parathyroid and pituitary gland by dr roomi
TRANSCRIPT
8/3/2019 Parathyroid and Pituitary Gland by Dr ROOMI
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HISTOLOGY OF
ENDOCRINE GLANDS
BY
DR. MUDASSAR ALI ROOMI (MBBS, M. Phil.)
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Parathyroid Glands
Separated from thyroid by
its Capsule.
Mammals have four
glands, situated onposterior surface of
thyroid
thin septa of C.T contains
collagen and elastic fibers
Instead of follicles, cellsarranged in cords or
clumps
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Parathyroid Glands
Principal Cells or chief cells
Polygonal cells
Pale stain, slightlyacidophillic cytoplasm
Most numerous cells
Secrete PTH
Oxyphil Cells (start appearingafter 7 years)
Darkly eosinophilic(because of a lot of mitochondria in thecytoplasm)
Large Polygonal cells, largerthan Principle cells
Adipose Cells, increase with age (older 50% of all cells!)
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CALCIUM HOMEOSTASIS
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CLINICAL IMPORTANCE OF PTH
HYPERPARATHYROIDISM:
hypophosphatemia and hypercalcemia.
pathologic deposits of calcium in severalorgans, such as the kidneys and arteries.
multiple bone cavities, is this diseases is
known as osteitis f ibrosa cystica. Pathologic fractures.
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HYPOPARATHYROIDISM,
hyperphosphatemia and hypocalcemia.
Tetany may occur. exaggerated excitability of the nervous
system, due to the lack of Ca2+ in the blood.
Chvostek sign, trousseus sign
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PITUITARY GLAND (THE HYPOPHYSIS
CEREBRI)
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Pituitary gland
Master gland
It lies in the base of the
skull in a portion of
sphenoid bone called
sella turcica
weight= 500-900 mg
Size is like that of pea. It may double in size
during pregnancy
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Gross anatomy of Pituitary gland
Adenohyphophysis= parsdistalis+ parsintermedia+parstuberalis.
neurohypophysis= parsnervosa+ infundibularstem+median eminance
Anterior pituitary= parsdistalis+ pars tuberalis
Posterior pituitary= parsintermedia and parsnervosa.
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Development of Pituitary gland
Adenohypophysis is
derived from oral
ectoderm.
Neurohypophysis is
derived from the floor
of diencephalon
(forebrain).
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The Hypothalamic-Hypophyseal Portal System
2 capillary beds directly joined by blood vessels
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Histology of the Pituitary Gland
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Histology of the Pituitary Gland
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PARS DISTALIS
75 % of the hypophysis.
Surrounded by a C.T. capsule.
Parenchyma= cords and
clusters of cells. Cells of parenchyma=
chromophobes, chromophils.
Stroma = composed of
reticular fibers and fibroblasts.
b/w the cellular masses
sinusoidal capillaries are
present.
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PARS DISTALIS
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Chromphobes:
No affinity for stains
50 % cells in the pars disatalis.
Rounded or polygonal cells
No secretory granules
Actually these are degranulated chromophils.
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Chromphils:
Remaining 50 % of the cells.
Rounded or polygonal cells Have affinity for stains due to presence of
cytoplasmic granules.
2 types: acidophils (70%) and basophils.
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Acidophils:
Larger than chromophobes but smaller than
basophils Cytoplasm has granules which stain with aciidc dyes
(e.g. eosin, orange G, azocarmine etc)
Alpha acidophils (somatotropes): commoner of the
two types, stain well with orange G. secrete GH.
Epsilon acidophils (lactotropes or mammotropes):
Granules stain with azocarmine. Secrete prolactin.
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Basophils:
Larger in size than acidophils
Dont stain with hematoxylin but stain intensely withmethylene blue.
Beta basophils (thyrotropes): stain intensely with
aldehyde fuchsin. secrete TSH.
Delta cells (gonadotropes): secrete FSH and LH.
Corticotropes: these cells also dont stain with
aldehyde fuchsin. They secrete ACTH.
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NEUROHYPOPHYSIS
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Anterior pituitary hormones: (GH, PRL, TSH, ACTH,
LH, FSH).
Posterior pituitary hormone: vasopressin (ADH),
oxytocin.
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