Light micrograph of normal human parotid gland. One of the salivary glands, the parotid consists of acini whose secretion is entirely serous (watery). Most of the field here shows, in cross section, the secretory cells which comprise the acini. The prominent ring-shaped structures with many red nuclei and faint radial striping at their periphery are striated ducts. The blue stained cells forming boundaries around the striated ducts are conncetive tissue. Three blood vessels are visible, lying next to the ducts (e.g. centre top), containing orange stained red blood cells. Magnification: x50 at 35mm size.