query: the two main layers of the epidermis of the skin are the

pos: Epidermis Epidermis The epidermis is the outermost of the three layers that make up 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 released from the body into the atmosphere through transepidermal water loss. The epidermis is composed of multiple layers of flattened cells that overlie a base layer (stratum basale) composed of columnar cells arranged perpendicularly. The rows of cells develop from stem cells in the basal layer. Cellular mechanisms for regulating water and sodium levels (ENaCs) are found in all layers

pos: Epidermolysis bullosa collagen (collagen VII). DEB-causing mutations can be either autosomal dominant or autosomal recessive. Epidermis bullosa pruriginosa and Albopapuloid epidermolysis bullosa (Pasini's disease) are rare subtypes of this disease. The human skin consists of two layers: an outermost layer called the epidermis and a layer underneath called the dermis. In individuals with healthy skin, there are protein anchors between these two layers that prevent them from moving independently from one another (shearing). In people born with EB, the two skin layers lack the protein anchors that hold them together, resulting in extremely fragile skin—even minor mechanical friction (like rubbing or pressure)

pos: Human skin underlying basal lamina. The epidermis contains no blood vessels, and cells in the deepest layers are nourished almost exclusively by diffused oxygen from the surrounding air and to a far lesser degree by blood capillaries extending to the outer layers of the dermis. The main type of cells which make up the epidermis are Merkel cells, keratinocytes, with melanocytes and Langerhans cells also present. The epidermis can be further subdivided into the following "strata" (beginning with the outermost layer): corneum, lucidum (only in palms of hands and bottoms of feet), granulosum, spinosum, basale. Cells are formed through mitosis at the

pos: Role of skin in locomotion and intact during flight. Bats rely on skin on their wings to generate lift and thrust used in flight. Therefore, the structure of the bat wing skin is different from the skin of the bat body. Bat wing skin consists of two thin layers of epidermis with a thin layer of dermis/hypodermis located between the epidermal layers whereas the skin of the bat body consists of a single layer of epidermis with a thicker layer of dermis internal to the epidermis. Within the dermal and epidermal layer of bat wing skin, the connective tissue and muscle fibers provide the structural

pos: Flap (surgery) into three main layers including the epidermis, the dermis, and the subcutaneous tissue. Blood is supplied to the skin mainly by two networks of blood vessels. The deep network lies between the dermis and the subcutaneous tissue, while the shallow network lies within the papillary layer of the dermis. The epidermis is supplied by diffusion from this shallow network and both networks are supplied by collaterals, and by perforating arteries that bring blood from deeper layers either between muscles (septocutaneous perforators) or through muscles (musculocutaneous perforators). This redundant and robust blood supply is important in flap surgery because part of

pos: Skin condition yellow). The diagnosis of many conditions often also requires a skin biopsy which yields histologic information that can be correlated with the clinical presentation and any laboratory data. The introduction of cutaneous ultrasound has allowed the detection of cutaneous tumors, inflammatory processes, nail disorders and hair diseases. The skin weighs an average of , covers an area of , and is made of three distinct layers: the epidermis, dermis, and subcutaneous tissue. The two main types of human skin are glabrous skin, the nonhairy skin on the palms and soles (also referred to as the "palmoplantar" surfaces), and hair-bearing skin.

pos: Transdermal the need so arises. There are two important layers to the human skin: (1) the Epidermis and (2) the Dermis. For transdermal delivery, drugs must pass through the two sublayers of the epidermis to reach the microcirculation of the dermis. The Stratum corneum is the top layer of the skin and varies in thickness from approximately ten to several hundred micrometres, depending on the region of the body. It is composed of layers of dead, flattened keratinocytes surrounded by a lipid matrix, which together act as a brick-and-mortar system that is difficult to penetrate. The stratum corneum provides the most

pos: Absorption (skin) through the epidermis, glands, or hair follicles. Sweat glands and hair follicles make up about 0.1 to 1.0 percent of the total skin surface. Though small amounts of chemicals may enter the body rapidly through the glands or hair follicles, they are primarily absorbed through the epidermis. Chemicals must pass through the seven cell layers of epidermis before entering the dermis where they can enter the blood stream or lymph and circulate to other areas of the body. Toxins and toxicants can move through the layers by passive diffusion. The stratum corneum is the outermost layer of the epidermis and

