Stratum corneum
| Stratum corneum | |
|---|---|
Histologic image of human epidermis in thick skin | |
| Details | |
| Precursor | Ectoderm |
| Part of | Skin |
| System | Integumentary |
| Identifiers | |
| Latin | stratum corneum epidermidis |
| Anatomical terminology | |
The stratum corneum (Latin for 'horny layer') is the outermost layer of the epidermis of the skin. Consisting of dead tissue, it protects underlying tissue from infection, dehydration, chemicals, and mechanical stress. It is composed of 15 to 20 layers of flattened cells with no nuclei or cell organelles.
Among its properties are mechanical shear, impact resistance, water flux and hydration regulation, microbial proliferation and invasion regulation, initiation of inflammation through cytokine activation and dendritic cell activity, and selective permeability to exclude toxins, irritants, and allergens.[2] The cytoplasm of corneocytes, its cells, shows filamentous keratin. These corneocytes are embedded in a lipid matrix composed of ceramides, cholesterol, and fatty acids.[3]
Desquamation is the process of cell shedding from the surface of the stratum corneum, balancing proliferating keratinocytes that form in the stratum basale. These cells migrate through the epidermis towards the surface in a journey that takes approximately fourteen days.[4]
- ^ Sadowski T, Klose C, Gerl MJ, Wójcik-Maciejewicz A, Herzog R, Simons K, Reich A, Surma MA (2017). "Large-scale human skin lipidomics by quantitative, high-throughput shotgun mass spectrometry". Scientific Reports. 7: 43761. Bibcode:2017NatSR...743761S. doi:10.1038/srep43761. PMC 5339821. PMID 28266621.
- ^ Del Rosso, James Q.; Levin, Jacqueline (2011). "The Clinical Relevance of Maintaining the Functional Integrity of the Stratum Corneum in both Healthy and Disease-affected Skin". The Journal of Clinical and Aesthetic Dermatology. 4 (9): 22–42. ISSN 1941-2789. PMC 3175800. PMID 21938268.
- ^ Mitra, Ashim K.; Kwatra, Deep; Vadlapudi, Aswani Dutt (2015). Drug Delivery. Burlington, MA: Jones & Bartlett Learning. pp. 285–286. ISBN 978-1-284-02568-2.
- ^ Ovaere P; Lippens S; Vandenabeele P; Declercq W. (2009). "The emerging roles of serine protease cascades in the epidermis". Trends in Biochemical Sciences. 34 (9): 453–463. doi:10.1016/j.tibs.2009.08.001. PMID 19726197.