Endocrine System Quiz

Pituitary Gland (Hypophysis Cerebri)

• Located in the hypophyseal fossa of the sphenoid bone
• Attached to the undersurface of the brain by the stalk-like infundibulum
• Pierces the diaphragma sellae to reach the gland
• Well-protected by its location
• Often referred to as the master endocrine gland due to its influence on many other endocrine glands
• Vital to life

Structure

• Composed of two lobes: anterior lobe (adenohypophysis) and posterior lobe (neurohypophysis)
• Anterior lobe subdivided into pars anterior (pars distalis) and pars intermedia
• Pars tuberalis extends up along the anterior and lateral surfaces of the pituitary stalk

Relations

• Anterior: Sphenoid sinus
• Posterior: Dorsum sellae, basilar artery, and pons
• Superior: Diaphragma sellae with a central aperture allowing passage of the infundibulum
• Inferior: Body of the sphenoid with sphenoid air sinuses
• Lateral: Cavernous sinus and its contents

Blood Supply

• Supplied by the superior and inferior hypophyseal arteries, branches of the internal carotid artery
• Veins drain into the intercavernous sinuses

Functions

• Influences the activities of many other endocrine glands
• Controlled by the hypothalamus, which is modified by information from the central nervous system and plasma levels of electrolytes and hormones

Embryology

• Develops from two sources: Rathke's pouch and the infundibulum
• Rathke's pouch grows superiorly from the roof of the stomodeum
• Infundibulum grows inferiorly from the floor of the diencephalon of the brain
• Cells of the anterior wall of the vesicle form the pars anterior of the pituitary
• Cells of the posterior wall form the pars intermedia

Pineal Gland

• Small cone-shaped body projecting posteriorly from the posterior end of the roof of the third ventricle of the brain
• Composed of groups of cells, the pinealocytes

This quiz covers the anatomy and physiology of the endocrine system, including the pituitary gland, thyroid gland, and parathyroid glands.