located at or near or behind a part or near the end of a structure
of or relating to the pituitary gland; "pituitary hormone"
the master gland of the endocrine system; located at the base of the brain (同)pituitary_gland, pituitary body, hypophysis
any of various organs that synthesize substances needed by the body and release it through ducts or directly into the bloodstream (同)secretory organ, secretor, secreter
Pituitary gland. Posterior pituitary is in blue and Anterior pituitary is in orange. Pars nervosa and infundibular stalk are not labeled, but pars nervosa is at bottom and infundibular stalk is at top.
Median sagittal through the hypophysis of an adult monkey. (Posterior lobe labeled at bottom right.)
Details
Precursor
Neural tube (downward-growth of the diencephalon)[1]
Artery
inferior hypophyseal artery
Vein
hypophyseal vein
Identifiers
Latin
Pars nervosa glandulae pituitariae, pars nervosa hypophyseos, lobus posterior hypophyseos
MeSH
D010904
NeuroNames
401
NeuroLex ID
birnlex_1586
TA
A11.1.00.006
FMA
74628
Anatomical terminology
[edit on Wikidata]
The posterior pituitary (or neurohypophysis) is the posterior lobe of the pituitary gland which is part of the endocrine system. The posterior pituitary is not glandular as is the anterior pituitary. Instead, it is largely a collection of axonal projections from the hypothalamus that terminate behind the anterior pituitary, and serve as a site for the secretion of neurohypophysial hormones (oxytocin and vasopressin) directly into the blood.[2] The hypothalamic–neurohypophyseal system is composed of the hypothalamus (the paraventricular nucleus and supraoptic nucleus), posterior pituitary, and these axonal projections.[2]
Contents
1Structure
2Function
2.1Hormone secretion
3Clinical significance
4See also
5References
6Additional images
7External links
Structure
The posterior pituitary consists mainly of neuronal projections (axons) of magnocellular neurosecretory cells extending from the supraoptic and paraventricular nuclei of the hypothalamus. These axons store and release neurohypophysial hormones oxytocin and vasopressin into the neurohypophyseal capillaries, from there they get into the systemic circulation (and partly back into the hypophyseal portal system). In addition to axons, the posterior pituitary also contains pituicytes, specialized glial cells resembling astrocytes assisting in the storage and release of the hormones.[3]
Classification of the posterior pituitary varies, but most sources include the two regions below:
Pars nervosa
Also called the neural lobe or posterior lobe, this region constitutes the majority of the posterior pituitary and is the storage site of oxytocin and vasopressin. Sometimes (incorrectly) considered synonymous with the posterior pituitary, the pars nervosa includes Herring bodies and pituicytes.[4]
Infundibular stalk
Also known as the infundibulum or pituitary stalk, the infundibular stalk bridges the hypothalamic and hypophyseal systems.
The median eminence is only occasionally included as part of the posterior pituitary. Other sources specifically exclude it from the pituitary.[5]
A few sources include the pars intermedia as part of the posterior lobe, but this is a minority view. It is based upon the gross anatomical separation of the posterior and anterior pituitary along the cystic remnants of Rathke's pouch, causing the pars intermedia to remain attached to the neurohypophysis.
Function
Hormone secretion
Two hormones are classically considered as being related to the posterior pituitary: oxytocin and vasopressin. These hormones are created in the hypothalamus and released in the posterior pituitary. After creation, they are stored in neurosecretory vesicles regrouped into Herring bodies before being secreted in the posterior pituitary via the bloodstream.
Hormone
Other names
Symbol(s)
Main targets
Effect
Source
Oxytocin
OT
Uterus, mammary glands
Uterine contractions; lactation
supraoptic and paraventricular nuclei
Vasopressin
Antidiuretic hormone
VP, AVP, ADH
Kidneys and arterioles
Stimulates water retention; raises blood pressure by contracting arterioles
supraoptic and paraventricular nuclei
Clinical significance
Insufficient secretion of vasopressin underlies diabetes insipidus, a condition in which the body loses the capacity to concentrate urine. Affected individuals excrete as much as 20 liters of dilute urine per day. Oversecretion of vasopressin causes the syndrome of inappropriate antidiuretic hormone (SIADH).
See also
This article uses anatomical terminology; for an overview, see anatomical terminology.
Anterior pituitary
References
^Embryology at unc.edu
^ abMalenka RC, Nestler EJ, Hyman SE (2009). "Chapter 10: Neural and Neuroendocrine Control of the Internal Milieu". In Sydor A, Brown RY (ed.). Molecular Neuropharmacology: A Foundation for Clinical Neuroscience (2nd ed.). New York: McGraw-Hill Medical. pp. 246, 248–259. ISBN 9780071481274. •The hypothalamic–neurohypophyseal system secretes two peptide hormones directly into the blood, vasopressin and oxytocin. ... •The hypothalamic–pituitary–adrenal (HPA) axis. It comprises corticotropin-releasing factor (CRF), released by the hypothalamus; adrenocorticotropic hormone (ACTH), released by the anterior pituitary; and glucocorticoids, released by the adrenal cortex. •The hypothalamic–pituitary–thyroid axis consists of hypothalamic thyrotropin-releasing hormone (TRH); the anterior pituitary hormone thyroid–stimulating hormone (TSH); and the thyroid hormones T3 and T4. •The hypothalamic–pituitary–gonadal axis comprises hypothalamic gonadotropin–releasing hormone (GnRH), the anterior pituitary luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and the gonadal steroids.
