What protein forms the pink layer atop the epithelium of the skin?

Study for the CAMLPR Histology Practice Test. Study with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

Keratin is the protein that forms the keratinized outer layer of the epidermis. The topmost layer, the stratum corneum, consists of dead cells filled with keratin (corneocytes); this keratin-rich layer is what gives it a pink, eosinophilic appearance under routine staining. Melanin is pigment in melanocytes located deeper in the epidermis, elastin is in elastic fibers of the dermis, and collagen is the main protein in dermal connective tissue. Thus, the pink layer atop the epithelium is due to keratin.