What is the main function of the hair cuticle?

The primary function of the hair cuticle is to protect the hair shaft. It consists of overlapping, scale-like cells that form a protective outer layer around the hair. The cuticle plays a crucial role in maintaining the integrity and health of the hair by shielding it from environmental damage, such as UV rays and chemical exposure, as well as mechanical stress.

When considering the other options, the cuticle does contribute to the overall strength and resilience of the hair shaft, but its main role is not to provide structural support directly. Therefore, while protection is a major function of the cuticle, the option focusing on its role in holding the hair in the follicle is not accurate, as that function is primarily attributed to other parts of the hair structure, such as the hair bulb and the surrounding dermal papilla. Nourishment is delivered to the hair through the bloodstream and is not a role played by the cuticle itself. Thus, understanding the role of the hair cuticle helps clarify why protection is considered its main function.