PP Endocrine
PP Endocrine
PP Endocrine
3
Endocrine Organs
• Cells forming endocrine
organs
– Pituitary gland
– Thyroid gland
– Parathyroid glands
– Adrenal: 2 glands Cortex
Medulla
-Pineal gland
• Endocrine cells in other
organs
– Pancreas
– Thymus
– Gonads
– Hypothalamus
4
Pituitary gland…
1.Hypophysis (Pituitary Gland)
• The hypophysis consists of glandular (Adenohypophysis) &
nervous portions (Neurohypophysis)
Basophils-
Cells are variable in sixe and
shape with basophilic
cytoplasm.
secretory granules
responsible for the staining
characteristics of these cells
are.
Anterior pituitary…
Chromophobe :
Interfollicular regions –
the presence of connective
tissue, sinusoidal capillaries
into which hormone is released)
parafollicular cells
Thyroid Follicles
• Follicular epithelium:
vary from high cuboidal to low
cuboidal ; reflects the level of
follicle secretory activity.
follicle cells (principal cells)
have large, centrally- or
basally-located nuclei,
cells active in protein secretion.
Storage and release of thyroid
hormones involves the protein
thyroglobulin .
Parafollicular Cells
Found scattered singly or in
small groups present in
periphery of the follicles ,
cells are responsible for
production of calcitonin, a
peptide hormone that is
synthesized and secreted
independently of thyroid
hormone.
Also called C, clear, or light
cells.
Parafollicular Cell…
Oxyphil cells:
single or clumps of larger
cells with acidophilic
(oxyphilic), cytoplasm
with dark staining nucleus.
Number inrease with age.
Oxyphil cells are not
always present in a section
of parathyroid gland.
Adrenal gland…
Adrenal Glands…
Like the pituitary, they are composed
of two distinctly different components,
one of mesothelial origin and one of
neural origin .
General Structure
• outer cortex , and the inner medulla .
These zones are readily observed even
in a fresh, unstained section.
• 3 histological zones of the cortex.
• tough connective tissue capsule and
radial trabeculae that extend into the
cortex.
• Prominent central vein in the medulla.
Adrenal Cortex…
medulla
Adrenal Cortex: Zona Glomerulosa
Identify…
• outermost cortical layer , and
note the presence of columnar
epithelial cells arranged in
long cords that appear as ovoid
clumps when cut in cross-
section.
• cytoplasm is pink and relatively
scant contain lipid droplets.
• capillary sinusoids are abundant.
Adrenal Cortex: Zona Fasciculata…
• Basophilic, extracellular
concretions . They are often
calcified, which makes the
pineal gland an excellent
radiological marker,
particularly of the midline.
Epiphysis (Pineal Gland)
• The pineal is innervated by
unmyelinated axons of
postganglionic sympathetic
neurons. This is an unusual
example of a central nervous
system structure that receives
sympathetic innervation.
• Presence of a rich vascular
supply characteristic of all
endocrine glands.
Endocrine Pancreas: Islets of Langerhans
• The pancreas is a mixed exocrine
and endocrine gland.
General Structure
• Note that islet cells are found as
clumps of small secretory cells
with relatively lightly-stained
cytoplasm present in connective
tissue .
• Compare their appearance to that of
the prolific protein-secreting cells
of exocrine pancreatic acini .
• Identify the rich network of
capillaries that characterize all
endocrine organs.
Islet of Langerhans…