What does the sensation of thirst result from?
A poorly localized area of the hypothalamus called the "thirst center" is stimulated by a dry mouth as well as body dehydration, Projections from the thirst center to the thalamus and then to the conscious cortex inform us that we need water. This triggers the sensation of thirst and initiates the conscious desire for water. The hypothalamus also takes subconscious steps to correct dehydration.
When you begin to become dehydrated is thirst sensation a part of a negative or positive feedback control system?
Negative feedback, because thirst drives you to drink, which reduces the original condition, dehydration. A positive feedback would increase the original condition, such as being praised for performing an action would result in performing the action more often, in order to get more praise (like getting points here results in persons answering more questions in order to get more points! :) ).
Water leaves the body continuously as urine, sweat and respiration, in addition to being used for digestive and energy expenditure of normal activities. Since this output is ongoing, your body can sense when your blood is becoming too concentrated with electrolytes and stimulates nerve centers in the hindbrain of the brainstem to cause the sensation of thirst. This feedback mechanism keeps the blood within a specific range of concentration, though this sensation of thirst is…
Well right now, Thirst 4 just came out on August 9. If you can't find Thirst, The Last Vampire is the same series but individualized stories instead of three part combined books. Thirst One- The Last Vampire, Black Blood, and Red Dice. Thirst Two- Phantom, Evil Thirst, and Creatures of Forever. Thirst Three- The Eternal Dawn. Thirst Four- The Shadow of Death.