Kansas Cosmetology Practice Exam 2025 - Free Cosmetology Practice Questions and Study Guide

The primary function of the sebaceous glands is to produce sebum, an oily substance that plays a vital role in lubricating the skin and hair. Sebum helps maintain skin hydration, provides a barrier against environmental factors, and possesses antibacterial properties that can protect the skin from infections. The presence of sebum on the skin surface creates a natural moisturizer, which is particularly important in preventing dryness and maintaining skin health.

In contrast, the other options reference functions carried out by different systems or glands in the body. Regulating body temperature is mainly the role of the sweat glands and the circulatory system, while perspiration is specifically produced by the sweat glands to cool the body. Hair growth is influenced by various factors including hormones and follicle activity, rather than being a direct function of sebaceous glands. Thus, the role of sebum production distinctly highlights the primary function of sebaceous glands in skin maintenance and protection.