^Hatton, GI (September 1988). "Pituicytes, glia and control of terminal secretion" (PDF). The Journal of Experimental Biology. 139: 67–79. PMID 3062122.
^Histology image:14004loa from Vaughan, Deborah (2002). A Learning System in Histology: CD-ROM and Guide. Oxford University Press. ISBN 978-0195151732.
^Median+eminence at the US National Library of Medicine Medical Subject Headings (MeSH)
Additional images
The posterior pituitary comprises the posterior lobe of the pituitary gland.
External links
www.pituitary.org — The Pituitary Network Association
v
t
e
Anatomy of the endocrine system
Pituitary gland
Anterior
Pars intermedia
Pars tuberalis
Pars distalis
Acidophil cell
Somatotropic cell
Prolactin cell
Somatomammotrophic cell
Basophil cell
Corticotropic cell
Gonadotropic cell
Thyrotropic cell
Chromophobe cell
Posterior
Pars nervosa
Median eminence
Stalk
Pituicyte
Herring bodies
Thyroid
Follicular cell
Parafollicular cell
Parathyroid gland
Chief cell
Oxyphil cell
Adrenal gland
Cortex
Zona glomerulosa
Zona fasciculata
Zona reticularis
Medulla
Chromaffin cell
Gonads
Testicle
Leydig cell
Sertoli cell
Ovary
Theca interna
Granulosa cell
Corpus luteum
Islets of pancreas
Alpha cell
Beta cell
PP cell
Delta cell
Epsilon cell
Pineal gland
Pinealocyte
Corpora arenacea
Other
Enteroendocrine cell
Paraganglia
Organ of Zuckerkandl
Placenta
Development
List of human endocrine organs and actions
v
t
e
Anatomy of the diencephalon of the human brain
Epithalamus
Surface
Pineal gland
Habenula
Habenular trigone
Habenular commissure
Grey matter
Pretectal area
Habenular nuclei
Subcommissural organ
Thalamus
Surface
Stria medullaris of thalamus
Thalamic reticular nucleus
Taenia thalami
Grey matter/ nuclei
paired: AN
Ventral
VA/VL
VP/VPM/VPL
Lateral
LD
LP
Pulvinar nuclei
Metathalamus
MG
LG
P cell
M cell
K cell
midline: MD
Intralaminar
Centromedian
Midline nuclear group
Interthalamic adhesion
White matter
Mammillothalamic tract
Pallidothalamic tracts
Ansa lenticularis
Lenticular fasciculus
Thalamic fasciculus
PCML
Medial lemniscus
Trigeminal lemniscus
Spinothalamic tract
Lateral lemniscus
Dentatothalamic tract
Acoustic radiation
Optic radiation
Subthalamic fasciculus
Anterior trigeminothalamic tract
Medullary laminae
Hypothalamus
Surface
Median eminence/Tuber cinereum
Mammillary body
Infundibulum
Grey matter
Autonomic zones
Anterior (parasympathetic/heat loss)
Posterior (sympathetic/heat conservation)
Endocrine
posterior pituitary: Paraventricular
Magnocellular neurosecretory cell
Parvocellular neurosecretory cell
Supraoptic
oxytocin/vasopressin
other: Arcuate (dopamine/GHRH)
Preoptic (GnRH)
Suprachiasmatic (melatonin)
Emotion
Lateral
Ventromedial
Dorsomedial
White matter
afferent
Medial forebrain bundle
Retinohypothalamic tract
efferent
Mammillothalamic tract
Stria terminalis
Dorsal longitudinal fasciculus
Pituitary
Posterior is diencephalon, but anterior is glandular
Subthalamus
Subthalamic nucleus
Zona incerta
Nuclei campi perizonalis (Fields of Forel)
Authority control
GND: 4171584-6
TA98: A11.1.00.006
UpToDate Contents
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Lymphocytic Hypophysitis with a Long Latent Period from Onset of Central Diabetes Insipidus to Development of Pituitary Enlargement
Akahori Hiroshi,Sugimoto Tatsuho
Internal Medicine 49(15), 1565-1571, 2010
… Initial pituitary MRI imaging was normal, except for loss of the "bright spot" of the posterior lobe. … Two years later, pituitarygland enlargement with panhypopituitarism was detected. … Eight months after commencing a replacement dose of corticosteroid, the pituitary enlargement was reduced in size. …
(pĭ-t 'ĭ-těr'ē) A gland at the base of the brain in vertebrate animals that is divided into two regions, anterior and posterior, each of which secretes important hormones. The anterior portion, whose secretions are directly controlled by ...
Anterior Pituitary Although the hypothalamus does not produce the hormones of the anterior pituitary as in the posterior pituitary, it plays an important role in their production. Releasing ...