pos: Human skin the epidermis, called the "papillary region", and a deep thicker area known as the "reticular region". The papillary region is composed of loose areolar connective tissue. It is named for its fingerlike projections called "papillae", that extend toward the epidermis. The papillae provide the dermis with a "bumpy" surface that interdigitates with the epidermis, strengthening the connection between the two layers of skin. In the palms, fingers, soles, and toes, the influence of the papillae projecting into the epidermis forms contours in the skin's surface. These epidermal ridges occur in patterns ("see:" fingerprint) that are genetically and epigenetically determined and

pos: Epidermis of the junctions, the actin immunofluorescence appears as a border between cells. The epidermis is composed of 4 or 5 layers, depending on the region of skin being considered. Those layers in descending order are: The Malpighian layer ("stratum malpighi") is both the stratum basale and stratum spinosum. The epidermis is separated from the dermis, its underlying tissue, by a basement membrane. As a stratified squamous epithelium, the epidermis is maintained by cell division within the stratum basale. Differentiating cell delaminate from the basement membrane and are displaced outwards through the epidermal layers, undergoing multiple stages of differentiation until, in

pos: Skin condition corneum. The dermis is the layer of skin between the epidermis and subcutaneous tissue, and comprises two sections, the papillary dermis and the reticular dermis. The superficial papillary dermis interdigitates with the overlying rete ridges of the epidermis, between which the two layers interact through the basement membrane zone. Structural components of the dermis are collagen, elastic fibers, and ground substance also called extra fibrillar matrix. Within these components are the pilosebaceous units, arrector pili muscles, and the eccrine and apocrine glands. The dermis contains two vascular networks that run parallel to the skin surface—one superficial and one deep plexus—which

pos: 7-Dehydrocholesterol the dermis, comprising largely connective tissue, and an outer, thinner epidermis. The thickness of the epidermis ranges from 0.08 mm to greater than 0.6 mm (from 0.003 to 0.024 inches). The epidermis comprises five "strata"; from outer to inner, they are the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. The highest concentrations of 7-dehydrocholesterol are found in the epidermal layer of skin—specifically in the stratum basale and stratum spinosum. The production of pre-vitamin D is, therefore, greatest in these two layers. Synthesis of pre-vitamin D in the skin involves UVB radiation, which effectively penetrates only the

pos: Integumentary system primarily made up of adipose tissue. Substantial collagen bundles anchor the dermis to the hypodermis in a way that permits most areas of the skin to move freely over the deeper tissue layers. The epidermis is the top layer of skin made up of epithelial cells. It does not contain blood vessels. Its main functions are protection, absorption of nutrients, and homeostasis. In structure, it consists of a keratinized stratified squamous epithelium ; four types of cells: keratinocytes, melanocytes, Merkel cells, and Langerhans cells. The major cell of the epidermis is the keratinocyte, which produces keratin. Keratin is a fibrous

pos: Integumentary system organ of the body. In humans, it accounts for about 12 to 15 percent of total body weight and covers 1.5-2m of surface area. The human skin (integument) is composed of at least two major layers of tissue: the epidermis and dermis. (The hypodermis or subcutaneous layer is not part of the skin.) The epidermis is the outermost layer, providing the initial barrier to the external environment. Beneath this, the dermis comprises two sections, the papillary and reticular layers, and contains connective tissues, vessels, glands, follicles, hair roots, sensory nerve endings, and muscular tissue. The deepest layer, the hypodermis, is

pos: Skin stages of cell differentiation to eventually become anucleated. During that process, keratinocytes will become highly organized, forming cellular junctions (desmosomes) between each other and secreting keratin proteins and lipids which contribute to the formation of an extracellular matrix and provide mechanical strength to the skin. Keratinocytes from the stratum corneum are eventually shed from the surface (desquamation). The epidermis contains no blood vessels, and cells in the deepest layers are nourished by diffusion from blood capillaries extending to the upper layers of the dermis. The epidermis and dermis are separated by a thin sheet of fibers called the basement membrane,

pos: Skin through a basement membrane and is structurally divided into two areas: a superficial area adjacent to the epidermis, called the "papillary region", and a deep thicker area known as the "reticular region". The papillary region is composed of loose areolar connective tissue.This is named for its fingerlike projections called "papillae" that extend toward the epidermis. The papillae provide the dermis with a "bumpy" surface that interdigitates with the epidermis, strengthening the connection between the two layers of skin. The reticular region lies deep in the papillary region and is usually much thicker. It is composed of dense irregular connective tissue,

