ANATOMY

Detailed explanation-1: -SIADH happens when your body makes excess amounts of antidiuretic hormone (ADH). SIADH causes your body to retain too much water and commonly leads to hyponatremia, which is low levels of sodium in your blood.

Detailed explanation-2: -Deficiency of ADH is usually due to hypothalamic-neurohypophyseal lesions (central diabetes insipidus) or insensitivity of the kidney to ADH (nephrogenic diabetes insipidus). These patients, if untreated, have the predictable result of dehydration, hyperosmolality, hypovolemia, and eventual death in severe cases.

Detailed explanation-3: -Vasopressin (also called antidiuretic hormone) helps regulate the amount of water in the body by controlling how much water is excreted by the kidneys. Vasopressin decreases water excretion by the kidneys. As a result, more water is retained in the body, which dilutes the level of sodium in the body.

Detailed explanation-4: -antidiuretic hormone enhances the sequestration of sodium in the interstitial fluids of the medulla and papilla’. Importantly, vasopressin increased the absolute amount of sodium per unit of dry solids showing that increases in medullary sodium concentration were independent of effects on water.