Epithelial junctional complex in apical-based sequence of intestinal epithelium of a rat. Composed of the zonula occludens, the zonula adherens, and the macula adherens. The zonula occludens is a belt-like specialization in which the adjacent unit membranes converge and fuse, obliterating the intercellular space over variable distances. The membranes commonly fuse at multiple levels within the zonula to form local pentalaminar regions separated by short segments in which the membranes are closely opposed, but not fused. At the zonula adherens, the membranes course parallel over a distance of 0.2 to 0.5 micrometers, and are separated by a 25 nanometer of interstellar space. The cytoplasm immediately subjacent to the membranes is relatively dense, and is the site of insertion of the transversely oriented filaments comprising the so-called "terminal web." The desmosome is the third component of the complex. It consists of parallel segments of the opposing membranes, reinforced by dense plaques, and separated by aan interspace of about 25 nanometers, which is often bisected by a thin, dense line. THE CELL 2nd edition.