01-Anatomy of pituitary gland 1.ppt - ANATOMY OF THE...

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Unformatted text preview: ANATOMY OF THE PITUITARY GLAND OBJECTIVES At the end of the lecture, students should be able to: Describe the position of the pituitary gland. List the structures related to the pituitary gland. Differentiate between the lobes of the gland. gland Describe the blood supply of pituitary gland & the hypophyseal portal system. PITUITARY GLAND (HYPOPHYSIS CEREBRI) It is referred to as the master of endocrine glands. glands It is a small oval structure 1 cm in diameter. PITUITARY GLAND X-RAY SKULL: LATERAL VIEW SAGITTAL SECTION OF HEAD & NECK Pituitary gland Hypophyseal fossa Sphenoidal air sinus POSITION It lies in the middle cranial fossa It is well protected in sella turcica (hypophyseal fossa) of body of sphenoid Sella turcica Optic chiasma Mamillary body Body of sphenoi it lies between optic chiasma (anteriorly) & mamillary bodies (posteriorly). 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. IMPORTANT RELATIONS SUPERIOR: Diaphragma sellae INFERIOR: Sphenoidal air sinuses LATERAL: Cavernous sinuses SUBDIVISIONS OF PITUITARY GLAND Hypothalamo-hypophyseal tract The gland is subdivided into: 1) Anterior lobe (Adenohypophysis): it is the True gland, Secretes hormones 2) Posterior lobe (Neurohypophysis): connected to hypothalamus through hypothalamo-hypophyseal tract, tract Stores hormones secreted by hypothalamic nuclei BLOOD SUPPLY OF PITUITARY GLAND ARTERIES: Superior & inferior hypophyseal arteries (branches of internal carotid artery) VEINS: Hypophyseal veins drain into Cavernous Sinuses. DISTRIBUTION OF ARTERIES a hypothalamohypophseal portal vessel 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). Inferior hypophyseal: supplies posterior lobe of pituitary gland. ANTERIOR LOBE Hormone-releasing & inhibiting factors produced by hypothalamus use Hypophyseal Portal System of vessels to reach the Anterior lobe of pituitary gland POSTERIOR LOBE The neurohypophysis receives a nerve supply from some of the hypothalamic nuclei (supraoptic & paraventricular) The axons of these nuclei convey their neurosecretion to the Posterior lobe of pituitary gland through HypothalamoHypophyseal tract from where it passes into the blood stream. THANK U ...
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