par Gilaberte-Calzada, Yolanda;Prieto-Torres, Lucía;Pastushenko, Ievgenia 
;Juarranz, Angeles
Référence Nanoscience in Dermatology, Elsevier Inc., page (1-14)
Publication Publié, 2016-08
;Juarranz, AngelesRéférence Nanoscience in Dermatology, Elsevier Inc., page (1-14)
Publication Publié, 2016-08
Partie d'ouvrage collectif
| Résumé : | The skin is the largest human organ. It has three layers: the epidermis, the dermis, and the hypodermis. The epidermis is the outer layer, formed by a stratified, squamous epithelium composed mainly of keratinocytes and also dendritic cells (melanocytes, Merkel cells, and Langerhans cells). The epidermis is divided into four layers according to keratinocyte morphology and the degree of differentiation into cornified cells (the outermost layer is called the stratum corneum). The dermis is the middle layer basically made up of collagen and amorphous connective tissue containing nerve and vascular networks, epidermal appendages, fibroblasts, macrophages, and mast cells. The hypodermis or subcutaneous tissue is a real endocrine organ composed of lobules of adipocytes separated by fibrous septa formed from collagen and blood vessels. The skin and its various components have the ability to communicate with other tissues and to self-regulate through the production of cytokines, neurotransmitters, hormones, and their corresponding receptors. These neuro-immuno-endocrine functions are tightly networked to central regulatory systems. The skin is also a vast reserve of stem cells to rejuvenate the body surface and repair wounds. All of these structures allow the skin to perform vital functions, including protection against physical, chemical, and biological agents; prevention of excess water loss; and regulation of temperature. In addition, the skin constitutes the sensory organ for touch and environmental sensing. |
