Which of the following is NOT one of the layers of the epidermis?

The epidermis is the outermost layer of the skin and is composed of several distinct layers, which are categorized based on their characteristics and functions. The main layers of the epidermis include the stratum corneum, stratum lucidum (found only in certain thick skin areas), stratum granulosum, stratum spinosum, and stratum basale.

The dermis, on the other hand, is not a layer of the epidermis. Instead, it is the layer of skin located beneath the epidermis. The dermis contains connective tissue, blood vessels, nerve endings, and various skin appendages, such as hair follicles and sweat glands. Its role is critical for supporting and nourishing the epidermis as well as providing strength and elasticity to the skin.

In contrast, the layers of the epidermis, such as the corneum, lucidum, and granulosum, serve various functions related to protection and the regulation of skin hydration and permeability. Therefore, identifying that the dermis does not belong to the epidermal layers is key in understanding the structure of the skin.