Thestratum basale (basal layer, sometimes referred to asstratum germinativum) is the deepest layer of the five layers of theepidermis, the external covering ofskin inmammals.
The stratum basale is a single layer ofcolumnar or cuboidalbasal cells. The cells are attached to each other and to the overlyingstratum spinosum cells bydesmosomes andhemidesmosomes. Thenucleus is large, ovoid and occupies most of the cell. Some basal cells can act likestem cells with the ability to divide and produce new cells, and these are sometimes called basalkeratinocyte stem cells. Others serve to anchor the epidermisglabrous skin (hairless), and hyper-proliferative epidermis (from a skin disease).[1]
They divide to form the keratinocytes of thestratum spinosum, which migrate superficially.[2] Other types of cells found within the stratum basale aremelanocytes (pigment-producing cells) andMerkel cells (touch receptors).
Basal-cell carcinomas (basal-cell cancers), account for around 80 per cent of allskin cancers.[3] Not all basal-cell cancers originate in the basal cells but they are so named because the cancer cells resemble basal cells when seen under a microscope.[4]
In a growing fetus,fingerprints form where the cells of the stratum basale meet the papillae of the underlying papillary layer of thedermis, resulting in the formation of the ridges on the fingers. Fingerprints are unique to each individual and are used for forensic analyses because the patterns do not change with the growth and aging processes.[5]
This article incorporatestext available under theCC BY 4.0 license.Betts, J Gordon; Desaix, Peter; Johnson, Eddie; Johnson, Jody E; Korol, Oksana; Kruse, Dean; Poe, Brandon; Wise, James; Womble, Mark D; Young, Kelly A (June 28, 2023).Anatomy & Physiology. Houston: OpenStax CNX. 5.1 Layers of the skin.ISBN 978-1-947172-04-3.