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ENDOCRINE GLANDS PowerPoint Presentation
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ENDOCRINE GLANDS

ENDOCRINE GLANDS

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ENDOCRINE GLANDS

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  1. ENDOCRINE GLANDS Dr Iram Tassaduq

  2. 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

  3. 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.

  4. CORTEX • zona glomerulosa - thin, outermost zone • zonafasiculata - thick, middle zone • zonareticularis - thin, inner zone

  5. ZONA GLOMERULOSA • Composed of columnar or pyramidal cells arranged as rounded or arched cords • Occupy 15% of gland volume

  6. ZONA GLOMERULOSA

  7. 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

  8. ZONA FASICULATA

  9. ZONA RETICULARIS • Polyhedral cells with lipid droplets • Form 7% of gland • Appears vacuolated in histological preparations • Cells are smallest in size

  10. ZONA RETICULARIS

  11. 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

  12. ADRENAL MEDULLA

  13. FUNCTIONS OF ADRENAL GLAND

  14. THYROID GLAND

  15. C.T. sheath formed by deep cervical fascia • Extremely labile gland & varies in size & structure

  16. Three dimensional view of thyroid follicles

  17. 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

  18. STRUCTURAL UNIT OF THYROID GLAND ----- THYROID FOLLICLE

  19. FOLLICULAR EPITHELIUM Follicular cells Para follicular cells

  20. FOLLICULAR CELLSPRINCIPAL/ CHIEF CELLS • Responsible for the production of T3 & T4 • Vary in size & shape • Slightly basophilic in H & E stained slides • Lipid droplets

  21. 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 COLLOID

  22. 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

  23. FUNCTION OF THYROID GLAND

  24. Two pairs in mammals Embedded within thyroid gland substance C.T. capsule is thin PARATHYROID GLAND

  25. More numerous of parenchymalcells Small, polyhedral cells, of 7-10 um in diameter Rounded, vesicular nuclei Responsible for secretion of PTH PRINCIPAL CELLS/ CHIEF CELLS chief cells

  26. 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