1. EMBRYOLOGY AND ANATOMY

• Three distinct parts of the pituitary are the:

  Anterior pituitary (adenohypophysis)

  Intermediate lobe (pars intermedialis)

  Posterior pituitary (neurohypophysis)
• The Intermediate lobe is poorly developed in humans and has little functional capacity other than to confuse radiologists by forming nonfunctional, benign, cystic, enlargements of the pituitary.
• The Posterior pituitary, which arises from diencephalon, is responsible for the storage and release of oxytocin and vasopressin.
• Vasopressin is also called antidiuretic hormone (ADH)
• The Anterior pituitary, the largest portion of the gland, originates from Rathke's pouch.
• Rathke's pouch -an evaginationof buccal ectoderm that progressively extends upward and is eventually enveloped by the sphenoid bone.
• The creation of the median eminence (inferior portion of the hypothalamus), and the pituitary stalk is the othe critical event in the formation of the hypothalamic-hypophyseal unit.
• How many weeks does the pituitary function can be detected?

  7th and 9th weeks of gestation
• The ultimate determination of ANTERIOR PITUITARY CELLS types is dependent on the spatial relationships of progenitor cell types and an integrated flow of transcription factors that ultimately form:

  1. Lactotrophs (prolactin-secreting cells)
  2. Somatotrophs (growth hormone (GH)-screening cells)
  3. Thyrotrophs (TSH-secreting cells)
  4. Corticotrophs (ACTH-secreting cells)
  5. Gonadotrophs (LH and FSH-secreting cells)
• The pituitary resides in a pocket of the sphenoid (the sella turcica, meaning "Turkish saddle") and is surrounded by dura mater.
• The reflection of dura that separates the superior portion of the pituitary from the hypothalamus, the diaphragm sella, is penetrated by the infundibulum, or pituitary stalk, that connects the adenohypophysis to the media eminence and hypothalamus.
• The pituitary stalk contains both neural and vascular structures that terminate in the hypophysis.
• The Posterior pituitary is connected to the ____ (two way)

  supraoptic and paraventicular hypothalamic nuclei.
• Where does vasopressin and oxytocin production occur?

  Paraventicular hypothalamic nuclei
• What three(3) tracts that passes through the stalk?

  Neurosecretory tracts

  Supraopticohypophyseal tracts

  Tuberohypophyseal tracts
• How many percent of blood supply does Anterior pituitary and other factorsreceives?

  80% to 90%
• 80%-90% of blood supply gives to Anterior pituitary via hypothalamic-hypophyseal portal system (also contain in the stalk)
• The primary plexus of this portal system is located in the median eminence and is composed of capillaries lacking a blood-brain barrier (fenestrated capillaries), where the Hypothalamic nuclei that modulate pituitary function terminate their axons.
• The long portal vessels connect the primary plexus to the Anterior pituitary and serve as a conduct for these hypothalamic-hypophysiotropic hormones.
• Anatomic relationship of pituitary and hypothalamus.

  
• What are the two other critical event in the formation of the hypothalamic-hypophyseal unit?

  median eminence and pituitary stalk