pos: Skin condition Within the latter type, hairs in structures called pilosebaceous units have a hair follicle, sebaceous gland, and associated arrector pili muscle. In the embryo, the epidermis, hair, and glands are from the ectoderm, which is chemically influenced by the underlying mesoderm that forms the dermis and subcutaneous tissues. The epidermis is the most superficial layer of skin, a squamous epithelium with several strata: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Nourishment is provided to these layers via diffusion from the dermis, since the epidermis is without direct blood supply. The epidermis contains four cell types:

pos: Human skin 20 blood vessels, 60,000 melanocytes, and more than 1,000 nerve endings. The average human skin cell is about 30 micrometers in diameter, but there are variants. A skin cell usually ranges from 25-40 micrometers (squared), depending on a variety of factors. Skin is composed of three primary layers: the epidermis, the dermis and the hypodermis. Epidermis, "epi" coming from the Greek meaning "over" or "upon", is the outermost layer of the skin. It forms the waterproof, protective wrap over the body's surface which also serves as a barrier to infection and is made up of stratified squamous epithelium with an

pos: Dermis Dermis The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided into two layers, the superficial area adjacent to the epidermis called the papillary region and a deep thicker area known as the reticular dermis. The dermis is tightly connected to the epidermis through a basement membrane. Structural components of the dermis are collagen, elastic fibers, and extrafibrillar matrix. It also contains mechanoreceptors that provide the sense of touch

pos: Dermis membranes, the equivalent structures to dermal papillae are generally termed "connective tissue papillae", which interdigitate with the rete pegs of the superficial epithelium. Dermis The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided into two layers, the superficial area adjacent to the epidermis called the papillary region and a deep thicker area known as the reticular dermis. The dermis is tightly connected to the epidermis through a basement

pos: Skin grafting skin graft. Two layers of skin created from animal sources has been found to be useful in venous leg ulcers. Skin grafts can be: A split-thickness skin graft (STSG) is a skin graft including the epidermis and part of the dermis. Its thickness depends on the donor site and the needs of the person receiving the graft. It can be processed through a skin mesher which makes apertures onto the graft, allowing it to expand up to nine times its size. Split-thickness grafts are frequently used as they can cover large areas and the rate of autorejection is low. The

pos: Vitamin D SPF 15 decreases it by 98%. The skin consists of two primary layers: the inner layer called the dermis, composed largely of connective tissue, and the outer, thinner epidermis. Thick epidermis in the soles and palms consists of five strata; from outer to inner, they are: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Vitamin D is produced in the keratinocytes of two innermost strata, the stratum basale and stratum spinosum. Vitamin D can be synthesized only by a photochemical process. Phytoplankton in the ocean (such as coccolithophore and "Emiliania huxleyi") have been photosynthesizing vitamin D

pos: Artificial skin skin-like tissue grown in a laboratory, although this technology is still quite a way away from being viable for use in the medical field. 'Artificial skin' can also refer to flexible semiconductor materials that can sense touch for those with prosthetic limbs, (also experimental). The skin is the largest organ in the human body. Skin is made up of three layers, the epidermis, dermis and the fat layer, also called the hypodermis. The epidermis is the outer layer of skin that keeps vital fluids in and harmful bacteria out of the body. The dermis is the inner layer of skin

pos: Dermal fibroblast Dermal fibroblast 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. Using organelles (particularly the rough endoplasmic reticulum), dermal fibroblasts generate and maintain the connective tissue which unites separate cell layers. Furthermore, these dermal fibroblasts produce the protein molecules including laminin and fibronectin which comprise the extracellular matrix. By creating the extracellular matrix between the dermis and epidermis, fibroblasts allow the epithelial cells of the epidermis to affix the matrix, thereby allowing the epidermal cells to effectively join together to form the top layer

pos: Acne acne-associated postinflammatory hyperpigmentation. By interfering with new production of melanin in the epidermis, hydroquinone leads to less hyperpigmentation as darkened skin cells are naturally shed over time. Improvement in skin hyperpigmentation is typically seen within six months when used twice daily. Hydroquinone is ineffective for hyperpigmentation affecting deeper layers of skin such as the dermis. The use of a sunscreen with SPF 15 or higher in the morning with reapplication every two hours is recommended when using hydroquinone. Its application only to affected areas lowers the risk of lightening the color of normal skin but can lead to a temporary

