Final answer:
The posterior pituitary is connected to the hypothalamus via a bridge of nerve axons, which carry hormones like vasopressin and oxytocin for storage and secretion. This structure, consisting of nerve fibers and neuroglial cells, extends from the hypothalamus down the infundibulum to the posterior pituitary.
Step-by-step explanation:
The posterior pituitary, also known as the neurohypophysis, forms an anatomic connection with the hypothalamus through a bridge of nerve axons. These nerve axons belong to neurons that originate in the paraventricular and supraoptic nuclei of the hypothalamus. The cell bodies of these neurons are located within the hypothalamus, but their axons extend down through the pituitary stalk, also known as the infundibulum, and end in the posterior pituitary gland. This connection allows for the transportation and storage of hypothalamic hormones such as vasopressin and oxytocin within the posterior pituitary, which is then secreted into the bloodstream when needed.
Contrastingly, the anterior pituitary, or adenohypophysis, connects with the hypothalamus by a set of capillaries forming the hypophyseal portal system. The anterior pituitary synthesizes and secretes its hormones in response to releasing and inhibiting hormones delivered from the hypothalamus through this blood vessel network. This demonstrates the different anatomical relationships between the anterior and posterior lobes of the pituitary gland and the hypothalamus.