Thyroid and Adrenal Glands

2. Adrenal Glands

Overview of the Adrenal Gland

Situated atop each kidney, the adrenal glands consist of two distinct regions with different functions:

• The adrenal cortex, which secretes corticosteroids—including glucocorticoids (cortisol) for metabolism and stress response, mineralocorticoids (aldosterone) for electrolyte balance, and androgens that contribute to secondary sexual characteristics.
• The adrenal medulla, which releases epinephrine and norepinephrine, mediating the “fight or flight” response to stress.

The adrenal glands are regulated by the hypothalamic–pituitary–adrenal (HPA) axis and the autonomic nervous system, linking endocrine and neural control of stress adaptation and homeostasis.