The ''stratum basale'' (basal layer, sometimes referred to as ''stratum germinativum'') is the deepest layer of the five layers of the

epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water rel ...

, the external covering of

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...

s. The ''stratum basale'' is a single layer of columnar or cuboidal basal cells. The cells are attached to each other and to the overlying stratum spinosum cells by desmosomes and hemidesmosomes. The

nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: * Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucl ...

is large, ovoid and occupies most of the cell. Some basal cells can act like

stem cell In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can differentiate into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type of ...

s with the ability to divide and produce new cells, and these are sometimes called basal keratinocyte stem cells. Others serve to anchor the epidermis

glabrous skin Glabrousness (from the Latin '' glaber'' meaning "bald", "hairless", "shaved", "smooth") is the technical term for a lack of hair, down, setae, trichomes or other such covering. A glabrous surface may be a natural characteristic of all or part o ...

(hairless), and hyper-proliferative epidermis (from a skin disease).McGrath, J.A.; Eady, R.A.; Pope, F.M. (2004). ''Rook's Textbook of Dermatology'' (Seventh Edition). Blackwell Publishing. Pages 3.7. . They divide to form the keratinocytes of the stratum spinosum, which migrate superficially. Other types of cells found within the ''stratum basale'' are

melanocyte Melanocytes are melanin-producing neural crest-derived cells located in the bottom layer (the stratum basale) of the skin's epidermis, the middle layer of the eye (the uvea), the inner ear, vaginal epithelium, meninges, bones, and hear ...

s (pigment-producing cells) and

Merkel cell Merkel cells, also known as Merkel-Ranvier cells or tactile epithelial cells, are oval-shaped mechanoreceptors essential for light touch sensation and found in the skin of vertebrates. They are abundant in highly sensitive skin like that of the f ...

s (touch receptors).

Clinical significance

Basal-cell cancer Basal-cell carcinoma (BCC), also known as basal-cell cancer, is the most common type of skin cancer. It often appears as a painless raised area of skin, which may be shiny with small blood vessels running over it. It may also present as a raise ...

s, also called basal-cell carcinomas, account for around 80 per cent of all

skin cancer Skin cancers are cancers that arise from the skin. They are due to the development of abnormal cells that have the ability to invade or spread to other parts of the body. There are three main types of skin cancers: basal-cell skin cancer (BCC) ...

s. 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.

Additional images

Image:Normal Epidermis and Dermis with Intradermal Nevus 10x.JPG, Epidermis and dermis of human skin Image:Skinlayers.png, Section of epidermis

References

{{Integumentary system Skin anatomy Epithelial cells

Clinical significance

Additional images

See also

References