Certified Wound Ostomy Nurse (CWON) Practice Test 2025 - Free CWON Practice Questions and Study Guide

The primary function of the stratum corneum, which is the outermost layer of the epidermis, is keratinization. This process involves the formation of a tough, protective layer composed mainly of dead skin cells that are rich in keratin, a fibrous protein that helps to protect underlying tissues from environmental damage, pathogens, and water loss. The keratinization process leads to the gradual shedding and replacement of the stratum corneum, ensuring that the skin remains resilient and capable of serving as a barrier.

Additionally, while the stratum corneum does play a role in water retention through its lipid content and structural integrity, the essential function that defines it is its role in keratinization. This process is vital for maintaining the skin's protective barrier and ensuring its overall health and function.