Keratinocytes: Ninety-five percent of the epidermis is composed of keratinocytes. The major function of these cells is the production of keratin, a tough protein that helps protect the skin from UV light, heat, and water loss.
Melanocytes: Melanocytes are cells that produce melanin, the skin’s pigment. Melanocytes are located in the basal layer of the epidermis.
Langerhans cells: Langerhans cells are a type of dendritic cell. Dendritic cells are immune cells that process foreign materials, called antigens, and present the antigens to other immune system cells. Langerhans cells are found in the stratum spinosum of the epidermis, where they act as part of the skin’s defense against infection.
Adipocytes: Adipocytes are fat-storing cells, not specialized skin cells. However, adipocytes are an important component of the subcutaneous layer. They insulate the body from cold, help absorb trauma to the skin and cushion deeper tissues, and act as storage vessels for the body’s reserve fuel.
Collagen: Collagen is a protein that is the principal constituent of white fibrous connective tissue. Collagen is an integral component of skin, as well as an important protein in tendons, bone, cartilage, and ligaments. Collagen helps hold the skin together and gives the skin its firmness and elasticity. Certain cosmetic laser treatments are intended to stimulate collagen production, and collagen injections may be used to rejuvenate sagging or wrinkled skin.
Elastin: As its name suggests, elastin helps give skin its elasticity. Elastin is a protein found in skin and other connective tissue that allows tissues to resume their shape after stretching or contracting. Elastin begins to degrade with age. Avoiding skin-damaging factors like cigarette smoke, stress, and UV light can help prevent premature skin aging and elastin breakdown.
Keratin: Keratin is a tough, insoluble fibrous protein that forms hair and nails. Keratin is also a major component of the stratum corneum, the top layer of the epidermis. Keratin gives skin its strength, waterproofs the skin surface, and helps protect the skin against heat and UV light.