pos: Annelid of segments, while others add segments throughout their lives. The phylum's name is derived from the Latin word "annelus", meaning "little ring". Annelids' cuticles are made of collagen fibers, usually in layers that spiral in alternating directions so that the fibers cross each other. These are secreted by the one-cell deep epidermis (outermost skin layer). A few marine annelids that live in tubes lack cuticles, but their tubes have a similar structure, and mucus-secreting glands in the epidermis protect their skins. Under the epidermis is the dermis, which is made of connective tissue, in other words a combination of cells

pos: Lutzner cells immune cells like B cells and T cells for example. Lutzner cells are involved with non-Hodgkin’s lymphoma. It is the most common type and diverse range of lymphoma. Normally, it occurs with a B cell becoming abnormal, but also occurs when a T cell becomes abnormal. The mutated cell then divides to create multiple cells. Lymphoma cells can be distributed all over the body and into various tissues. Lutzner cells are found in skin tissue, more specifically, the epidermis and dermis layers. An accumulation of Lutzner cells in the layers of the skin can cause cutaneous T-cell lymphoma. Cutaneous cell

pos: Paraneoplastic pemphigus and Helm revised the original criteria from Anhalt et al. into major and minor signs indicating PNP: Major: Minor: Microscopy of the skin sample obtained from the biopsy is used to detect the presence of cleavage within the dermis, epidermal acantholysis (breaking apart of the skin), dyskeratotic keratinocytes and vacuolar changes in the layers of the skin, interfacial dermatitis, and epidermal exocytosis. Presentation of these characteristics suggests PNP. The presence of Immunoglobulin G, A, or M in the epidermis is normal. Detection in other locations such as intercellular and areas below the epidermis (subepidermal), as well as along the dermoepidermal

pos: Blister skin due to leprosy. In dermatology today, the words "vesicle" and "bulla" refer to blisters of smaller or greater size, respectively. To heal properly, a blister should not be popped unless medically necessary. If popped, the excess skin should not be removed because the skin underneath needs that top layer to heal properly. A blister may form when the skin has been damaged by friction or rubbing, heat, cold or chemical exposure. Fluid collects between the upper layers of Skin (the epidermis) and the layers below (the dermis). This fluid cushions the tissue underneath, protecting it from further damage and

pos: Role of skin in locomotion and accessory areas for the patagia of a Ptychozoon kuhli, flying gecko, exhibiting the passive gliding mechanism consists of five layers; a layer of adipose tissue is surrounded by a layer of dermis on each side (ventral and dorsal) and a layer of epidermis is external to the two dermal layers. The distribution of the adipose tissue IS thickest close to the body wall. This thick layer of adipose tissue at close to the body wall is believed to provide a "safety factor" for the structural elements of the skin ( i.e. collagen fibers) near the body wall. The thick

pos: Diabetic foot ulcer bacteria and infection. Extra cellular matrix (or "ECM") is the external structural framework that cells attach to in multicellular organisms. The dermis lies below the epidermis, and these two layers are collectively known as the skin. Dermal skin is primarily a combination of fibroblasts growing in this matrix. The specific species of ECM of connective tissues often differ chemically, but collagen generally forms the bulk of the structure. Through the interaction of cell with its extracellular matrix (transmitted through the anchoring molecules classed as integrins) there forms a continuous association between cell interior, cell membrane and extracellular matrix components that

pos: Hand is tightly bound to the underlying tissue and bones. Compared to the rest of the body's skin, the hands' palms (as well as the soles of the feet) are usually lighter — and even much lighter in dark-skinned individuals, compared to the other side of the hand. Indeed, genes specifically expressed in the dermis of palmoplantar skin inhibit melanin production and thus the ability to tan, and promote the thickening of the stratum lucidum and stratum corneum layers of the epidermis. All parts of the skin involved in grasping are covered by papillary ridges (fingerprints) acting as friction pads. In

