Which epidermal layer is the granular layer with keratin-filled cells?

Which epidermal layer is the granular layer with keratin-filled cells?

• A. Stratum corneum
• B. Stratum spinosum
• C. Stratum granulosum
• D. Stratum basale

Answer: (C)

In the epidermis, the granular layer is the stratum granulosum. This layer is where keratinocytes accumulate keratin as they begin keratinization, and keratohyalin granules appear in the cytoplasm, giving the cells a granular look. These changes mark the transition from living, dividing cells in the deeper layers to the dead, keratin-filled cells of the outermost stratum corneum. The deeper basal layer contains proliferating cells, the spiny layer still has viable cells connected by desmosomes, and the outermost layer is composed of flattened, dead keratinocytes ready to shed.

In the epidermis, the granular layer is the stratum granulosum. This layer is where keratinocytes accumulate keratin as they begin keratinization, and keratohyalin granules appear in the cytoplasm, giving the cells a granular look. These changes mark the transition from living, dividing cells in the deeper layers to the dead, keratin-filled cells of the outermost stratum corneum. The deeper basal layer contains proliferating cells, the spiny layer still has viable cells connected by desmosomes, and the outermost layer is composed of flattened, dead keratinocytes ready to shed.