WANDERING THYROID FOLLICLES WITHIN THE RENAL TISSUE OF CARP FISH "Cyprinus Carpio".

Abstract

Twenty healthy adult Carp fish were collected from Dijlah river in Iraq inSummer and winter times of the year (Ten for each ). The fish were sacrificed andfixed in 10% neutral buffered formalin solution. Routine histological preparationswere carried out. Hematoxylin - Eosin stain was used. The finding of the current studyshowed that clear connective tissue capsule was not observed. Instead, wide looseconnective tissue was surrounded the follicles. The thyroid follicles were distributedindividually or in groups in the kidney and sub pharyngeal region( around the ventralaorta). The thyroid tissue was represented by thyroid follicles of different sizes andshapes. In Carp fish, the building up and organization of the follicular cells of thyroidfollicles were simple and poorly organized. There was a close relationship betweenthe morphological state of thyroid follicles and the season( temperature). The resultsof the present study also demonstrated that the spread of thyroid follicles in summerwas more than in winter where the follicles appeared as aggregated at the peripheryof renal tissue and also the results of this study showed that large and small follicleswere combined. The study also registered that, during winter, the large follicles weremostly formed by the aggregation of smaller ones and that according to thephysiological status of the thyroid tissue. The study concluded firstly that thesefollicles had the ability to wandered within the renal tissue. Moreover, the studyconcluded that the thyroid follicle was dynamic structure, and their sizes dependingon the amount of colloid present within .