Arkansas Esthetician Practice Exam

What is the epidermis primarily composed of?

1. Melanocytes

2. Sweat glands

3. Keratinocytes, which consist of keratin

4. Mast cells

The correct answer is: Keratinocytes, which consist of keratin

The epidermis is primarily composed of keratinocytes, which are specialized cells responsible for producing keratin, a protein that provides structural integrity and protection to the skin. Keratinocytes make up the majority of the epidermis and play a crucial role in the skin's barrier function, helping to prevent water loss and protect against environmental damage. While melanocytes, sweat glands, and mast cells are important components of the skin, they do not dominate the composition of the epidermis like keratinocytes do. Melanocytes are responsible for producing melanin, which gives skin its color and protects against UV radiation, but they are present in much lower numbers compared to keratinocytes. Sweat glands are not part of the epidermis; they are located in the dermis beneath the epidermis. Mast cells, which are involved in immune responses and allergic reactions, are also found deeper in the skin rather than in the epidermis itself. Therefore, keratinocytes represent the primary cell type in the epidermis, making this option the correct choice.