Post on 23-Feb-2016
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ENDOCRINE GLANDS
Dr Iram Tassaduq
ADRENAL (SUPRARENAL ) GLAND
• Lies on upper pole of each kidney
• Comprised of two zones outer cortex inner medulla• Develops from
intermediate mesoderm and neural crest cells
INTRODUCTION• The adrenal gland is
encased in a connective tissue capsule that extends septae into the substance of the gland. The organ is richly vascularized and capsular blood vessels, nerves and lymphatics penetrate along with the connective tissue septae.
CORTEX• zona glomerulosa - thin,
outermost zone • zona fasiculata - thick,
middle zone • zona reticularis - thin,
inner zone
ZONA GLOMERULOSA
• Composed of columnar or pyramidal cells arranged as rounded or arched cords
• Occupy 15% of gland volume
ZONA GLOMERULOSA
ZONA FASICULATA
• Cells are arranged in straight cords. 1-2 cells thick
• Cords run at right angles to the surface of organ and have capillaries between them
• Occupy 65% of gland volume
ZONA FASICULATA
ZONA RETICULARIS
• Polyhedral cells with lipid droplets
• Form 7% of gland• Appears vacuolated in
histological preparations
• Cells are smallest in size
ZONA RETICULARIS
ADRENAL MEDULLA
• Composed of cords or clumps of cells called chromaffin cells. These can acquire brown colour which is due to oxidation of catecholamines
• Modified postganglionic sympathetic neurons
ADRENAL MEDULLA
FUNCTIONS OF ADRENAL GLAND
THYROID GLAND
• C.T. sheath formed by deep cervical fascia
• Extremely labile gland & varies in size & structure
Three dimensional view of thyroid follicles
DEVELOPMENT OF THYROID GLAND
• Begins to develop during 4th week of gestation from a primordium originating as an endodermal thickening of floor of primitive pharynx
STRUCTURAL UNIT OF THYROID GLAND ----- THYROID FOLLICLE
FOLLICULAR EPITHELIUM
Follicular cells
Para follicular cells
FOLLICULAR CELLSPRINCIPAL/ CHIEF CELLS
• Responsible for the production of T3 & T4
• Vary in size & shape• Slightly basophilic in
H & E stained slides• Lipid droplets
COLLOID• Inactive storage form
of thyroid hormone• Constituents• Principal component
is thyroglobulin (large iodinated glycoprotein)
• Enzymes• Glycoproteins
• Staining with both acidic & basic dyes. Strongly with PAS
PARAFOLLICULAR CELLSC CELLS/ CALCITONIN CELLS
Located in periphery of follicular epithelium
No exposure to lumen In H & E stained slides
appear as pale staining cells
Secrete calcitonin
FUNCTION OF THYROID GLAND
PARATHYROID GLAND
• Two pairs in mammals
• Embedded within thyroid gland substance
• C.T. capsule is thin
PRINCIPAL CELLS/ CHIEF CELLS
• More numerous of parenchymal cells
• Small, polyhedral cells, of 7-10 um in diameter
• Rounded, vesicular nuclei
• Responsible for secretion of PTH
chief cells
OXYPHILL CELLS• Constitute a minor
portion of parenchyma• Found singly or in
clusters• More rounded & larger
than principal cells• Distinctly acidophilic
cytoplasm• No secretory activity