pos: Dermabrasion medical assistants, and most recently untrained individuals in their homes. Dermabrasion procedures are surgical, invasive procedures that typically require a local anaesthetic. Often they are performed in surgical suites or in professional medical centers. Since the procedure can typically remove the top to deeper layers of the epidermis, and extend into the reticular dermis, there is always minor skin bleeding. The procedure carries risks of scarring, skin discoloration, infections, and facial herpes virus (cold sore) reactivation. In aggressive dermabrasion cases, there is often tremendous skin bleeding and spray during the procedure that has to be controlled with pressure. Afterward, the

pos: Head and neck anatomy the atlas near the foramen magnum, a large hole () at the base of the skull. The atlas joins with the occipital condyle above and the axis below. The spinal cord passes through the foramen magnum. The head and neck is covered in skin and its appendages, termed the integumentary system. These include hair, sweat glands, sebaceous glands, and sensory nerves. The skin is made up of three microscopic layers: epidermis, dermis, and hypodermis. The epidermis is composed of stratified squamous epithelium and is divided into the following five sublayers or strata, listed in order from outer to inner: The

pos: Bullous pemphigoid Bullous pemphigoid Bullous pemphigoid is an autoimmune pruritic skin disease preferentially in elderly people, that may involve the formation of blisters (bullae) at the space between the epidermis and dermis skin layers. It is classified as a type II hypersensitivity reaction, with the formation of anti-hemidesmosome antibodies. Clinically, the earliest lesions may appear urticarial (like hives), but could also appear dermatitic, targetoid, lichenoid, nodular, or even without visible rash (essential pruritus). Tense bullae eventually erupt, most commonly at the inner thighs and upper arms, but the trunk and extremities are frequently both involved. Any part of the skin surface can

pos: Dermis uppermost layer of the dermis, the papillary dermis, and the ridges they form greatly increase the surface area between the dermis and epidermis. Because the main function of the dermis is to support the epidermis, this greatly increases the exchange of oxygen, nutrients, and waste products between these two layers. Additionally, the increase in surface area prevents the dermal and epidermal layers from separating from each other by strengthening the junction between them. With age, the papillae tend to flatten and sometimes increase in number. Dermal papillae also play a pivotal role in hair formation, growth and cycling. In mucous

pos: Hemidesmosome separate. EBS is caused by mutations coding for keratin, plectin and BPAG1e. With junctional epidermolysis bullosa, layers of the lamina lucida (part of the basal lamina) separate. This is caused by mutations in integrin α6β4, laminin 322 and BPAG2. In dystrophic epidermolysis bullosa, the layers of the papillary dermis separate from the anchoring fibrils. This is caused by mutations in the collagen 7 gene. Hemidesmosome Hemidesmosomes (HD) are very small stud-like structures found in keratinocytes of the epidermis of skin that attach to the extracellular matrix (ECM). They are similar in form to desmosomes when visualized by electron microscopy, however,

pos: Duchsustus Duchsustus is the animal's dermis, klaf is the epidermis, and gevil is both layers tanned unseparated. Duchsustus Duchsustus (, from Greek "dyschistos") is the name of a type of parchment used for religious writings in Judaism. It is originally a Greek word and one of three Talmudic names for animal skin. The other two are kelaf and gevil. The meanings of these terms, however, are the subject of controversy in Jewish law. According to the Talmud, a sefer Torah should, ideally, be written on gevil, but may also be on klaf, Tefillin must be written on Klaf, and Mezuzah should

pos: Langerhans cell Langerhans cell Langerhans cells are dendritic cells (antigen-presenting immune cells) of the skin, and contain organelles called Birbeck granules. They are present in all layers of the epidermis and are most prominent in the stratum spinosum. They also occur in the papillary dermis, particularly around blood vessels, as well as in the mucosa of the mouth, foreskin, and vaginal epithelium. They can be found in other tissues, such as lymph nodes, particularly in association with the condition Langerhans cell histiocytosis (LCH). In skin infections, the local Langerhans cells take up and process microbial antigens to become fully functional antigen-presenting cells.

pos: Bullous pemphigoid world each year. Animal models of bullous pemphigoid have been developed using transgenic techniques to produce mice lacking the genes for the two known autoantigens, dystonin and collagen XVII. Bullous pemphigoid Bullous pemphigoid is an autoimmune pruritic skin disease preferentially in elderly people, that may involve the formation of blisters (bullae) at the space between the epidermis and dermis skin layers. It is classified as a type II hypersensitivity reaction, with the formation of anti-hemidesmosome antibodies. Clinically, the earliest lesions may appear urticarial (like hives), but could also appear dermatitic, targetoid, lichenoid, nodular, or even without visible rash (essential pruritus).

