What is the Most Potent Stimulus of the Thirst Mechanism

Question

What is the most potent stimulus of the thirst mechanism?
A)atrial natriuretic peptide (ANP)
B)osmolarity of the ECF
C)increased blood pressure
D)increased plasma volume

Accepted Answer

The osmolarity of the extracellular fluid (ECF) is the most potent stimulus of the thirst mechanism. When there is an increase in osmolarity, the hypothalamus detects this change and triggers the release of antidiuretic hormone (ADH) to conserve water and stimulate thirst. This is why we feel thirsty when we eat something salty or when we are dehydrated. Atrial natriuretic peptide (ANP), increased blood pressure, and increased plasma volume can all have the opposite effect of inhibiting the thirst mechanism.