Search results
Results From The WOW.Com Content Network
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 developmental origin , structure and chemical composition .
Some skin secretions are associated with body hair. Skin secretions originate from glands that in dermal layer of the epidermis. Sweat, a physiological aid to body temperature regulation, is secreted by eccrine glands. Sebaceous glands secrete the skin lubricant sebum. Sebum is secreted onto the hair shaft and it prevents the hair from splitting.
The skin is an epithelial membrane also called the cutaneous membrane. It is a stratified squamous epithelial membrane resting on top of connective tissue. The apical surface of this membrane is exposed to the external environment and is covered with dead, keratinized cells that help protect the body from desiccation and pathogens.
Skin plays an important immunity role in protecting the body against pathogens and excessive water loss. Its other functions are insulation, temperature regulation, sensation, synthesis of vitamin D, and the protection of vitamin B folates. Severely damaged skin will try to heal by forming scar tissue. This is often discoloured and depigmented.
The skin is one of the largest organs of the body. In humans, it accounts for about 12 to 15 percent of total body weight and covers 1.5 to 2 m 2 of surface area. [1] 3D still showing human integumentary system. The skin (integument) is a composite organ, made up of at least two major layers of tissue: the epidermis and the dermis. [2]
Most of the barrier functions of the epidermis localize to this layer. [12] clear/translucent layer (stratum lucidum, only in palms and soles) This narrow layer is found only on the palms and soles. The epidermis of these two areas is known as "thick skin" because with this extra layer, the skin has 5 epidermal layers instead of 4.
The subcutaneous tissue (from Latin subcutaneous 'beneath the skin'), also called the hypodermis, hypoderm (from Greek 'beneath the skin'), subcutis, or superficial fascia, [2] is the lowermost layer of the integumentary system in vertebrates. [3] The types of cells found in the layer are fibroblasts, adipose cells, and macrophages.
A number of structural proteins (filaggrin, keratin), enzymes (e.g. proteases), lipids, and antimicrobial peptides contribute to maintain the important barrier function of the skin. Keratinization is part of the physical barrier formation ( cornification ), in which the keratinocytes produce more and more keratin and undergo terminal ...