Epidermis (OpenStax Anatomy and Physiology)
The epidermis is composed of keratinized, stratified squamous epithelium. It is made of four or five layers of epithelial cells, depending on its location in the body. It does not have any blood vessels within it (i.e., it is avascular). Skin that has four layers of cells is referred to as “thin skin.” From deep to superficial, these layers are the stratum basale, stratum spinosum, stratum granulosum, and stratum corneum. Most of the skin can be classified as thin skin. “Thick skin” is found only on the palms of the hands and the soles of the feet. It has a fifth layer, called the stratum lucidum, located between the stratum corneum and the stratum granulosum.
The cells in all of the layers except the stratum basale are called keratinocytes. A keratinocyte is a cell that manufactures and stores the protein keratin. Keratin is an intracellular fibrous protein that gives hair, nails, and skin their hardness and water-resistant properties.
Related Research: Multiscale modeling of layer formation in epidermis
Betts, J. G., Young, K. A., Wise, J. A., Johnson, E., Poe, B., Kruse, D. H., … DeSaix, P. (n.d.). Anatomy and Physiology. Houston, Texas: OpenStax. Access for free at: https://openstax.org/details/books/anatomy-and-physiology
Other Related Research
Date Published: March 20, 2013 Publisher: Public Library of Science Author(s): Magdalena Banas, Katarzyna Zabieglo, Gopinath Kasetty, Monika Kapinska-Mrowiecka, Julia Borowczyk, Justyna Drukala, Krzysztof Murzyn, Brian A. Zabel, Eugene C. Butcher, Jens M. Schroeder, Artur Schmidtchen, Joanna Cichy, Markus M. Heimesaat. http://doi.org/10.1371/journal.pone.0058709 Abstract: Chemerin, a chemoattractant ligand for chemokine-like receptor 1 (CMKLR1) is predicted to share … Continue reading
Date Published: January 6, 2014 Publisher: Public Library of Science Author(s): Raymond T. H. Lee, P. V. Asharani, Thomas J. Carney, Ben Hogan. http://doi.org/10.1371/journal.pone.0084858 Abstract: The epidermis of terrestrial vertebrates is a stratified epithelium and forms an essential protective barrier. It is continually renewed, with dead corneocytes shed from the surface and replaced from a … Continue reading