PITUITARY gland anatomy and physiology with clinical presentations of disturbances.pptx

pituitary gland is the maestro of the different glands of the body to preserve the body in a good health.

1. Let’s get started

2. The pituitary gland is the master gland of the body. The sella turcica is approximately 0.6 cm high, 1 cm wide, and 1.3 cm deep.

3. Diaphragma Sellae It is a double layer of dura that separates the pituitary from the brain. This dural layer may be incomplete, So : Tumors erupt easily into the suprasellar space. Increases the chance of post-op. CSF rhinorrhea.

4. Blood Supply The anterior pituitary is supplied by the superior hypophyseal artery , which arises just proximal to the entry of the ICA into the cavernous sinus.

5. Blood Supply The posterior pituitary is supplied by the inferior hypophyseal artery , which is a branch of the meningohypophyseal trunk of the ICA in the cavernous sinus.

6. Branches of these vessels form a capillary plexus in the infundibulum Axons from hypothalamic neurons terminate on these capillaries, allowing release of pituitary hormone regulatory factors.

7. Function of the normal pituitary gland depends on: Integrity of the hypothalamus, Portal circulation, and Pituitary stalk. Which is known as HYPOTHALAMIC-PITUITARY AXIS

8. The human pituitary gland is consisting of two basic anatomic components: Adenohypophysis Neurohypophysis Each differing in embryological origin, structure, function, and the types of pathological processes that can arise therein

9. It normally enlarges during pregnancy, increasing in size by 50% or more. The gland also shows significant variation in size and configuration across the phases of the menstrual cycle.

10. Pituitary Development: The Tale of Two Glands

11. Pituitary- MRI

12. Pituitary- Vascular Supply

13. Hypothalamus Function

14. Regulation of TSH TRH secreted from paraventricular nucleus, 3 amino acids long TRH stimulates secretion of TSH, a glycoprotein TSH stimulates thyroid gland to produce thyroid hormones Entire process is controlled by a classic negative feedback loop

15. Regulation of LH/FSH GnRH aka LHRH is a ten amino acid peptide created in the preoptic hypothalamus GnRH causes pituitary to release LH and FSH LH stimulates secretion of testosterone and estrogen/progesterone FSH stimulates maturation of ovarian follicles and sperm production

16. Regulation of ACTH CRH secreted from paraventricular nucleus CRH stimulates pituitary release of ACTH ACTH stimulates adrenal glands to produce glucocorticoids such as cortisol

17. Regulation of Growth Hormone GHRH and somatostatin (SS) produced in the arcuate nucleus of hypothalamus GHRH stimulates release of pituitary GH SS inhibits release of GH GH has multiple effective sites including fat cells, myocytes, and bone

18. Regulation of Prolactin Dopamine created in the arcuate nucleus Dopamine inhibits the secretion of prolactin from the pituitary Prolactin induces mammary gland growth and milk production

19. Pars Nervosa- Hormones Herring Bodies Dilated bulge of axons containing clusters of neurosecretory granules Oxytocin Antidiuretic Hormone (ADH)

20. ADH and Oxytocin ADH binds to distal tubule in kidney to promote water reabsorption 9 amino acid peptide released in response to plasma osmolality Oxytocin responsible for milk ejection and uterine contraction with unknown function in males 9 amino acid peptide release in response to nipple stimulation

21. Hypothalamus-Pituitary

22. Histology Recent histological studies based on molecular biological techniques recognize five cell types Somatotrophs, Lactotrophs Gonadotrophs, Corticotrophs Thyrotrophs