par Wollman, Seymour S.H.;Neve, Pierre 
Référence The Anatomical record, 171, 2, page (247-258)
Publication Publié, 1971
Référence The Anatomical record, 171, 2, page (247-258)
Publication Publié, 1971
Article révisé par les pairs
| Résumé : | Mature ultimobranchial follicles in the Fischer rat thyroid are characterized by being lined by two or more layers of cells (U cells) and by having an abundance of desquamated cells in the lumen. Such follicles, of variable size and shape, were found in almost every lobe in rats at least 30 days old. They were usually in the interior of the lobe in contact with perivascular connective tissue. Ultimobranchial follicles with multiple layers of cells were not observed in the two‐day‐old rat indicating that these follicles are an example of postnatal development. The most common precursor in the rat was a follicle, relatively large compared with the usual thyroid follicle, containing some cells or debris. Other precursor structures included narrow tubes, sheets or spheroids of cells characteristically having little cytoplasm. Intermedlate forms between these precursors and mature ultimobranchial follicles were recognized. Cells were desquamated while nucleated, and, later, the nuclei disappeared. Thus, in some follicles non‐nucleated debris accumulated. Many follicles were composed of mixed populations of cells, both typical thyroid epithelium and U cells. The relative abundance of the two cell types varied markedly as did the proportions of colloid and cell debris. Copyright © 1971 Wiley‐Liss, Inc. |
