Detailed explanation of histology of the endocrine system of the bidy

1. Endocrine Glands
Dr Punita Manik
Professor
Department of Anatomy
K G’s Medical University U P
Lucknow

2. Endocrine Glands
Discrete organs
• Pituitary
(Hypophysis cerebri)
• Thyroid
• Parathyroid
• Adrenal(Suprarenal)
• Pineal
Association with organs
• Islet of Langerhans
• Interstitial cells of
Leydig
• Ovarian Follicle &
Corpus luteum
• Chorion
• Lacis cells, JG cells
• Enteroendocrine cells

3. Thyroid
Composed
• Stroma –
capsule and
intralobular
loose
connective
tissue
• Parenchyma
- thyroid
follicles

4. Parenchyma-Thyroid
Follicles
• Lined by cuboidal
epithelium
• Height of the
follicular cells varies
with the secretory
activity of the gland
• Cells secrete T3 and
T4
Lumen filled with
colloid or Thyroglobulin-
inactive form of thyroid
hormones

5. Thyroid
• In the same
gland, active and
resting follicles
are seen
• Resting
• Active
• Secretory activity
is under the
control of TSH of
adenohypophysis

6. Thyroid

7. Resting and active Follicle

8. Parafollicular cells
• Also known as C cells of Clear cells
• Large pale staining cells , granular cytoplasm
• Present either singly or in groups
• Within the follicle or between the follicles in
the interfollicular space
• Those within the follicle lie between the
basement membrane and the follicular cells
• Secrete Thyrocalcitonin or Calcitonin
• Calcitonin lowers blood calcium level

9. Parathyroid
• STROMA- capsule and
septa
• PARENCHYMA-
secretory cells arranged
in clusters or
anastomosing cords
• 2 type of cells
• Chief cells Or Principal
cells
• Oxyphil cells

10. Parathyroid

11. Parathyroid
• Chief Cells-small, Basophilic, in large nos
• Oxyphil cells- Large, eosinophilic, small no
Chief cells- secrete Parathromone or
Parathyroid hormone
• Parathyroid hormone
Increases Calcium Level
Decreases phosphate
Level in blood

12. Parathyroid

13. Pituitary Gland

14. Ant & Post Pituitary

15. Cells of Anterior Pituitary
• Granular Cells arranged in
irregular cords or clusters
• Based on the affinity of
granules for specific stains:
Chromophils &
Chromophobes
• Chromophils: Darkly
stained because of stained
granules
• Chromophobes: Poorly
stained as no or few
granules

16. Cells of Anterior Pituitary

17. Acidophils and Basophils

18. Chromophils
Acidophils
• Shape: Round or oval
• Stain with orange G or
Erythrosin
• Somatotrophs and
Lactotrophs
• Secrete GH and
Prolactin
Basophils
• Large, rounded or
polyhedral
• PAS +
• Gonadotrophs (LH,
FSH) Thyrotrophs(TSH),
Corticpotrophs(ACTH
and MSH)

19. Anterior & Posterior Pituitary

20. Posterior Pituitary
Numerous
unmyelinated
nerve fibres
which are
axons of
neurons
located in the
Hypothalamus
Arising from
supraoptic and
Paraventricular
Nuclei
Supporting
cells between
them are
pituicytes

21. Anterior & Posterior Pituitary

22. Pituitary Gland

23. Adrenal
Adrenal Cortex: 3 zones
• Zona Glomerulosa
• Zona fasciculata
• Zona Reticularis
• Cells of cortex has
characteristic features of
steroid formation:
• Cells have many
mitochondria with long
tubular cristae and
smooth endoplasmic
reticulum where enzymes
for steroid synthesis are
found
• Secretory activity under
the control of ACTH

24. Adrenal Gland

25. Adrenal
Z. Glomerulosa
• Rounded or arched
clusters of pyramidal cells,
acidophilic cytoplasm
with lipid droplets
• Fenestrated capillaries are
found among the cluster
of cells

26. Adrenal
Z. Fasciculata
• Straight parallel cords cords
of polyhedral cells, pale
staining cytoplasm with lipid
droplets
• Lipid droplets give vacuolated
or spongy appearance known
as spongiocytes
• Fenestrated capillaries seen
between the cord of cells

27. Zona Glomerulosa and Zona
Fasciculata

28. Adrenal
Z Reticularis
• Small, more acidophilic cells
• irregular anastomosing
cords of cells
• Cells have elongated
mitochondria,glycogen,
lipofuscin pigments and few
lipid droplets

29. Adrenal
Medulla
• Clumps or cords of
chromaffin cells
• Polyhedral in shape with
few fenestrated
capillaries in between
• Also contains
parasympathetic ganglion
cells

30. Adrenal-chromaffin cells
• Derived from Neural
crest cells
• Are modified
sympathetic
postganglionic neurons
• Stain with chromium
salts
• Catecholamines are
oxidized to brown
compound- Chromaffin
reaction.

31. Chromaffin cells of Medulla

32. Difference between cells of Cortex
and Medulla
Cortex
• Under the control of ACTH
• Cells do not accumulate
their hormones in granules.
They synthesize and
secrete only on demand
Medulla
• Neural Control as
innervated by modified
sympathetic postganglionic
neurons
• Cells accumulate and store
secretory products in their
granules

33. Adrenal Gland

34. Pineal Gland (Epiphysis)
Main cells- Pinealocytes- modified Neurons
Other cells-Astroglial cells

35. Pineal Gland (Epiphysis)
Brain sand or Corpora arenacea-concentric rings of
Ca & Mg Po4

36. Pineal gland

37. MCQ
• Parafollicular cells are present in which of the
following endocrine glands?
1. Parathyroid
2. Suprarenal
3. Thyroid
4. Pancreas

38. MCQ
• Which part of the hypophysis cerebri
contains Herring Bodies?
1. Pars anterior
2. Pars posterior
3. Pars tuberalis
4. Pars intermedia

39. MCQ
• Adenohypophysis contains all type of cells
EXCEPT?
1.Chromophobes
2. Acidophils
3. Basophils
4. Pituicytes

40. MCQ
• The active follicles of thyroid gland are lined
by
1. Simple squamous epithelium
2. Simple cuboidal epithelium
3. Simple columnar epithelium
4. Stratified cuboidal epithelium