Wyoming State Board Cosmetology Practice Exam 2025 - Free Cosmetology Exam Questions and Study Guide

The hair shaft is the part of the hair that consists of dead cells. It is the visible portion of the hair that extends above the skin's surface. The hair shaft is primarily composed of a protein called keratin, which provides structure and strength. As the hair grows, new cells are generated in the hair follicle, pushing the older, dead cells outward, where they form the shaft. This is why the hair shaft does not require blood supply or nutrients; it is essentially a column of keratinized cells that have completed their lifecycle and serve to protect the underlying structures of the hair.

In contrast, the hair follicle is living tissue that contains cells actively involved in hair growth, while the hair root, located beneath the surface of the skin, is where the hair originates and continues to receive nourishment. The hair cuticle refers to the outermost layer of the hair shaft itself; although it contributes to the overall health of the hair by providing a protective barrier, it is also made of dead cells that protect the inner structures. Therefore, while the cuticle is a part of the hair shaft, the answer specifically focuses on the overall composition of the hair shaft as an entity where dead cells predominate.