inclusion pigment

Inclusions are diverse intracellular non-living substances(ergastic substances) that are not bound by membranes. Inclusions are stored nutrients/deutoplasmic substances, secretory products, and pigment granules. Examples of inclusions are glycogen granules in the liver and muscle cells, lipid droplets in fat cells, pigment granules in certain cells of skin and hair, and crystals of various types.

The most common pigment in the body, besides hemoglobin of red blood cells is melanin, manufactured by melanocytes of the skin and hair, pigments cells of the retina and specialized nerve cells in the substantia nigra of the brain. These pigments have protective functions in skin and aid in the sense of sight in the retina but their functions in neurons is not understood completely.