Thyroid Gland by Dr Roomi

8/3/2019 Thyroid Gland by Dr Roomi

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HISTOLOGYOF

THYROID AND PARATHYROID GLANDS

BY

DR. MUDASSAR ALI ROOMI (MBBS, M. Phil.)


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THYROID GLAND

LOCATED IN THE LOWER PART OF NECK

BILOBED STRUCTURE

CONNECTED BY ISTHMUS

A HIGHLY VASCULAR GLAND


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CLINICAL PROBLEMS OF THYROID

HYPOTHYROIDISM HYPERTHYROIDISM


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THYROID AND PARATHYROID GLANDS


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THYROID GLAND

Components:

1. True Capsule

2. C.T. Stroma

3. parenchyma


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TrueCapsule: Narrow layer of dense

connective tissue


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HISTOLOGY OF THYROID GLAND


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Parenchymaofthyroid

made by the thyroid follicles andpara-follicular cells.

Folliclesare round, oval, or

irregular in outline, completelyclosed (diameter= 0.02-0.9 mm)

Simple cuboidal epithelium with ahollow centers containing colloid.

Epithelium may become simplesquamous (inactive state) or simplecolumnar (hyperactivity state).

Thin basement membrane ispresent around the follicles. It issurrounded by fenestratedcapilaries.


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HISTOLOGY OF THYROID GLAND


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Colloid

gel like, clear material.

It is glycoprotein in nature

(iodinated thyroglobulin).

stored secretion, 10months supply!

effect of processing of

tissue on colloid= it is

coagulated and mayshows irregularities under

microscope.


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Parafollicular cellsor C (Clear) Cells

Present as singly or as small isolated clusters of cells outsideof follicles.

Cells are larger than follicular cells.

Pale staining cells(secrete Calcitonin)

PTH antagonist (lowers Ca level), blocks osteoclast activity

C-cells act independent of pituitary gland hormones, instead

depend on plasma calcium level.


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Thyroid Gland by Dr Roomi

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