Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: John Chapman on 01/03/2009 22:01:07

Title: How does drinking quench your thirst?
Post by: John Chapman on 01/03/2009 22:01:07

If you are thirsty, that thirst can be immediately quenched by drinking water. However, my understanding is that the mechanism of thirst is controlled by an increase in osmotic pressure which is detected by osmoreceptors. I would guess these are to be found in the hypothalamus, which seems to control these sort of homeostatic processes.

It must take a considerable time for changes in the concentration gradient to travel from the stomach to the intestine, from there to diffuse into the bloodstream and finally to the osmoreceptors within the brain. So my question is this?

How does drinking quench your thirst so quickly?

Title: How does drinking quench your thirst?
Post by: neilep on 01/03/2009 22:21:47

Dearest Mr Chapman,

Great questions !!...brilliant question !..someone here once asked the same question http://www.thenakedscientists.com/forum/index.php?topic=5297.0  not too sure if the answer was resolved and so I would also like to know the answer of your thirst orientated question. What a great question !..a question of merit !

Title: How does drinking quench your thirst?
Post by: John Chapman on 01/03/2009 22:51:23

Ha ha ha. I thought you were congratulating me but it was YOU who asked the question first time round!

Well, it wasn't really answered in detail so I'll leave this one posted. There were some interesting comments made, though, and I may try to quote from it if I figure out how to quote from one thread into another. [:-\]

Title: How does drinking quench your thirst?
Post by: neilep on 01/03/2009 23:04:22

LOL..  [;D]I suppose I was being just a tad cheeky   [;)]. In fact, I kind of ' dejavued' myself some time later by asking the same question again here http://www.thenakedscientists.com/forum/index.php?topic=6577.0 however, as you can see, a definitive answer is still required so I am grateful very muchly for your newer far more eloquent version. Lets hope it gets an answer this time !  [;)]

Title: How does drinking quench your thirst?
Post by: John Chapman on 01/03/2009 23:23:09

Karen W made an interesting observation in neilp's thread:

Quote from: Karen W. on 14/09/2006 19:10:18

My skin gets dry and feels less soft when I am dehydrated. So when I am drinking 84 ozs a day, my skin becomes very smooth and my complection improves by leaps and bounds, less blemishes etc. Interesting, although I would like to know the mechanics behind it too

Karen

I would guess (and it is just a guess) that this has less to do with hydration and more to do with toxins removed by the renal system. The kidneys help maintain fluid concentration and blood pressure within the body but this goes hand in hand with their job facilitating excretion of nitrogenous waste and other metabolic waste products. I believe that the more water they filter out then the more toxins are also filtered. By drinking a lot you are effectively turning up their volume.

Title: How does drinking quench your thirst?
Post by: John Chapman on 01/03/2009 23:28:54

Quote from: neilep on 01/03/2009 23:04:22

In fact, I kind of 'dejavued' myself some time later by asking the same question again here http://www.thenakedscientists.com/forum/index.php?topic=6577.0

Bloody hell, Neil. You're just rubbing salt in the wound, now. And here was me thinking I still had some shred of originality left! [;)]