Answer :
Final answer:
The primary and secondary capillary plexuses and the intervening hypophyseal portal veins constitute the hypophyseal portal system. This system is essential for the transport of hypothalamic hormones directly to the anterior pituitary gland, bypassing the systemic circulation.
The correct answer is option 3. Hypophyseal Portal System
Explanation:
The primary and secondary capillary plexuses and the intervening hypophyseal portal veins make up the hypophyseal portal system. This network allows hypothalamic hormones to be transported to the anterior pituitary without first entering the systemic circulation. It originates from the superior hypophyseal artery, which branches off the carotid arteries and transports blood to the hypothalamus. Hormones then travel from the hypothalamus through a primary capillary plexus to the portal veins, which carry them into the anterior pituitary. In contrast to the hepatic portal system, which routes blood from the gastrointestinal tract and spleen through the hepatic portal vein to the liver for processing, the hypophyseal portal system is mainly involved in the regulation of hormonal activity.
