posterior pituitary

Examples of posterior pituitary in the following topics:

• The Posterior Pituitary

  • The posterior pituitary secretes two important endocrine hormones—oxytocin and antidiuretic hormone.
  • The posterior pituitary (or neurohypophysis) comprises the posterior lobe of the pituitary gland and is part of the endocrine system.
  • The posterior pituitary is composed of two parts:
  • The posterior pituitary stores two hormones secreted by the hypothalamus for later release:
  • Identify the location of the posterior pituitary and the hormones associated with it

• Control of the Pituitary Gland by the Hypothalamus

  • The pituitary gland consists of the anterior pituitary and the posterior pituitary.
  • The pituitary gland consists of two components: the anterior pituitary and the posterior pituitary, and is functionally linked to the hypothalamus by the pituitary stalk (also named the infundibular stem, or simply the infundibulum).
  • Whilst the pituitary gland is known as the master endocrine gland, both of the lobes are under the control of the hypothalamus: the anterior pituitary receives its signals from the parvocellular neurons, and the posterior pituitary receives its signals from magnocellular neurons.
  • The posterior lobe of the pituitary gland develops as an extension of the hypothalamus.
  • The anterior and posterior lobes of the pituitary (hypophysis) gland are shown.

• Hypothalamic-Pituitary Axis

  • The hypothalamus, an endocrine organ, regulates the anterior pituitary gland and transports hormones along the posterior pituitary gland.
  • The pituitary has two distinct regions: the anterior pituitary and the posterior pituitary.
  • The posterior pituitary is significantly different in structure from the anterior pituitary.
  • The posterior pituitary and the infundibulum together are referred to as the neurohypophysis.
  • Describe the hormones released by the anterior posterior pituitary and their effects on the body

• Overview of the Pituitary Gland

  • The pituitary gland, or hypophysis, is an endocrine gland about the size of a pea.
  • The pituitary is functionally connected to the hypothalamus by a small tube called the infundibular stem, or, pituitary stalk.
  • The pituitary gland secretes hormones that regulate homeostasis.
  • The pituitary gland is divided into two parts, the anterior pituitary and the posterior pituitary.
  • The posterior pituitary does not produce any hormones of its own, rather, it stores and secretes two hormones made in the hypothalamus—oxytocin and anti-diuretic hormone.

• Overview of Endocrine Glands

  • A collection of endocrine glands makes up the endocrine system: the pituitary (anterior and posterior lobes), thyroid, parathyroid, adrenal (cortex and medulla), pancreas and gonads.
  • The pituitary gland consists of two major regions, the anterior pituitary gland (adenohypophysis) and the posterior pituitary gland (neurohypophysis).
  • Communication between the hypothalamus and the posterior pituitary occurs through neurosecretory cells that span the short distance between them.
  • Hormones produced by the cell bodies of the neurosecretory cells are packaged in vesicles and transported through the axon and stored in the axon terminals that lie in the posterior pituitary.
  • Differentiate among the types of endocrine glands (pituitary [posterior pituitary, anterior pituitary], thyroid, parathyroid, adrenal, and pancreas) in the endocrine system

• The Anterior Pituitary

  • A major organ of the endocrine system, the anterior pituitary (also called the adenohypophysis) is the glandular, anterior lobe of the pituitary gland.
  • The fleshy, glandular anterior pituitary is distinct from the neural composition of the posterior pituitary.
  • The anterior pituitary is composed of multiple parts:
  • Pars distalis: This is the distal part that comprises the majority of the anterior pituitary; it is where most pituitary hormone production occurs.
  • Pars intermedia: This is the intermediate part that sits between the pars distalis and the posterior pituitary and is often very small in humans.

• Regulation of Urine Concentration and Volume

  • Antidiuretic hormone (ADH), produced by the pituitary gland, controls the amount of water that is reabsorbed through the collecting ducts.
  • ADH is a hormone secreted from the posterior pituitary gland in response to increased plasma osmolarity (ie. increased ion concentration in the blood), which is generally due to increased concentration of ions relative to volume of plasma, or decreased plasma volume.
  • The increased plasma osmolarity is sensed by osmoreceptors in hypothalamus, which will stimulate the posterior pituitary gland to release ADH.
  • A common example is alcohol and water ingestion, which directly inhibit ADH secretion in the pituitary gland.

• Hormonal Regulation of the Excretory System

  • The anterior pituitary is composed of glandular cells that secrete protein hormones.
  • The pituitary gland has two components: anterior and posterior.
  • The posterior pituitary is an extension of the hypothalamus.
  • The hypothalamus produces a polypeptide hormone known as antidiuretic hormone (ADH), which is transported to and released from the posterior pituitary gland.
  • If the posterior pituitary does not release enough ADH, water cannot be retained by the kidneys and is lost as urine.

• Hormonal Regulation of the Reproductive System

  • Male and female gonads are regulated by FSH and LH from the pituitary; their production is stimulated by GnRH, secreted by the hypothalamus.
  • At the pituitary, GnRH stimulates the synthesis and secretion of the gonadotropins, FSH and LH.
  • The posterior pituitary releases the hormone oxytocin, which stimulates uterine contractions during childbirth.
  • Oxytocin release is stimulated by the suckling of an infant, which triggers the synthesis of oxytocin in the hypothalamus and its release into circulation at the posterior pituitary.
  • GnRH, secreted by the hypothalamus, stimulates the production of FSH and LH from the pituitary gland.

• Pituitary Gland Disorders

  • Disorders of pituitary gland can affect hormones which regulate growth and activity of other glands in the body.
  • The pituitary is a "small, pea-sized gland" located at the base of the brain .
  • Most of the hormones in the anterior pituitary are each part of an axis that is regulated by the hypothalamus.
  • The hormones of the posterior pituitary are produced in the hypothalamus and are carried by nerve endings to the posterior lobe.
  • There are multiple ways of treating pituitary adenomas.