BIOL 2224 Lecture Notes - Lecture 3: Stratum Spinosum, Stratum Granulosum, Stratum Basale
Document Summary
Epidermis- the epithelium of the integument is the epidermis. Stratum basale- the deepest epidermal layer and is also known as the stratum germinativum or basal layer. Single layer of cuboidal to low columnar cells is tightly attached by hemidesmosomes to an underlying basement membrane that separates the epidermis from the connective tissue of the dermis. Three types of cells occupy the stratum basale: keratinocytes- are the most abundant cell type in the epidermis and are found throughout all epidermal strata. The stratum basale is dominated by large keratinocyte stem cells, which divide to generate new keratinocytes that replace dead keratinocytes shed from the surface. The name comes from keratin, a protein that strengthens the epidermis considerably. The keratin proteins found in keratinocytes are called cytokeratins. The structure gives skin its strength and makes the epidermis water resistant: melanocytes- have long, branching processes and are scattered amount he keratinocytes of the stratum basale.
