Hormone pathway: Osmoregulation(increased blood osmolarity)

• Stimulus: insufficient water intake or excessive loss through through sweating, vomiting, or diarrhoea, diabetes, kidney dysfunction, diuretic use
• Osmoreceptors in the hypothalamus detect high blood osmolarity
• hypothalamus : signals the posterior pituitary to release antidiuretic hormone (ADH) into the bloodstream
• Kidneys: ADH increase the permeability of the collecting ducts, promoting water reabsorption
• Response: water is retained, diluting blood solutes and lowering osmolarity, less water is excreted, making urine more concentrated 
• Feedback: as blood osmolarity decreases, the stimulus for ADH release is reduced. This prevents excessive water retention and maintains osmotic balance