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DR NILESH KATE
MBBS,MDASSOCIATE PROF
DEPT. OF PHYSIOLOGY
PITUITARY GLAND
OBJECTIVES. Introduction and functional anatomy. Anterior pituitary hormones
Growth hormones Applied aspects.
Monday, May 1, 2023
INTRODUCTION AND FUNCTIONAL ANATOMY.
Hypothalamo-pituitary unit– important component of endocrine system
Controls – Growth, Lactation, Fluid balance, thyroid, adrenals & gonads.
Monday, May 1, 2023
GROSS ANATOMY Pituitary Gland –
hypophysis cerebri Wt – 0.5 gm Location –
hypophyseal fossa Suspended by pituitary
stalk which connects it to hypothalamus.
Monday, May 1, 2023
DEVELOPMENT. Anterior pituitary –
Ectodermal origin. From Rathke’s pouch Upward out pouching from
roof of primitive oral cavity.
Posterior pituitary. Lowered out pouching
From Neuroectodermal tissues of central hypothalamus.
Monday, May 1, 2023
PARTS OF PITUITARY GLAND. Adenohypophysis Neurohypophysis. Pituitary stalk.
Monday, May 1, 2023
ADENOHYPOPHYSIS Forms 80% 3 parts Pars Distalis – main
bulk, highly vascular Pars Intermedia –
middle, avascular zone Pars Tuberalis – most
vascular, contains secretory cells.
Monday, May 1, 2023
NEUROHYPOPHYSIS. Post lobe – Neural structure. 3 parts
Pars Posterior – pars nervosa , forms main bulk.
Infundibular Stem – arising from median eminance
Median Eminance – small portion from base of hypothalamus..
Monday, May 1, 2023
PITUITARY STALK. Median eminence &
Infundibulum forms neural stalk.
Surrounded by Pars Tuberalis of Adenohypophysis.
Monday, May 1, 2023
INTERMEDIATE LOBE Rudimentary & does not secrete
Melanocyte stimulating hormones(MSH).
Humans contains few Melanocyte containing melanin granules.
ACTH has weak MSH like activity, so in Addison's disease Hyper secretion of ACTH, there is hyper pigmentation of skin.
Monday, May 1, 2023
HISTOLOGICAL STRUCTURE Adenohypophysis
Chromophobes - Agranular Chromophils – Granular
Acidophils (35%) Somatotrophs Mammotrophs.
Basophils (15%) Corticotrophs, Thymotrophs,
Gonadotrophs.
Folliculostellate cells Capillary network.
Monday, May 1, 2023
HISTOLOGICAL STRUCTURE Neurohypophysis.
Unmyelinated nerve fibers – axons in supraoptic & paraventricular nuclei of hypothalamus.
Pituicytes – Special types of supporting cells.
Glial cells – like Astrocytes & Oligodendrocytes.
Monday, May 1, 2023
BLOOD SUPPLY OF PITUITARY GLAND
ARTERIAL SUPPLY Internal carotid artery
(sup & inf hypophyseal branches)
Anterior cerebral artery. Posterior cerebral
artery.
VENOUS DRAINAGE Cavernous sinus Jugular veins.
Monday, May 1, 2023
HYPOTHALAMO-HYPOPHYSEAL PORTAL SYSTEM.
From superior hypophyseal artery, form capillary network.
Drained by long portal veins in Infundibulum.
Break into capillaries as sinusoids of pars anterior as portal system
Provide link between ant & post pituitary.
Monday, May 1, 2023
HYPOTHALAMIC PITUITARY RELASHIONSHIP
Hypothalamo-hypophyseal tract.
Tubero-infundibular tract and hypothalamo-hypophyseal portal system.
Monday, May 1, 2023
HYPOTHALAMO-HYPOPHYSEAL TRACT.
Axons of large Neuro secretory cells of supraoptic & paraventricular nuclei of hypothalamus.
At axon terminal form Herring bodies.
Secrete peptide hormones & stored in Neuro secretory granules in nerve terminals.
Released in inferior hypophyseal artery.
Monday, May 1, 2023
TUBERO-INFUNDIBULAR TRACT AND HYPOTHALAMO-HYPOPHYSEAL
PORTAL SYSTEM.
Monday, May 1, 2023
Monday, May 1, 2023
ANTERIOR PITUITARY HORMONES
ANTERIOR PITUITARY - master endocrine organ
Adenohypophysis hormones Growth hormone family. Glycoprotein hormone
family. Pro-opiomelanocortin
peptides family.
Monday, May 1, 2023
Monday, May 1, 2023
GROWTH HORMONE FAMILY. Growth hormone Prolactin. Human chorionic
Somatomammotropin.
Monday, May 1, 2023
GLYCOPROTEIN HORMONE FAMILY.
Thyroid stimulating hormone
Luteinizing hormones
Follicle stimulating hormones.
Monday, May 1, 2023
PRO-OPIOMELANOCORTIN PEPTIDES FAMILY.
Derived from single precursor – Pro-
opiomelanocortin
Adrenocorticotropic hormone
Melanocyte stimulating hormone
β- lipotropin
β-endorphin
Monday, May 1, 2023
OBJECTIVES WE HAVE SEEN Pituitary gland – macroscopic & Microscopic
structure. Relationship with Hypothalamus. Releasing & Inhibiting Hormones. Anterior pituitary gland Cells, secretions and different hormones.
Monday, May 1, 2023
Thank you.
Monday, May 1, 2023