Gross, histomorphological and histochemical changes in thyroid gland of goat with age. II. Occurrence of ultimobranchial follicles.
Occurrence and histomorphology of ultimobranchial follicles in the thyroid glands of 26 goats of six different age groups (ranging from 20 days to above five years) was studied. The occurrence of ultimobranchial follicles was 38.46%. In 15.38% of the cases, it was found with and in 23.08% without any association of the thymic tissue. Its association with parathyroid tissue has also been recorded in one of the goats aged 7 months 11 days. Their size and shape varied greatly and were narrow and wide tubular, epithelial pear like, long follicle with colloid, sheet of stratified squamous cells attached to follicle, bilobed, evaginated and a group of follicles. The latter three forms of follicles were due to the branching of main stem UB follicle, present at different levels. They were located in perivascular connective tissue in the deeper zone of the thyroid gland but their presence in periphery of thyroid gland within the capsule was not uncommon. The epithelial lining of these follicles was highly variable from simple squamous to columnar with or without cilia which may be stratified. Light cells were seen among epithelial lining. The lumen of the follicles was filled with nucleated, non-nucleated and colloid debris which was PAS-positive. In older animal colloid contained acid mucopolysaccharides.
D000375:Aging; D000818:Animals; D006041:Goats / Q000033:anatomy & histology*; D006651:Histocytochemistry; D013961:Thyroid Gland / Q000033:anatomy & histology* / Q000378:metabolism; D014460:Ultimobranchial Body / Q000166:cytology