HYPOPHYSEAL PORTAL SYSTEM Meaning and
Definition
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The hypophyseal portal system is a circulatory network of blood vessels that connects the hypothalamus with the anterior pituitary gland, two vital structures located in the brain. It is an intricate and specialized arrangement of blood vessels consisting of a primary portal system and a secondary capillary network.
The primary portal system involves a bundle of blood vessels known as the hypothalamic portal veins, which start in the hypothalamus and extend down to the anterior pituitary gland. These veins carry hormones, or chemical messengers, produced by the hypothalamus into the anterior pituitary gland. These hormones, called releasing hormones or inhibiting hormones, stimulate or suppress the secretion of various hormones in the anterior pituitary gland. Therefore, this system ensures that hormones produced by the hypothalamus can directly reach their target cells in the anterior pituitary gland without dilution or filtration in the general circulation.
Upon entering the anterior pituitary gland, the hypothalamic hormones are then released into the secondary capillary network called the pituitary portal veins. This network surrounds the hormone-secreting cells of the anterior pituitary gland, allowing for close proximity and efficient transfer of hormones into the general circulation. Ultimately, the hormones released by the anterior pituitary gland regulate the function of a multitude of endocrine glands and organs throughout the body, maintaining a delicate balance of hormones necessary for normal physiological functions.
In summary, the hypophyseal portal system is a complex network of blood vessels that enables the direct communication and transport of hypothalamic hormones to the anterior pituitary gland, allowing for precise control of hormone secretion and regulation of various physiological processes throughout the body.
