Hairs are threads of fused (i.e. attached together), dead, keratinized cells.
The hair root is the part of the hair below the surface of the skin. It is therefore the part of the hair that includes or interacts with associated structures in the dermis and hypodermis layers of skin.
To explain the definition of a hair root by comparision with the rest of the structure of a hair, note that, structurally, hairs consist of two main parts:
- The hair shaft is the visible part of the hair that protrudes through the skin. It consists of three layers that are also along the hair through the hair root as well. (They are the medulla, the cortex and the cuticle.)
- The hair root is the part of the hair below the surface of the skin that includes and/or interacts with many other associated structures within the dermis and hypodermis layers of skin.
The topic of the structure of a hair follicle is included in some courses in health sciences, including subjects such as nursing, skin care, hair care, beauty therapy and various holistic therapies.