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 Cellsorchiefcells

Polygonal cells

Pale stain, slightlyacidophillic cytoplasm

Most numerous cells

Secrete PTH

Oxyphil Cells(start appearingafter 7 years)

Darkly eosinophilic(because of a lot ofmitochondria in thecytoplasm)

Large Polygonal cells, largerthan Principle cells

Adipose Cells,increase withage (older 50% ofall 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 fibrosa 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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Pituitarygland

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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Grossanatomyof Pituitarygland

Adenohyphophysis= parsdistalis+ parsintermedia+parstuberalis.

neurohypophysis= parsnervosa+ infundibularstem+median eminance

Anteriorpituitary= parsdistalis+ pars tuberalis

Posteriorpituitary= parsintermedia and parsnervosa.

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DevelopmentofPituitarygland

Adenohypophysis is

derived from oral

ectoderm.

Neurohypophysis isderived 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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Histologyofthe Pituitary Gland

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Histologyofthe 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)

Alphaacidophils (somatotropes): commoner of the

two types, stain well with orange G. secrete GH.

Epsilonacidophils (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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Anteriorpituitaryhormones: (GH, PRL, TSH, ACTH,

LH, FSH).

Posteriorpituitaryhormone: vasopressin (ADH),

oxytocin.

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