Surface features and behavior of the connective tissue cell.

The surface features and behavior of the connective tissue cell in normal areas and in healing incisions of the aponeuroses of the abdominal wall of the albino rat were studied with the scanning electron microscope (SEM). The normal cell is smooth, oval or triangular in outline and has a generally rounded surface and very short or no cell processes. The behavior of the fibroblasts and the condition of the fibers in and around the wounds were visualized. Shortly after the incision, the fibroblasts accumulated around the wound, possibly by increased cell division. At the site of the incision the cells responded by a self-protective mechanism in which they withdrew their processes and acquired a spheroid form. During the maximum period of a fibrillogenesis the fibroblasts enlarged, acquired a fusiform outline and long processes, exhibited a roughened surface and were surrounded with small rounded cell particles polymerizing into fine fibrils. The process of collagen secretion and three stages of collagen maturation were visualized. Some abnormal cells were seen; they could be evidence of merocrine or holocrine mode of secretion or possibly signs of cell senility.