The pituitary stalk, also known as the infundibular stalk, infundibulum, or Fenderson's funnel, is the connection between the
hypothalamus
The hypothalamus (: hypothalami; ) is a small part of the vertebrate brain that contains a number of nucleus (neuroanatomy), nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrin ...
and the
posterior pituitary
The posterior pituitary (or neurohypophysis) is the posterior lobe of the pituitary gland which is part of the endocrine system. Unlike the anterior pituitary, the posterior pituitary is not glandular, but largely a collection of axonal projec ...
, the posterior lobe of the
pituitary gland
The pituitary gland or hypophysis is an endocrine gland in vertebrates. In humans, the pituitary gland is located at the base of the human brain, brain, protruding off the bottom of the hypothalamus. The pituitary gland and the hypothalamus contr ...
. The floor of the
third ventricle
The third ventricle is one of the four connected cerebral ventricles of the ventricular system within the mammalian brain. It is a slit-like cavity formed in the diencephalon between the two thalami, in the midline between the right and lef ...
is prolonged downward as a funnel-shaped recess—the infundibular recess—into the infundibulum, where the apex of the pituitary is attached.
[''Grey's Anatomy'']
It passes through the
dura mater of the
diaphragma sellae
The diaphragma sellae or sellar diaphragm is a small, circular sheet of dura mater forming an (incomplete) roof over the sella turcica and covering the pituitary gland lodged therein. The diaphragma sellae forms a central opening to accommodate the ...
as it carries
axon
An axon (from Greek ἄξων ''áxōn'', axis) or nerve fiber (or nerve fibre: see American and British English spelling differences#-re, -er, spelling differences) is a long, slender cellular extensions, projection of a nerve cell, or neuron, ...
s from the
magnocellular neurosecretory cell
Magnocellular neurosecretory cells are large neuroendocrine cells within the supraoptic nucleus and paraventricular nucleus of the hypothalamus. They are also found in smaller numbers in accessory cell groups between these two nuclei, the larges ...
s of the hypothalamus down to the posterior pituitary where they release their
neurohypophysial hormone
The neurohypophysial hormones form a family of structurally and functionally related peptide hormones. Their representatives in humans are oxytocin and vasopressin. They are named after the location of their release into the blood, the neurohy ...
s,
oxytocin
Oxytocin is a peptide hormone and neuropeptide normally produced in the hypothalamus and released by the posterior pituitary. Present in animals since early stages of evolution, in humans it plays roles in behavior that include Human bonding, ...
and
vasopressin
Mammalian vasopressin, also called antidiuretic hormone (ADH), arginine vasopressin (AVP) or argipressin, is a hormone synthesized from the ''AVP'' gene as a peptide prohormone in neurons in the hypothalamus, and is converted to AVP. It ...
, into the
blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells.
Blood is com ...
.
Damage to the pituitary stalk blocks the release of
antidiuretic hormone
Mammalian vasopressin, also called antidiuretic hormone (ADH), arginine vasopressin (AVP) or argipressin, is a hormone synthesized from the ''AVP'' gene as a peptide prohormone in neurons in the hypothalamus, and is converted to AVP. It ...
, resulting in
polydipsia
Polydipsia is excessive thirst or excess drinking.Porth, C. M. (1990). ''Pathophysiology: Concepts of altered health states''. Philadelphia: J.B. Lippincott Company. The word derives , which is derived . Polydipsia is a nonspecific symptom in v ...
(excessive water intake) and
polyuria
Polyuria () is excessive or an abnormally large production or Frequent urination, passage of urine (greater than 2.5 L or 3 L over 24 hours in adults). Increased production and passage of urine may also be termed as diuresis. Polyuria often appe ...
(excessive urination,
central diabetes insipidus
Central diabetes insipidus, recently renamed arginine vasopressin deficiency (AVP-D), is a form of diabetes insipidus that is due to a lack of vasopressin (ADH) production in the brain. Vasopressin acts to increase the blood volume, volume of bl ...
).
The diameter of the pituitary stalk at the level of optic chiasm is 3.3 mm, and at the pituitary gland insertion site is measured at 1.9 mm.
See also
*
Pituitary stalk interruption syndrome
Pituitary stalk interruption syndrome (PSIS) is a congenital disorder characterised by the triad of an absent or exceedingly thin pituitary stalk, an ectopic or absent posterior pituitary and/or absent or hypoplastic anterior pituitary.
Present ...
Additional images
File:Gray1180.png, Sagittal
The sagittal plane (; also known as the longitudinal plane) is an anatomical plane that divides the body into right and left sections. It is perpendicular to the transverse plane, transverse and coronal plane, coronal planes. The plane may be in ...
section of the pituitary gland, showing the infundibulum
References
{{Authority control
Endocrine system
Hypothalamus