Hypophysis Cerebri

(also known as pituitary gland)
Introduction
• It is a gland under control of hypothalamus, and is
suspended from the floor of the third ventricle by
infundibulum.
• It lie at the base of the skull at a depression known as sella
turcica (hypophyseal fossa) of the sphenoid bone.
• Transversely it is 12 mm. Antero-posteriorly it is 8 mm.
• Its wieght is about 500 mg.
• It is roofed by diaphragma sellae.
• The gland is not surrounded by cerebrospinal fluid
Parts of the hypophysis cerebri
 Hypophysis cerebri or pituitary gland consists of two parts
that are distinct from each other in development, structure
and function. These are
a. Adenohypophysis or Anterior lobe
b. Neurohypophysis or posterior lobe
Gross Anatomy of Anterior lobe
• This part of pituitary gland is highly cellular and occasionally
presents an intra glandular cleft
• The parts behind the cleft is known as pars intermedia (since
this is the part between the anterior and posterior lobe).
• The part in front of the lobe is known as pars anterior
• The part that extends upwards and is continuous with the
infundibular stem is known as pars tuberalis.
• SO THE ADENOHYPOPHYSIS OR THE ANTERIOR LOBE
PRESENTS THREE PARTS.
Gross Anatomy of posterior lobe
• It is also continuous with infndibulum above and extends
downward through the floor of the third ventricle and
enters the hypophyseal fossa through diaphragma sellae.
• Its parts are :
a. The median eminence of tuber cinerum (continuous with
infundibular stem)
b. Infundibular stem and
c. Pars nervosa
• Infundibular stem has the anterior covering of the pars
tuberalis.
Relations of the Gland
• On each side- cavernous sinus
• In front- Anterior intercavernous sinus
• Behind- Posterior intercavernous sinus.
• Above-Floor of the third ventricle speprated from the gland
by diaphragma sellae. Also optic chiasma
• Below-Sphenoidal air sinus seperated by a plate of bone.
Micro Anatomy of Anterior lobe
Generalized Microanatomy
 The parenchyma of the anterior lobe consists of epithelial
cells that are (supported by fibres and) permeated by
sinusiods and fenestrated capillary plexus.
 The cells can be classified as chromophobes and
chromophills.
 Chromophobes are non granular due to the fact that either
they have secreted most of their hormones or that they are
the precursors of the Chromophil cells.
 Chromophils are subdivided into acidophil and basophil.
Microanatomy of Acidophils
• Acidophils consists of two types of cells namely orangeophils
and carminophils.
• Orangeophils secrete GH or STH i.e. the growth hormones

hence the cells are also known as somatotrophs.
• Carminophils secrete LTH (lactogenic hormone), and

therefor its cells are also known as mammotrophs.
Microanatomy of Basophlis
• Depending the staining results by aldehyde fuchsin, the cells
are of two types: Beta basophils and delta basophils.
• Beta basophils secrete TSH
• Delta basophils secrete FSH, LH in female and ICSH in male.

These hormones are also known as gonadotrophs.
• MSH is secreted by the Pars intermedia which also secrete

ACTH. ACTH is also secreted by follicle cells that are
arranged around a central mass of glycoproteins.
Microanatomy of posterior lobe
• It consists of unmyelinated nerve fibres, fenestrated blood
capillary plexus and special neuroglial cells called pituicytes.
• These unmylinated nerve fibres have knob-like terminals

called Herring bodies.
• Herring bodies contain secretory vesicles that abut on the

surface of blood capillaries.
Nerve supply of Pituitary Gland
 Pituitary Gland is supplied by the Hypothalamo Hypophyseal
Tract that starts from the supraoptic and paraventricular
nuclei. These nerve fibres enter the posterior lobe through
infundibular stem
 Starting from the hypothalamus, these unmyelineted
neurons reach the neurohypophysis and and ends in Herring
bodies that contains secretory vessels.
 Supraoptic nuclei secrete Vasopressin and paraventricular
nuclei secrete oxytocin.
Blood Supply in general
From Superior Artery….
To the anterior Lobe…
• The anterior lobe is supplied with the superior hypophyseal
artery.
• The artery enters pars tuberalis.
• The artery breaks up into capillary tufts in the median
eminence and infundibular stem.
• The blood is then forwarded onto the long and intermediate
portal vessels to the secondary capillary and sinusiodal
plexus.
• Finally the blood is drained into cavernous and
intercavernous sinuses.
To the Posterior lobe…
• The posterior lobe is suppled with inferior hypophyseal
artery.
• It divides into capillary beads in the lobe
• Finally drains into cavernous and intercavernous sinuses
• Short portal veins connect the capillary beads of the anterior
and posterior lobe. Here the blood flow is probably antero-
posterior.
There is also…..
• The tubero-infundibular duct from the arcuate nucleus of
Hypophysiotropic area also conveys 7 hormones.
• The hormones are conveyed to the fenestrated upper

(radicles of) capillary tufts in the median eminence and
infundibular stem.

Hypophysis Cerebri

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(also known as pituitary gland)

• Orangeophils secrete GH or STH i.e. the growth hormones

• Carminophils secrete LTH (lactogenic hormone), and

• Beta basophils secrete TSH

• Delta basophils secrete FSH, LH in female and ICSH in male.

• MSH is secreted by the Pars intermedia which also secrete

• These unmylinated nerve fibres have knob-like terminals

• Herring bodies contain secretory vesicles that abut on the

• The hormones are conveyed to the fenestrated upper

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