This type of muscle is striated, involuntary, with one centrally located nucleus.

A. corneum:The stratum corneum is the outermost layer of the epidermis composed of fully keratinized, dead cells. These cells provide protection but are incapable of undergoing mitosis.

B. lucidum:The stratum lucidum is a clear layer found only in thick skin, such as the palms and soles. It consists of dead keratinocytes that have lost their nuclei, so mitosis does not occur here.

C. granulosum:The stratum granulosum contains keratinocytes that are beginning to die and fill with keratohyalin granules. Mitosis does not take place in this layer, as cells are transitioning to terminal differentiation.

D. basale:The stratum basale is the deepest layer of the epidermis where keratinocyte stem cells actively divide. Continuous mitosis in this layer replenishes the epidermis and pushes new cells toward the surface.

E. spinosum:The stratum spinosum provides strength and flexibility with its desmosomal attachments. While cells here may appear metabolically active, true mitotic activity primarily occurs in the stratum basale below it.

A. reticular layer:The reticular layer is the deeper part of the dermis, composed mainly of dense irregular connective tissue. It provides strength, elasticity, and houses structures such as glands, nerves, and blood vessels, making it part of the skin.

B. hypodermis:The hypodermis, also known as the subcutaneous layer, lies beneath the dermis and is made up of adipose and connective tissue. It anchors the skin to underlying structures but is not technically considered part of the skin itself.

C. dermis:The dermis is one of the two main layers of the skin, lying beneath the epidermis. It contains connective tissue, blood vessels, and sensory receptors that support and nourish the epidermis.

D. epidermis:The epidermis is the outermost layer of the skin made of keratinized stratified squamous epithelium. It provides a protective barrier against environmental damage, pathogens, and water loss.