Written Laser Hair Removal Practice Exam

What primary role does vellus hair play in the integumentary system?

1. Protecting deeper skin layers from infection

2. Facilitating the evaporation of perspiration

3. Acting as a barrier to chemical substances

4. Producing sebum for skin and hair lubrication

The correct answer is: Facilitating the evaporation of perspiration

Vellus hair serves several functions in the integumentary system, but one important role it plays is related to thermoregulation and the evaporation of perspiration. Vellus hair is fine, short, and light hair that covers most of the body, and it helps to increase the surface area for the evaporation of sweat. When sweat evaporates from the skin's surface, it aids in regulating body temperature, especially during physical activities or in hot environments. While other options may describe functions of different skin structures or hair types, they do not accurately represent the primary role of vellus hair within the integumentary system. For example, protecting deeper skin layers from infection, acting as a barrier to chemical substances, or producing sebum are functions related more to other components of the skin, such as the dermis, sebaceous glands, or coarser terminal hair, rather than vellus hair itself. Thus, associating vellus hair predominantly with the facilitation of perspiration evaporation reflects its unique contribution to the body's thermoregulatory processes.