1. ENDOCRINE GLANDS

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

5. 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.

6. CORTEX zona glomerulosa - thin, outermost zone
zona fasiculata - thick, middle zone
zona reticularis - thin, inner zone

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

8. ZONA GLOMERULOSA

9. 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

10. ZONA FASICULATA

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

12. ZONA RETICULARIS

13. 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

14. ADRENAL MEDULLA

15. FUNCTIONS OF ADRENAL GLAND

16. THYROID GLAND

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

18. Three dimensional view of thyroid follicles

19. 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

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

21. FOLLICULAR EPITHELIUM
Follicular cells
Para follicular cells

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

23. 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

24. PARAFOLLICULAR CELLS C 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

26. FUNCTION OF THYROID GLAND

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

31. 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

33. 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