pigmentary epithelium, pigmented epithelium. that made of cells containing granules of pigment. posterior epithelium. the single layer of epithelial cells on the back of the cornea, between stroma and aqueous humour; the corneal endothelium.retinal pigment epithelium. see retina.sense epithelium, sensory epithelium. see neuroepithelium (1).he single layer of epithelial cells on the back of the cornea, between stroma and aqueous humour; the corneal endothelium. retinal pigment epithelium. see retina. sense epithelium, sensory epithelium. see neuroepithelium (1).
Since at least the mid-19th century, doctors have known that silver or silver compounds can cause some areas of the skin and other body tissues to turn grey or blue-grey. Argyria occurs in people who ingest or inhale
Similar to iron and aluminum, the element copper undergoes the process of oxidation, if it is exposed to air. If the atmosphere consists of high humidity moisture, then this process is faster. The copper metal reacts with oxygen, resulting in the formation of an outer layer of copper oxide, which appears green or bluish-green in color. This layer is known as the patina. Unlike other destructive oxidation processes, the patina acts as a protective layer, and it does not cause any weakness in the metal.