DEVELOPMENT &

STRUCTURE OF THE

PITUITARY GLAND

DR TATHEER ZAHRA

ASSISTANT PROFESSOR ANATOMY

PITUITARY GLAND/

HYPOPHYSIS CEREBRINomenclature

Master gland

Size

Shape

Weight

Capsule

Location

Relations

ANTERIOR

• Duramater

• Sphenoidal air sinuses

POSTERIOR

• Duramater

• Dorsum sallae

• Sphenoidal air sinuses

• Basilar artery

• Pons

SUPERIOR

• Diaphragmasellae

• Optic chiasma

• 3rd ventricle

INFERIOR

• Dural floor of the fossa

• Intercavernoussinus

• Body of sphenoid

• Sphenoidal air sinuses

LATERAL

• Duramater

• Cavernous sinus

NEUROVASCULAR SUPPLY

Several superior hypophyseal

arteries Inferior hypophyseal artery

Primary capillary plexus

Secondary capillary plexus

Venous drainage

Superior & inferior

hypophyseal veins

Cavernous sinus

Nerve supply ~ Postsynaptic fibers

of ANS (Vasomotor to Ant. Lobe),

Hypothalamic nuclei (Post. Lobe)

Fenestrated capillaries

Sinusoidal

capillaries

CONNECTIONS OF THE HYPOTHALAMUS

WITH PITUITARY GLAND

HYPOTHALAMO-HYPOPHYSEAL

TRACT HYPOPHYSEAL PORTAL SYSTEM

DEVELOPMENT OF THE

PITUITARY GLAND

ADENOHYPOPHYSIS

• ECTODERM OF THE STOMODEUM OROPHARYNX/ RATHKE’S POUCH

NEUROHYPOPHYSIS

• NEUROECTODERM OF THE FLOOR OF THE 3RD VENTRICLE/ DIENCEPHALON

3RD WEEK

5TH WEEK

6TH WEEK

HYPOPHYSEAL DEFECTS

Pharyngeal Hypophysis

Craniopharyngiomas

Basipharyngeal Canal

Microadenoma (< 1cm in diameter)

Macroadenoma (> 1cm in diameter)

Mechanical effects of tumors ~ Neurological defects, Bitemporal hemianopia (Tunnel

vision), Headache, Epistaxis, CSF Rhinorrhea, Hydrocephalus etc.

Treatment options ~ Medication, Surgery, Radiotherapy, Combination

SURGICAL APPROACHESTRANS-SPHENOIDAL APPROACH (via orbit or nasal septum)

CRANIOTOMY FOR SUB-FRONTAL APPROACH

CRANIOTOMY FOR TRANS-CAVERNOUS APPROACH

LE FORT MAXILLOTOMY

INTRAOPERATIVE MRI (IMRI)

TRANS-SPHENOIDAL

APPROACH

Through orbit: Via ethmoidal air cells after raising the periosteum from the medial wall of the orbit

Through nasal septum:

*By elevating the nasal mucosa from the nasal septum & removing the septum (the nasal cavity itself is not entered)

*Maxilla-premaxilla (Cottle) approach by preserving the caudal end of the nasal septum & the anterior nasal spine

CRANIOTOMY FOR

SUB-FRONTAL APPROACH

CRANIOTOMY FOR

TRANS-CAVERNOUS

APPROACH

Trans-cavernous Approach

LE FORT MAXILLOTOMY

INTRAOPERATIVE

MRI (IMRI)

Pre operative:

Polytomograms of sella

& sphenoid sinus

Bilateral carotid

angiography

CT scan

Pneumoencephalography

Intra-operative:

Operating microscope

Intra-operative x-ray

control with image

intensifier

ORGANIZATIONADENOHYPOPHYSIS

(Glandular part)

Pars tuberalis

Pars distalis-pars

anterior

Pars intermedia

NEUROHYPOPHYSIS

(Nervous part)

Pars nervosa

Infundibulum

(Infundibular stem &

Median eminence)

ADENOHYPOPHYSIS

PARS DISTALIS

PARS TUBERALIS

PARS INTERMEDIA

PARS DISTALIS

75% of the mass of the hypophysis

Highly vascular

Common stains allow recognition of 3 cell

types

Folliculostellate cells

Chromophobes ~ 50 %

2 types of chromophils

Acidophils ~ 35-40 %

Basophils ~ 10-15 %

ACIDOPHILS

SOMATOTROPES/

GH CELLSMAMMOTROPES/

PRL CELLS

50% 15-20%

REGULATION OF SECRETIONSOMATOTROPES/

GH CELLS

MAMMOTROPES/ PRL

CELLS

PROLACTIN

TRH

VIP

DOPAMINE

HYPOTHALAMUS

GHRH

SOMATOTROPES

GH

BASOPHILS

GONADOTROPES/

FSH & LH CELLS

THYROTROPES/

TSH CELLS

CORTICOTROPES/

ACTH CELLS

10%

5%

15-20%

Pars distalis: Crystal scarlet, aniline blue

& Martius yellow

REGULATION OF SECRETION

GONADOTROPES/

FSH & LH CELLS

THYROTROPES

/ TSH CELLS

HYPOTHALAMUS

GnRH

GONADOTOTROPES

FSH & LH

CORTICOTROPES

/ ACTH CELLS

HYPOTHALAMUS

TRH

THYROTROPES

TSH

HYPOTHALAMUS

CRH

CORTICOTROPES

POMC

ACTH

PARS TUBERALIS

Folliculostellate

cells

Basophils

Corticotropes

Gonadotropes

PARS INTERMEDIA

Folliculostellate

cells

Chromophobes

Basophils

Corticotropes

Black arrow -

Rathke's Pouch

Blue arrow –

Adenohypophysis

Red arrow –

Neurohypophysis

SUMMARY OF SECRETORY CELLS OF ADENOHYPOPHYSIS

PIHPRH

+ -

SUMMARY OF REGULATION OF SECRETION OF ADENOHYPOPHYSIS

NEOROHYPOPHYSIS

NEUROHYPOPHYSIS

INFUNDIBULUM/ NEURAL STALK

MEDIAL EMINENCE STEM

PARS NERVOSA

INFUNDIBULUM/ PITUITARY

STALK

PARS NERVOSA

HERRING BODIES

E/M of Herring bodies of rat posterior lobe

HORMONES OF THE PARS

NERVOSA

VASSOPRESSIN BY SUPRAOPTIC

NUCLEUS

OXYTOCIN BY PARAVENTRICULAR

NUCLEUS

CONTROL OF SECRETION

FACTORS AFFECTING

SECRETION:

a. Osmotic stimuli

b. Volume effect

c. Other stimuli:

Pain

Nausea

Surgical stress

Drugs:Morphine

Nicotine

Barbiturate

Alcohol

Opiate antagonist

Hypertonicity Hypovolemia

Osmoreceptors Baroreceptors

Hypothalamus

Thirst

REFERENCESThe Developing Human, Clinically Oriented Embryology, By KEITH L.

MOORE - Latest Edition

LANGMAN’S Embryology, By T.W.SADLER - Latest Edition

LAST’S Anatomy Regional & Applied, By CHUMMY S.

SINNATAMBY - Latest Edition

Clinically Oriented Anatomy, By KEITH L. MOORE - Latest Edition

Clinical Anatomy By Regions, By RICHARD S. SNELL - Latest Edition

Basic Histology Text & Atlas, By LUIZ CARLOS JUNQUEIRA &

JOSé CARNEIRO - Latest Edition