a-short-review-of-histology

The Blood Vessels of The Pituitary Gland:

The pituitary gland receives its arterial blood supply from branches of the internal carotid artery
The capillaries which are abundant throughout the pituitary gland are fenestrated which allows easy delivery of the hormones produced by the secretory cells of the pituitary gland into the general circulation
However, these fenestrations also allow hormones to pass from the circulation into the pituitary gland and this includes regulatory hormones which are stimulatory/inhibitory to pituitary hormone production/secretion
Many of the stimulatory/inhibitory factors for the hormones produced in the anterior pituitary gland are derived from cells located in the hypothalamus
There are no direct cellular connections between the hypothalamus and the anterior pituitary, as there is between the posterior pituitary and the hypothalamus
Delivery of these regulatory hormones is facilitated by a portal circulation which is known as the hypophysioportal circulation