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         DERECHOS RESERVADOS
Text Box: Melanins Part IV

FEATHER SHEATH

Disintegrates after the feather emerges

        MELANOSOMES

Pigment granules synthesized and transported by the melanocyte

RACHIS

         DENDRITES

Melanocyte prolongation that connects and transports melanosomes to the queratocytes

       MELANOCYTE

Cell that produces and transports melanosomes

         PAPILLA

Specialized germinal cell that produces the feather

BARBS

EPIDERMIS

DERMIS

SHAFT

 QUERATOCYTES

Queratin producing cell
Text Box: After migration of the melanoblasts, they will differentiate into malanocytes and will become associated with the feather germ to accomplish the pigmentation process of feathers, skin, eyes and horny areas. The enzyme that triggers the biosynthesis action is tyrosine. The melanocytes are activated by melanotropine and the melanosome synthesis process is initiated. The melanosomes travel through the melanocyte’s dendrites until they reach the keratinocyte where the pigments are transferred to the feather parts. The colour that will eventually be produced will depend on the evolution of one or more of the following events, subjected and controlled by the specific mutation. Migration of the melanoblasts Capability of differentiation into melanocytes Capability of synthesis and melanization of the melanosomes Size and shape and distribution of melanosomes Ease of transference of the melanosomes within the queratocytes Synthesis, inhibition and deterioration of tyrosine Degree of activity of tyrosine in the melanosomes Some cause and effect examples are: The pattern of melanoblast migration: will determine the variegation pattern Amount of synthesis or inhibition of tyrosine: partial or full albinism Size shape and distribution of the melanosomes: determines melanin expression and coloration Capability of transference of the melanosomes into the queratocytes: caused by the dilution factor that inhibits the development of dendrites and interferes with the mealnization process.

 M S H (Melanotropine)

Hormone produced by the  pituitary gland which  stimulates the melanin production

BARBULES