How does the Hypothalamic-Pituitary Axis Function?
The HPA functions through a series of feedback mechanisms. The hypothalamus releases specific hormones into the hypophyseal portal system, a specialized blood vessel network connecting the hypothalamus and anterior pituitary. These hormones then stimulate or inhibit the release of pituitary hormones. For example, CRH from the hypothalamus stimulates the anterior pituitary to secrete ACTH, which in turn stimulates cortisol release from the adrenal gland. This cortisol exerts negative feedback on both the hypothalamus and anterior pituitary to regulate hormone levels.
