**2. Disorders of sodium homeostasis**


• Osmoreceptors are hypothalamic neurons that are responsible for adjusting thirst and vasopressin secretion based on plasma sodium. Vasopressin binds to V2 receptors on the principal cells lining the renal collecting duct [3]. In the presence of vasopressin, water is allowed to flow out of the collecting tubule in the nephron attracted by a high solute concentration of the surrounding medullary interstitium. When plasma sodium is high, vasopressin levels are also increased.
