Mr. Smith with a history of hypertension is diagnosed with primary hyperaldosteronism. This diagnosis indicates that the patient's hypertension is caused by excessive hormone secretion from which of the following glands?

The correct answer is the adrenal cortex because primary hyperaldosteronism, also known as Conn's syndrome, is a condition characterized by the overproduction of the hormone aldosterone, which is secreted by the adrenal cortex. Aldosterone plays a crucial role in regulating blood pressure by promoting sodium retention, which in turn leads to increased water retention and higher blood volume.

In primary hyperaldosteronism, the excessive secretion of aldosterone contributes directly to the hypertension experienced by the patient, as the body retains more fluid, causing an increase in blood pressure levels. Understanding the source of hormone production is vital in diagnosing the underlying cause of conditions like hypertension.

The other glands listed do not produce aldosterone. The adrenal medulla primarily secretes catecholamines (like epinephrine and norepinephrine), which are involved in the fight-or-flight response. The pancreas produces insulin and glucagon, integral to glucose metabolism, while the parathyroid glands regulate calcium levels in the body. Therefore, they do not relate to the condition of primary hyperaldosteronism and its effect on hypertension.