Morphogenetic types of cuticles and melanin granules in the anagen phase of hair follicles

Abstract

Our studies on the scalp and hair follicles have a particular interest in the formation of white hair and melanin; however, representative images of white hair and melanin formation have been difficult to find. The morphogenetic types of melanosomes and cuticles in hair follicles are diverse. The generated form of melanin granules include soft melanosomes that penetrate through the outer root sheath (ORS) of the hair follicle where they remain between the ORS and the inner root sheath (IRS) as irregular large masses of soft melanosomes. Subsequently, they break into small fragments, pass though the IRS and reach the hair cuticle layers. The melanosomes then adhere to the cuticle layers; however, and a portion of them continue penetrating the hair, finally entering the hair cortex where they become regular melanin granules. However, white hair roots are not formed in this manner as contain little melanosomes and melanin granules. The types of cuticle layers formed in both white and black hair roots include the curved board, mass and cogwheel types. Key words: Morphogenetic type, white and black hairs, hair root, melanin granules, cuticles.