![]() ![]() Keratohyalin granules contain keratin precursors that eventually aggregate, crosslink, and form bundles. Stratum granulosum, 3-5 cell layers, contains diamond shaped cells with keratohyalin granules and lamellar granules. Dendritic cells can be found in this layer. Stratum spinosum, 8-10 cell layers, also known as the prickle cell layer contains irregular, polyhedral cells with cytoplasmic processes, sometimes called “spines”, that extend outward and contact neighboring cells by desmosomes. The cells found in this layer are cuboidal to columnar mitotically active stem cells that are constantly producing keratinocytes. Stratum basale, also known as stratum germinativum, is the deepest layer, separated from the dermis by the basement membrane (basal lamina) and attached to the basement membrane by hemidesmosomes. The layers of the epidermis include the stratum basale (the deepest portion of the epidermis), stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum (the most superficial portion of the epidermis). The upper back is considered thickest based on the thickness of the dermis, but it is considered “thin skin” histologically because the epidermal thickness lacks the stratum lucidum layer and is thinner than hairless skin. Hairless skin found in the palms of the hands and soles of the feet is thickest because the epidermis contains an extra layer, the stratum lucidum. The thickness of each layer of the skin varies depending on body region and categorized based on the thickness of the epidermal and dermal layers. This article discusses the relevant anatomical structures of the skin’s epidermal layer, its structure, function, embryology, vascular supply, innervation, surgical considerations, and clinical relevance. It also regulates temperature and the amount of water released into the environment. The skin's structure is made up of an intricate network which serves as the body’s initial barrier against pathogens, UV light, and chemicals, and mechanical injury. It is made up of three layers, the epidermis, dermis, and the hypodermis, all three of which vary significantly in their anatomy and function. The Epidermis is made up of five cell layers, which have different functions: Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum.Skin is the largest organ in the body and covers the body's entire external surface. location of melanocytes and tactile epithelial cells.Ĭomposed of a plane stratified keratinized epithelium that constantly grows and maintains a normal thickness by the process of peeling. These are not randomly oriented but forming the regular skin tightening lines known as Langer lines. It is characterized by it´s thick, irregular bundles of collagen fibers and elastic fibers. The inner and thicker layer of the dermis. It´s surface forms papilla that increases the mechanical union between dermis and epidermis. It has conjunctive tissues and blood vessels that nourish the skin and helps to control the temperature. This stratum is a thin superior layer in the dermis. dermal layer responsible for fingerprints. The former associated with nerve fibers, transmit part of the touch, and the latter, form the pigment responsible for skin coloring and tanning, melanin.į. In this basal layer, there are also Merkel cells as well as melanocytes. These cells are the precursor of keratinocytes, this is why this layer is also called germinativum. Stratum basale is the innermost germinative, single, basal layer of the epidermis composed of basal cuboidal-shaped cells. location of melanocytes and tactile epithelial cells. epidermal layer exhibiting the most rapid cell division.ħ. It also produces a glycoprotein that helps to prevent water loss.Ī. This stratus is also known as "Malpigio stratum". These cells are rich in DNA necessary for proteinic synthesis that ends in keratin production, and Langerhans cells that belong to the immunity system. layer that secretes a glycolipid that prevents water loss from the skin.Ĩ to 10 irregular cell layers. ![]() This is also the layer where it begins keratinization.Į. This is why they show high lysosomes enzymes concentration. These cells are arranged in two to four layers, and they begin to degenerate. These layer cells contain granules filled with keratohyalin that is needed for keratin production. layer named for the numerous granules present. They lack a nucleus and the cytoplasm is filled with a gelatinous substance, eleidin, which will transform into keratin.ī. Keratinocytes are diaphanous and are grouped together. This layer is so thin that the cells´ edges and some ties their nucleus can not be identified. layer of translucent cells in thick skin containing dead keratinocytesĪlso known as the transparent layer, is only located in the thicker parts of the skin, such as the hands´ palms and the feets´ soles. ![]()
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