In the tight junction area, the P fracture face (lower part of the image) contains a dense network of anastomosing strands (fibrils). The strands are formed by closely packed linear intramembrane particles. These particles are integral membrane proteins called occludins and claudins, which belong to a vast family of junctional adhesion molecules. It is considered that the extracellular domains of claudins interact with matching segments of a neighboring cell membrane proteins to form exactly the reticular structure restricting the intercellular space.

The image also shows an opened acinar lumen of the pancreas. In these cells, there are some large spherical pits of the apical cytoplasm, which are secretory granules #1, #2, or rather their fractured membranes.