pos: Lutzner cells in bone marrow then travel to the thymus via the secretion of the hormone thymosin. The secretion allows them to differentiate and mature. Once the mutated cell is developed, it patiently waits in the thymus until an antigen presents itself. When a cutaneous lymphocyte antigen is expressed in the skin, the CD4+ Lutzner cell travels to the epidermis and dermis layers of the skin in order to bind to the antigen. Mature lymphocytes are part of the specific immune system because they recognize previous invaders and assist the body in attacking these invaders. These cells have antibodies present on the

pos: Aerosol burn deodorants can be a convenient, easily available means to satisfy the compulsions. Depending on the duration of exposure aerosol-induced frostbite can vary in depth. Most injuries of this type only affect the epidermis, the outermost layer of skin. However, if contact with the aerosol is prolonged the skin will freeze further and deeper layers of tissue will be affected, causing a more serious burn that reaches the dermis, destroys nerves, and increases the risk of infection and scarring . When the skin thaws, pain and severe discomfort can occur in the affected area. There may be a smell of aerosol

pos: Skin and proteoglycans. Skin proteoglycans are varied and have very specific locations. For example, hyaluronan, versican and decorin are present throughout the dermis and epidermis extracellular matrix, whereas biglycan and perlecan are only found in the epidermis. It harbors many mechanoreceptors (nerve endings) that provide the sense of touch and heat through nociceptors and thermoreceptors. It also contains the hair follicles, sweat glands, sebaceous glands, apocrine glands, lymphatic vessels and blood vessels. The blood vessels in the dermis provide nourishment and waste removal from its own cells as well as for the epidermis. The dermis is tightly connected to the epidermis

neg: Human skin the epidermis are keratinocytes, melanocytes, Langerhans cells and Merkel cells. The epidermis helps the skin to regulate body temperature. Epidermis is divided into several layers where cells are formed through mitosis at the innermost layers. They move up the strata changing shape and composition as they differentiate and become filled with keratin. They eventually reach the top layer called "stratum corneum" and are sloughed off, or desquamated. This process is called "keratinization" and takes place within weeks. The outermost layer of the epidermis consists of 25 to 30 layers of dead cells. Epidermis is divided into the following 5 sublayers

neg: Itch show that itch receptors are found only on the top two skin layers, the epidermis and the epidermal/dermal transition layers. Shelley and Arthur had verified the depth by injecting individual itch powder spicules (Mucuna pruriens), and found that maximal sensitivity was found at the basal cell layer or the innermost layer of the epidermis. Surgical removal of those skin layers removed the ability for a patient to perceive itch. Itch is never felt in muscle or joints, which strongly suggests that deep tissue probably does not contain itch signaling apparatuses. Sensitivity to pruritic stimuli is evenly distributed across the skin,

neg: Epidermis body regions, their numbers remain the same in individual body regions in all human beings. In white and Asian skin the melanosomes are packed in "aggregates", but in black skin they are larger and distributed more evenly. The number of melanosomes in the keratinocytes increases with UV radiation exposure, while their distribution remain largely unaffected. Laboratory culture of keratinocytes to form a 3D structure (artificial skin) recapitulating most of the properties of the epidermis is routinely used as a tool for drug development and testing. Epidermis The epidermis is the outermost of the three layers that make up the skin,

neg: Laminar organization its laminar organization, due to the arrangement of cortical neurons into six distinct layers. The eye in mammals has an extensive laminar organization. There are three main layers – the outer fibrous tunic, the middle uvea, and the inner retina. These layers have sublayers with the retina having ten ranging from the outer choroid to the inner vitreous humor and including the retinal nerve fiber layer. The human skin has a dense laminar organization. The outer epidermis has four or five layers. Laminar organization A laminar organization describes the way certain tissues, such as bone membrane, skin, or brain tissues,

neg: Italian crested newt the layers of the epidermis. Keratinocytes are especially important to the newt’s physiological well-being because they are responsible for the absorption of sodium ions. When it comes time to shed the skin, these cells will thicken and flatten out and eventually become the skin the newt sheds. Since highly permeable skin is a favourable adaption this is the main source of osmoregulation in crested newts. Physically, skin also helps to limit water loss by the mucus and the intercellular spaces in the stratum corneum. The permeability of the skin varies depending on what part of the body the skin is

