I’ve often wondered this. It would be in a situation where someone drank a lot, but then was dehydrated after her body had already filtered the excess water into the bladder. I’m inclined to think that the body couldn’t reabsorb the water from the urine, since I’ve woken up having to pee and feeling thirsty.
The bladder cannot reabsorb fluids in any significant way. It’s basically a muscular container, designed to collect urine and expell it.
QtM, MD
You can always drink your urine again, of course…
Desert tortoises store water in their urinary bladders. During the monsoon season in S. Arizona, tortoises will get into emphemeral pools and pump water into their bladders through the cloacal opening. (the one opening where digestive wastes, excretory wastes, and reproductive cells exit the body normally). In a well hydrated tortoise, approximately 1/3rd of the body mass is due to water stored in the bladder. This water can be taken up into the bloodstream and used sparingly as required.
If handled, the animal may void the bladder. This poses a long term survival problem, as the water may not be replaced for some time, which can be too late here in the desert. So please, if you see one of these critters, just say Hi and go on about your business.
Oh…you mean human bladders? I don’t know.
Heh, my human-bladder question was already answered, so I thank you for that wonderful bit of information. I’ll remember to leave desert tortoises alone!
Mini-hijack: It seems like voiding the water when disturbed would be a terrible behavior. What if a predator annoys it? I’m assuming it could just go up into its shell, but then die from dehydration? It seems that sort of behavior would get stamped out pretty fast.
Whats the evolutionary advantage of pissing all over your predator and then dying of thirst?
Right, but how exactly big is a ureter, exactly? Doesn’t it seem like maybe urine in the bladder could diffuse around a bit and water could come back up them into the kidney where anti-diuretic hormone could allow that water back into the blood?
I’m sensing an experiment coming on!
Speaker for the Dead, you’re the one who asked, so it stands to reason that you’ll be the one to carry this out, of course…
It would have to be in an environment with selective pressure in favor of spite.
Purely anecdotal, this, but I remember reading an interview with a Formula 1 driver (I think it may have been Jenson Button) in which he said that before a race drivers would drink litres of water and be busting for a pee, but because it got so hot and they’d get so dehydrated during the race, by the end they wouldn’t need to go any more.
Then again, that could be just a euphemism for “We piss in the car” :eek: