neurohipófise

The neurohypophysis, also known as the posterior pituitary gland, is the posterior lobe of the pituitary gland. It is composed of nervous tissue and is essentially an extension of the hypothalamus. Unlike the anterior pituitary, the neurohypophysis does not synthesize hormones itself. Instead, it stores and releases hormones that are produced in the hypothalamus. These hormones are synthesized by neurosecretory cells in specific hypothalamic nuclei, primarily the supraoptic and paraventricular nuclei. These hormones then travel down the axons of these neurons to the neurohypophysis, where they are stored in nerve terminals.

The two primary hormones released by the neurohypophysis are antidiuretic hormone (ADH), also called vasopressin, and oxytocin. ADH plays a crucial role in regulating water balance by increasing water reabsorption in the kidneys, thus concentrating urine and preventing dehydration. Oxytocin is involved in social bonding, childbirth (stimulating uterine contractions), and lactation (triggering milk ejection). The release of these hormones from the neurohypophysis is controlled by electrical signals from the hypothalamus, which are influenced by various physiological stimuli such as changes in blood osmolarity for ADH and social cues or physical stimulation for oxytocin. The neurohypophysis is functionally and anatomically linked to the hypothalamus via the hypothalamo-hypophyseal tract.