Panoramic observation of the mouse gastric mucosa by superwide-field electron microscopy.

Transitional changes in cell population and ultrastructure in the gastric mucosa can be clearly demonstrated by superwide-field electron microscopy. A few undifferentiated cells as well as immature forms of the surface mucous, mucous neck and parietal cells are present in the lower part of the isthmus or the upper part of the neck. Surface mucous cells and mucous neck cells show maturer morphology with their migration to the mucosal surface or to the deep part of the neck, respectively. Parietal cells may migrate either upwards or downwards. Immature chief cells appear in the uppermost part of the base and mature as they migrate towards the gland bottom. A transition from mucous neck cells to chief and parietal cells is suggested. Collagen fibers and fibroblasts are more numerous in the foveola and isthmus regions than in deeper parts of the mucosa. Smooth muscle fibers are separated from the muscularis mucosae and run perpendicularly to the mucosal surface.