Peritoneal mesothelium and ovarian surface cells--shared characteristics.

This is a transmission electron microscopy study of peritoneal mesothelium and surface cells covering the ovary. One thousand two hundred cells derived from 22 samples of peritoneum and 1,200 derived from 22 samples of ovary were compared for cell size, length-to-diameter ratio, and distribution and complexity of surface villi. Cilia were looked for. Other factors studied included mitochondria, pinocytosis, secretory vacuoles, tonofilaments, desmosome-tonofilament complexes, lysosomes, and mucin. In general, peritoneal mesothelial cells tend to be flat, and surface cells of the ovary, cuboidal. The villous surfaces are essentially similar. Two ciliated cells were found in 1,200 surface cells of the ovary; one blunted cilium was found in 1,200 peritoneal cells. Mitochondria, pinocytosis, secretory vacuoles, and lysosomes were essentially similar in both cell types. Desmosome-tonofilament complexes were rare in surface cells and not found in mesothelial cells. Tonofilaments were present in 340 of 1,200 peritoneal mesothelial cells (28.30%). They were present in only 16 of 1,200 surface cells of the ovary (1.33%). It appeared that peritoneal mesothelium and surface cells of the ovary are, in most respects, structurally similar.