A 35-year-old male presents with severe dehydration following prolonged exercise without fluid intake. Vital signs show BP 95/60, HR 118, RR 20, and serum osmolality 310 mOsm/kg. Urine specific gravity is 1.035 with minimal urine output. He denies diuretic use. His kidneys respond by increasing aquaporin-2 channel insertion into collecting duct principal cell apical membranes, enhancing water reabsorption. Which hormone mediates this adaptive response?
- A)Parathyroid hormone
- B)Antidiuretic hormoneGABARITO
- C)Renin
- D)Aldosterone
- E)Atrial natriuretic peptide
Explicação
Antidiuretic hormone binds V2 receptors on collecting duct principal cells and promotes insertion of aquaporin 2 channels into the apical membrane. This increases water reabsorption and helps concentrate the urine during dehydration. Ver explicação completa e trilha adaptativa →