Dr. fahad albadr

At the end of the lecture, students should At the end of the lecture, students should be able to:be able to:

Describe the positionposition of the pituitary gland.

List the structures relatedthe structures related to the pituitary gland.

Differentiate between the lobes of the the lobes of the glandgland.

It is referred to as the master of endocrine glandsmaster of endocrine glands.It is a small oval structure 1 cm in diameter.

X-RAY SKULL: LATERAL VIEW

SAGITTAL SECTION OF HEAD & NECK

Hypophyseal fossa

Sphenoidal air sinus

Pituitarygland

It lies in the middle cranial fossa

It is well protected in sella turcica (hypophyseal fossa) of body of sphenoid

Sella turcica

POSITION

it lies between optic chiasma optic chiasma (anteriorly) & mamillary bodies mamillary bodies (posteriorly).

Mamillary body

Optic chiasma

Body of sphenoid

A fold of dura mater (Diaphragma sellae) covers the pituitary gland & has an opening for passage of infundibulum (pituitary

stalk) connecting the gland to hypothalamus.

SUPERIORSUPERIOR: : Diaphragma sellaeINFERIOR: INFERIOR: Sphenoidal air sinuses

LATERAL:LATERAL: Cavernous sinuses

The gland is subdivided into:

1) Anterior lobe (Adenohypophysis): it is the it is the True gland, Secretes hormones

2) Posterior lobe (Neurohypophysis): connected to hypothalamus through hypothalamo-hypophyseal tracthypothalamo-hypophyseal tract, Stores hormones secreted by hypothalamic nuclei

Hypothalamo-hypophyseal tract

ARTERIES: ARTERIES: Superior & inferior hypophyseal arteries (branches of internal carotid artery)

VEINS:VEINS: Hypophyseal veins drain into Cavernous Sinuses.

Superior hypophyseal: Superior hypophyseal: supplies infundibulum & forms a capillary network from which vessels pass downward & form sinusoids into the anterior lobe of pituitary gland (hypophyseal portal system).(hypophyseal portal system).Inferior hypophysealInferior hypophyseal: : supplies posterior lobe of pituitary gland.

a hypothalamo-hypophseal portal vessel

Hormone-releasing & Hormone-releasing & inhibiting factors inhibiting factors produced by hypothalamus use Hypophyseal Portal System of vessels to reach the Anterior lobe of pituitary gland

ANTERIOR LOBE

The neurohypophysis The neurohypophysis receives a nerve supply from receives a nerve supply from

some of the hypothalamic some of the hypothalamic nuclei (nuclei (supraoptic supraoptic & &

paraventricularparaventricular) ) The axons of these nuclei The axons of these nuclei

convey convey their neurosecretion neurosecretion to the Posterior lobe of pituitary gland through Hypothalamo-

Hypophyseal tract from where it passes into the blood

stream.

POSTERIOR LOBE

The gland is composed of two parts:Anterior lobe (adeno hypophysis)Posterior lobe (neuro hypophysis)

Normal size:Weight: 0.5gHeight: 4-12 mmAnterior posterior: 5-16 mm

Hormonal dysfunctionCushing syndromeGrowth abnormalities e.g. Growth hormone deficiency, acromegaly

Visual abnormalitiesheadache

What is best modality to image the pituitary gland ?

A. X rayB. CT scanC. MRID. USE. Nuclear medicine

What is best modality to image the pituitary gland ?

A. X rayB. CT scan

C.MRI D. USE. Nuclear medicine

CT scan MRI

CT scan MRI

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1-Optic sulcus2- Anterior clinoid process3-Floor of sella turcia (Pituitary fossa)4- Posterior clinoid process 5- Dorsum sella6- Sphenoid sinus

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1 -pituitary gland

2 -sphenoid sinus

3 -optic chiasm4 -

hypothalamus5 -pituitary

stalk6 -claivus

NORMAL PITUITARY ADENOMA

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Pituitary gland

Optic chiasm

Pituitary stalk

Carotid artery

Cavernous sinus Sphenoid

sinus