Annie Doley

BACKGROUND The sub-Himalayan region is known to be world’s biggest goiter belt in India, but no state can be said to be entirely free from goiter. There is a high incidence of thyroid disorder in the northeastern region of India. In view of this, a comparative histological study of thyroid gland in mammals was conducted in the Department of Anatomy, Gauhati Medical College, Guwahati. MATERIALS AND METHODS The mammals included for this study were humans, pig and goat. The thyroid gland was meticulously dissected out, cut into small pieces, fixed in formalin and embedded in paraffin was sectioned and stained in haematoxylin and eosin. Slides were observed under microscope. The diameter of thyroid follicles were measured with the help of micrometer slide and the results were statistically analysed and compared. RESULTS The histology of thyroid gland was studied in three mammals human, pig and goat. Slides of all three mammals showed similar structures consisting of closely packed follicles of variable sizes. Follicles were lined by follicular cells. Parafollicular cells were also seen, which were little larger and lighter stained. Thus, all three mammals showed similar cytoarchitecture. CONCLUSION The histological structure of all the mammals were found to be familiar. All mammals showed follicles, follicular cells and parafollicular cells