Which gland is primarily responsible for the secretion of cortisol?

Cortisol is primarily secreted by the adrenal cortex, which is the outer layer of the adrenal glands located on top of each kidney. The adrenal cortex is responsible for producing several hormones, including glucocorticoids like cortisol, which plays a crucial role in metabolism, immune response regulation, and stress response.

Cortisol production is stimulated by adrenocorticotropic hormone (ACTH) from the pituitary gland, but the actual synthesis and release of cortisol occur in the adrenal cortex. This process is part of the body's response to stress, helping to maintain homeostasis by regulating various physiological functions such as glucose metabolism, blood pressure, and inflammation.

The other glands listed have distinct roles in hormone secretion: the pituitary gland regulates other endocrine glands by secreting various hormones, including ACTH; the thyroid gland is primarily responsible for the production of thyroid hormones that regulate metabolism; and the pancreas produces insulin and glucagon for blood sugar regulation. Therefore, the adrenal cortex is the correct answer when identifying the primary source of cortisol secretion.