Search results
Results From The WOW.Com Content Network
[5] [better source needed] The average human skin cell is about 30 μm in diameter, but there are variants. A skin cell usually ranges from 25 to 40 μm 2, depending on a variety of factors. Skin is composed of three primary layers: the epidermis, the dermis and the hypodermis. [4]
The skin acts as a barrier, a kind of sheath, made of several layers of cells and their related glands. The skin is a dynamic organ that contains different cells which contains elements of the innate and the adaptive immune systems which are activated when the tissue is under attack by invading pathogens.
This complex surrounds cells in the stratum corneum and contributes to the skin's barrier function. Corneodesmosomes (modified desmosomes) facilitate cellular adhesion by linking adjacent cells within this epidermal layer. These complexes are degraded by proteases, eventually permitting cells to be shed at the surface. Desquamation and ...
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. [1] The epidermal layer provides a barrier to infection from environmental pathogens [2] and regulates the amount of water released from the body into the atmosphere through transepidermal water loss.
Sebaceous glands secrete the skin lubricant sebum. Sebum is secreted onto the hair shaft and it prevents the hair from splitting. It consists mostly of lipids. After the sebum spreads along and up the hair shaft, it is distributed over the skin surface where it lubricates and waterproofs the outer layer of the skin, the stratum corneum. [1] [2]
The basal layer is a stem cell layer and through asymmetrical divisions, becomes the source of skin cells throughout life. It is maintained as a stem cell layer through an autocrine signal, TGF alpha , and through paracrine signaling from FGF7 ( keratinocyte growth factor ) produced by the dermis below the basal cells.
Micrograph of keratinocytes, basal cells and melanocytes in the epidermis Keratinocytes (stained green) in the skin of a mouse. Keratinocytes are the primary type of cell found in the epidermis, the outermost layer of the skin. In humans, they constitute 90% of epidermal skin cells. [1]
Dermal fibroblasts are cells within the dermis layer of skin which are responsible for generating connective tissue and allowing the skin to recover from injury. [1] Using organelles (particularly the rough endoplasmic reticulum), dermal fibroblasts generate and maintain the connective tissue which unites separate cell layers. [2]