The organ responsible for releasing hormones that regulate the anterior pituitary is:

• A. Posterior pituitary
• B. Hypothalamus
• C. Adrenal cortex
• D. Thyroid gland

Answer: (B)

The hypothalamus regulates the anterior pituitary by releasing releasing and inhibiting hormones into the hypothalamic-pituitary portal system. This specialized blood vessel connection delivers these hypothalamic signals directly to the anterior pituitary, where they control the secretion of its hormones (such as TSH, ACTH, GH, PRL, LH, and FSH). The anterior pituitary’s activity is thus driven by these hypothalamic cues, making the hypothalamus the organ responsible for releasing the regulatory hormones.

The posterior pituitary, in contrast, stores and releases oxytocin and vasopressin that are made in the hypothalamus but does not regulate the anterior pituitary. The adrenal cortex and thyroid gland are target organs acted upon by anterior pituitary hormones, not regulators of the anterior pituitary itself.