Which of the following statements is true regarding the cellular structure of the skin?

The correct statement regarding the cellular structure of the skin is that the stratum granulosum contains keratinocytes. The stratum granulosum is a layer of the epidermis, located between the stratum lucidum (in thick skin) or stratum corneum (in thinner skin) and the stratum spinosum. In this layer, keratinocytes are in the process of keratinization, where they begin to produce keratin, a crucial protein that helps protect the skin and underlying tissues, and contributes to the waterproof barrier of the skin.

Keratinocytes in the stratum granulosum undergo a transformation that includes the flattening of their cells and an increase in keratin deposition. This process is essential for maintaining the integrity and function of the skin, making the stratum granulosum a critical component of the epidermis.

The other statements do not accurately reflect the cellular structure of the skin. The dermis, contrary to the first statement, contains a rich supply of blood vessels that play a significant role in thermoregulation and nutrient supply. The epidermis is primarily composed of keratinocytes, not muscle cells, which makes the claim about muscle cells incorrect. Lastly, the hypodermis, also known