What exactly tells us we need to pee, and how is the duration of when we need to pee set?

Question

Or rather what speeds up the point of needing to pee?

I know the body part that does it, but what chemical/reaction makes it happen and how so?

*Honestly, I don’t know if my words are making sense, I hope someone understands.*

In: Biology

Answer 1

Your bladder is like a balloon. The balloon gets filled (with urine) and when it’s about half way full, stretch receptors in the wall of the balloon starts sending signals to your brain that you need to pee. When you pee the balloon empties itself, and kinda deflates, meaning the stretch receptors are no longer sending signals to the brain about it You start to feel the urge to pee when the bladder contains 300-400ml of urine.