Which layers make up the hair shaft?

The hair shaft consists of three layers: the medulla, cortex, and cuticle.

The medulla is the innermost layer of the hair, which can be present in some hair types and is typically softer and more airy. The cortex is the middle layer, composed of tightly packed cells and responsible for the strength, color, and texture of the hair. It makes up the bulk of the hair shaft and contains the majority of the pigment granules that give hair its color. Finally, the cuticle is the outermost layer, made up of overlapping, scale-like cells. It serves as a protective barrier, helping to shield the inner layers from damage and environmental factors.

This layered structure is critical for the overall health and aesthetic of the hair, influencing everything from shine to durability. Understanding these components is essential for anyone studying hair biology or involved in hair care or cosmetic industries. The other options focus on different skin structures or components unrelated to the hair shaft itself.