What are small granules filled with melanin called?

Small granules filled with melanin are known as melanosomes. These organelles play a crucial role in the production and storage of melanin, which is the pigment responsible for the coloration of skin, hair, and eyes. Melanosomes are produced by melanocytes, the cells that generate melanin and are found in the epidermis.

Keratinocytes are skin cells primarily responsible for forming the outermost layer of the skin and do not contain melanin granules. Desmosomes are structures that help cells adhere to one another, providing strength and stability to tissues, but they do not relate to melanin or pigmentation. Fibroblasts are cells that generate connective tissue and collagen in the skin, which does not involve melanin production. Thus, melanosomes being the specific granules filled with melanin makes this answer accurate in the context of skin pigmentation and cellular biology.