Objectives • Discus the position of the pituitary. • Discus the relations of the pituitary. • Discus the blood supply of the pituitary. • Discus the functions of the pituitary.
The pituitary gland • The pituitary gland is a small, oval structure attached to the undersurface of the brain by the infundibulum. • Located in the sellaturcicaof the sphenoid bone. • Divided into an anterior lobe, or adenohypophysis, and a posterior lobe, or neurohypophysis.
The anterior lobe is subdivided into the pars anterior (pars distalis) and the pars intermedia. • The pars tuberalisis a projection from the pars anterior.
PITUITARY GLAND X-RAY SKULL: LATERAL VIEW SAGITTAL SECTION OF HEAD & NECK Pituitary gland Hypophyseal fossa Sphenoidal air sinus
PITUITARY GLAND(HYPOPHYSIS CEREBRI) It is referred to as the master of endocrine glands. It is a small oval structure 1 cm in diameter.
Relations: • Anteriorly: The sphenoid sinus. • Posteriorly: The dorsum sellae, the basilar artery, and the pons. • Superiorly: The diaphragmasellae, which has a central aperture that allows the passage of the infundibulum. The diaphragmasellae separates the anterior lobe from the optic chiasma.
Inferiorly: The body of the sphenoid, with its sphenoid air sinuses. • Laterally: The cavernous sinus and its contents.
Blood Supply: • The arteries are derived from the superior and inferior hypophyseal arteries, branches of the internal carotid artery. The veins drain into the intercavernous sinuses.
Functions of the Pituitary Gland: • The pituitary gland influences the activities of many other endocrine glands. The pituitary gland is itself controlled by the hypothalamus and the activities of the hypothalamus are modified by information received along numerous nervous afferent pathways from different parts of the central nervous system and by the plasma levels of the circulating electrolytes and hormones