An ultrastructural analysis of the developing embryonic pancreas

摘要: This ultrastructural analysis of pancreas development under in vivo and vitro conditions complements earlier biochemical studies. The endocrine exocrine tissue develops similarly vitro. early pancreatic epithelial cells, like those the gut, form a single layer cells facing lumen, are linked together by junctional complexes. cellular polarization implies constraint for axis division demands that loose their connection with order to islets. presence mitotic figures well differentiated acinar suggests cell multiplication is not incompatible differentiation. first zymogen granules can be observed look similar present later development. observation “prozymogen granules” which were reported papers probably result fixation artifacts, did represent stage granule formation between condensing vacuoles Golgi definitive granules. The morphological observations this study consistent previously proposed biphasic model differentiation B cells. specific organelles correlates pattern accumulation proteins insulin. On other hand, A when bud forms. appearance regulatory role hormone