Keratin

Definition

Keratin is a tough, fibrous protein that forms the primary structural component of hair, nails, and the outer layer of skin. It provides protection against abrasion and water loss.

Related terms

Epidermis:

The outermost layer of skin that contains keratinized cells to protect the body against external environment.

Hair follicle: A small tubular cavity containing the root of a hair, in which keratin is produced to form hair.

Nail bed: The skin beneath the nail plate that contains nerves and blood vessels; it supports the nail plate as it grows and is protected by keratin