system
Given the following post, respond as if you're commenting on Reddit:
human
Once urine is in the bladder, is there any way for the body to recoup the water in it?

Say your bladder is full of urine, but your body is also becoming dehydrated. Can it get anything useful out of the urine in the bladder without you having to pee it out?
gpt
The bladder is lined by a type of skin called transitional epithelium. The function of this type of epithelium is to allow it to expand and contract without leaking. This is because that is what the bladder is intended to do. The transitional epithelial cells are connected together by tight junctions, which form an essentially water-proof barrier intended to prevent toxic metabolites within the bladder from getting back into the body. Therefore, once it’s in the bladder, the fluid is essentially inaccessible to the rest of the body without some sort of pathologic process going on.