PATHOLOGY

Detailed explanation-1: -Fluid Osmolality and Na+ Concentration. It has long been recognized that thirst is stimulated by increases in the extracellular concentration of nonpermeable osmolytes, such as Na+, that cause osmotic movement of water from body cells.

Detailed explanation-2: -If your body doesn’t produce enough ADH or your kidneys don’t respond to it, your body loses too much water in urine output. Signs of low ADH include: Excessive thirst. Frequent urination.

Detailed explanation-3: -Subtle changes in plasma osmolality are the most potent stimulus for thirst. In response to increases in osmolality, osmoreceptors activate release of the neurohormone vasopressin (also known as antidiuretic hormone).