Neurohypophysis

Neurohypophysis

The Neurohypophysis is a major component of the human endocrine system, specifically the pituitary gland. It is the posterior lobe of the pituitary gland and is primarily responsible for the storage and release of two crucial hormones, vasopressin (also known as antidiuretic hormone, ADH) and oxytocin.

Structure

The neurohypophysis consists of the pars nervosa, the infundibular stalk (also known as the pituitary stalk), and the median eminence. These structures are composed of glial cells and unmyelinated axons of neurons located in the hypothalamus.

Function

The primary function of the neurohypophysis is the storage and release of hormones produced by the hypothalamus. These hormones are transported down the axons in the infundibular stalk and stored in the pars nervosa until they are needed.

Vasopressin

Vasopressin is a hormone that regulates the body's water balance. It does this by controlling the amount of water reabsorbed by the kidneys. When the body is dehydrated, vasopressin is released, causing the kidneys to conserve water and produce less urine.

Oxytocin

Oxytocin is a hormone that plays a crucial role in childbirth and lactation. It stimulates the contraction of the uterus during labor and the release of milk during breastfeeding. Oxytocin is also involved in social bonding and has been dubbed the "love hormone" due to its association with pair bonding, empathy, and trust.

Clinical significance

Dysfunction of the neurohypophysis can lead to a number of medical conditions. For example, diabetes insipidus can occur if the neurohypophysis does not produce enough vasopressin, leading to excessive urination and thirst. On the other hand, syndrome of inappropriate antidiuretic hormone (SIADH) can occur if too much vasopressin is produced, leading to water retention and hyponatremia.

See also

• Adenohypophysis
• Hypothalamic–pituitary–somatic axis
• Hypothalamic–pituitary–adrenal axis
• Hypothalamic–pituitary–gonadal axis

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