Okay kiddo, so first we need to talk about a hormone called vasopressin. Vasopressin is a chemical that your body releases when you need to hold onto water.
Your body has these things called vasopressin receptors, which are like tiny doors on your cells that the vasopressin can open to tell your body what to do.
Now when your body has enough water, the vasopressin isn't needed much and it can just hang out without doing too much. But when your body needs to hold onto water, the vasopressin will go find those receptors and open them up.
So these vasopressin receptors are really important for helping your body hold onto water and keep you hydrated. Without them, your body might get dehydrated really easily!