key term - Posterior pituitary gland

Definition

The posterior pituitary gland, also known as the neurohypophysis, is a part of the pituitary gland located at the base of the brain. It primarily stores and releases two important hormones, oxytocin and vasopressin (also called antidiuretic hormone or ADH), which are synthesized in the hypothalamus. This gland plays a vital role in regulating various physiological processes such as water balance and reproductive functions.

5 Must Know Facts For Your Next Test

1. The posterior pituitary gland does not produce hormones itself; instead, it stores and releases hormones produced by the hypothalamus.
2. Oxytocin is often referred to as the 'love hormone' because it is involved in social bonding, sexual reproduction, and childbirth.
3. Vasopressin acts to conserve water in the body, and its release is triggered by increased blood osmolarity or low blood volume.
4. Disorders related to the posterior pituitary can lead to conditions such as diabetes insipidus, which is characterized by excessive urination and thirst due to insufficient ADH.
5. The posterior pituitary gland is regulated by neural signals from the hypothalamus, which allows for rapid responses to changes in the body's homeostasis.

Review Questions

• How does the posterior pituitary gland contribute to the regulation of water balance in the body?
  • The posterior pituitary gland regulates water balance primarily through the secretion of vasopressin (ADH). When blood osmolarity increases or blood volume decreases, osmotic sensors in the hypothalamus stimulate the release of ADH from the posterior pituitary. This hormone acts on the kidneys to increase water reabsorption, helping to dilute blood plasma and restore homeostasis.
• Evaluate the roles of oxytocin and vasopressin released from the posterior pituitary gland in human physiology.
  • Oxytocin and vasopressin play crucial roles in human physiology. Oxytocin facilitates uterine contractions during labor and promotes milk ejection during breastfeeding, contributing to reproductive health and maternal bonding. Vasopressin regulates water retention in kidneys, influencing fluid balance and blood pressure. Together, these hormones exemplify how the posterior pituitary integrates neural signaling with hormonal control over vital body processes.
• Analyze how dysfunctions in the posterior pituitary gland can lead to systemic health issues, including diabetes insipidus.
  • Dysfunctions in the posterior pituitary gland can significantly impact systemic health, particularly through improper secretion of vasopressin. In cases like diabetes insipidus, insufficient ADH results in an inability to concentrate urine, leading to excessive urination and increased thirst. This condition can cause severe dehydration and electrolyte imbalances, highlighting how critical hormonal regulation from this gland is for maintaining homeostasis and overall health.

Related terms

Oxytocin: A hormone released by the posterior pituitary gland that stimulates uterine contractions during childbirth and promotes milk ejection during breastfeeding.

Vasopressin (ADH): A hormone released by the posterior pituitary gland that helps regulate water balance in the body by increasing water reabsorption in the kidneys.

Hypothalamus:

A region of the brain that produces hormones regulating many bodily functions, including those released by the posterior pituitary gland.