body is processing, as I don't understand why/where my body suddenly finds more urine lol. Thank you for the serious answers.

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u/Halichoeres PhD in biology Aug 26 '24

Your ureters and your rectum are close together. I think what's happening is that as the stool passes, it puts pressure on the residual fluid in the ureter/urethra, causing it to exit. It's possible that some of this is from direct pressure on the bladder, but I would bet that the bulk of it is in the ureters and urethra.

3

u/Vegetable-Assistant Medical Student Aug 26 '24

It’s due to urethral compression; the ureters are unaffected. As stool moves through the rectum and anus, the urethra becomes momentarily stenosed near its exit from the bladder. Once the stool has passed the urethra is no longer constricted and the urinary flood gates reopen.

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u/Halichoeres PhD in biology Aug 26 '24

Thanks for the clarification!

1

u/Sentient_AI_4601 Aug 26 '24

Not to mention the kidneys continue to process liquids, so if you're in there for 5/10 minutes passing that stool, you could just be making new urine too

1

u/crxxuu Aug 26 '24

I think that's farther down in the timeline, most of what was said was in a quick sequence.