The brain, not the body, tells us that our thirst is quenched.

1. When the body is dehydrated, the brain tells us to drink

1.1. There is an area of brain cells known as the "thirst center"

1.1.1. These cells can tell us we aren't thirsty anymore

1.1.1.1. Animals stop drinking long before their bodies have a chance to absorb the liquid

1.1.1.1.1. Hydration of the body takes 10-15 min, but animals normally stop drinking within one min

1.1.1.2. We have to stop drinking or we will consume too much, which is unhealthy

1.1.2. The thirst center acts like a water meter, measuring the amount of fluid intake

1.1.3. Cells in the thirst center sense dehydration and make us feel thirsty

1.1.4. Brain figures out that liquid is on the way and sends signal that quenches thirst, even though body is still dehydrated.

1.1.4.1. Brain cells can tell difference between fast muscle movement of gulping vs. slow pace of swallowing

1.1.4.2. In mice study, "thirst center" cells only fired when the mouse was drinking water, but not while eating

1.1.4.3. Additionally, if these same cells are stimulated in a thirsty animal, they can completely stop drinking water

1.1.4.3.1. Through these experiments on basic functions, scientists can now tweak specific brain circuits