Progressive Care Nursing Certification (PCCN) Practice Exam

Where is antidiuretic hormone (ADH) primarily formed?

1. Hypothalamic supraoptic nuclei

2. Juxtaglomerular cells

3. Pineal gland

4. Posterior pituitary

The correct answer is: Hypothalamic supraoptic nuclei

Antidiuretic hormone (ADH), also known as vasopressin, is primarily formed in the hypothalamic supraoptic nuclei. This region of the hypothalamus synthesizes ADH, which is then transported down the axons to be stored and released from the posterior pituitary gland into the bloodstream. Understanding the synthesis and secretion of ADH is crucial in the context of fluid balance and osmolarity regulation in the body. The hypothalamus plays a key role in homeostasis, and the supraoptic nuclei are specifically responsible for producing this important hormone. When the body experiences dehydration or increased osmolarity, this hormone is released to promote water reabsorption in the kidneys, thus helping to conserve water and concentrate urine. The other options refer to different structures that do not synthesize ADH: the juxtaglomerular cells, located in the kidneys, primarily produce renin; the pineal gland is responsible for melatonin secretion; and while the posterior pituitary does store and release ADH, it does not produce it. This distinction highlights the specific role of the hypothalamus in the physiological regulation of fluid balance.