Cardiac Vascular Nursing Certification Practice Exam 2026 – Your All-in-One Guide to Exam Success!

The release of antidiuretic hormone (ADH), also known as vasopressin, primarily enhances water reabsorption in the kidneys. When ADH is secreted from the posterior pituitary gland in response to factors such as increased plasma osmolality or lower blood volume, it acts on the renal collecting ducts and distal convoluted tubules to facilitate the reabsorption of water back into the bloodstream.

By increasing the permeability of the kidney tubules to water, ADH allows more water to be absorbed, leading to concentrated urine and a decrease in urinary output. This mechanism helps maintain fluid balance, blood pressure, and overall homeostasis in the body.

The other options pertain to different physiological processes. Sodium excretion typically involves mechanisms associated with natriuretic peptides rather than ADH, while potassium retention is mainly regulated by aldosterone. Calcium absorption is primarily influenced by parathyroid hormone and vitamin D, not directly by ADH. Thus, the role of ADH is clearly aligned with enhancing water reabsorption, making it the correct choice here.