Hypophysis

Hypophysis

1. Location and structure

   • Oval Pea sized
   • Connects to hypothalamus by the infundibulum
   • Situated in the middle cranial fossa in the sella turcica of the sphenoid bone
   • 2 lobes
     • Anterior lobe/ Adenohypophysis
       • Produce hormones: GH, TSH, ACTH, PRL, FSH
     • Posterior lobe/ Neurohypophysis
       • Releases neurohormones that it receives from hypothalamus: Oxytocin and ADH

2. Embryology

   • Anterior Lobe
     • Develops from an ectodermal outpocketing from the roof of the mouth
   • Posterior lobe
     • Develops from a downwards extension of the hypothalamus via a nerve bundle called the hypothalmic- hypophyseal tract, runs through infundibulum

3. Blood supply

   • Anterior lobe
     • Supplied by superior hypophyseal arteries
     • Venous drainage via anterior hypophyseal veins
   • Posterior Lobe
     • Supplied by inferior hypophyseal arteries
     • Venous drainage via posterior hypophyseal veins to the cavernous vein