neg: Skin layers of the skin. It forms a protective barrier over the body's surface, responsible for keeping water in the body and preventing pathogens from entering, and is a stratified squamous epithelium, composed of proliferating basal and differentiated suprabasal keratinocytes. Keratinocytes are the major cells, constituting 95% of the epidermis, while Merkel cells, melanocytes and Langerhans cells are also present. The epidermis can be further subdivided into the following "strata" or layers (beginning with the outermost layer): Keratinocytes in the stratum basale proliferate through mitosis and the daughter cells move up the strata changing shape and composition as they undergo multiple

neg: Vertical mattress stitch sites of greater skin laxity such as closure of lax skin after removing a dermoid cyst. It is useful for deep lacerations, where it can replace two layers of deep and superficial sutures. It can help bring the deep layers together alone, allowing several simple interrupted or running stitches to close the remaining superficial skin. Vertical mattress sutures are not recommended for sites such as the palm of the hand, where important structures lie fairly superficial to the epidermis. The vertical mattress stitch is placed in a "far-far-near-near" order of bites. The "far-far" loop enters and exits the skin surface

neg: Abrasion (medical) Abrasion (medical) An abrasion is a wound caused by superficial damage to the skin, no deeper than the epidermis. It is less severe than a laceration, and bleeding, if present, is minimal. Mild abrasions, also known as "grazes" or "scrapes", do not scar or bleed, but deep abrasions may lead to the formation of scar tissue. A more traumatic abrasion that removes all layers of skin is called an avulsion. Abrasion injuries most commonly occur when exposed skin comes into moving contact with a rough surface, causing a grinding or rubbing away of the upper layers of the epidermis. The

neg: Stratum basale hyper-proliferative epidermis (from a skin disease). The "stratum basale" is primarily made up of basal keratinocyte stem cells, which can be considered the stem cells of the epidermis. They divide to form the keratinocytes of the stratum spinosum, which migrate superficially. Other types of cells found within the "stratum basale" are melanocytes (pigment-producing cells), Langerhans cells (immune cells), and Merkel cells (touch receptors). Stratum basale The stratum basale (basal layer, sometimes referred to as stratum germinativum) is the deepest layer of the five layers of the epidermis, the outer covering of skin in mammals. The "stratum basale" is a single

neg: Peloid and ailments. Peloids are widely used in cosmetology in the form of facial masks. Peloid mask applications result in mild exfoliation, short term hydration and changes in the oil content of the most superficial layer of the skin, the epidermis which consists of dead sloughed poorly compacted cells. However, there is no scientific evidence of any effect on the underlying deeper skin layers below the epidermis or on longer term skin health, such as wrinkle formation, dyspigmentation and loss of elasticity. Peloid Peloid is mud, or clay used therapeutically, as part of balneotherapy, or therapeutic bathing. Peloids consist of humus

neg: Neural plate create the neural tube. The figure demonstrates the development of the neural plate into the neural tube, which is where the neural crest cells are derived from as well. In primary neurulation, the layer of ectoderm divides into three sets of cells: the neural tube (future brain and spinal cord), epidermis (skin), and neural crest cells (connects epidermis and neural tube and will migrate to make neurons, glia, and skin cell pigmentation). During the stage of neural plate formation the embryo consists of three cell layers: the ectoderm that eventually forms the skin and neural tissues, the mesoderm that forms

neg: Hemidesmosome that cause disruption of hemidesmosome components can lead to skin blistering disorders between different layers of the skin. These are collectively coined epidermolysis bullosa, or EB. Typical symptoms include fragile skin, blister development, and erosion from minor physical stress. However, the disease also can manifest as erosions on the cornea, trachea, gastrointestinal tract, espophagus, muscular dystrophy and muscular deformity. Mutations in 12 different genes that code for parts of the hemidesmosome have led to epidermolysis bullosa. There are three types of EB: EB simplex (EBS), dystrophic EB (DEB) and junctional EB (JEB). In epidermolysis bullosa simplex, layers of the epidermis

neg: Desmoglein-1 Desmoglein-1 Desmoglein-1 is a protein that in humans is encoded by the "DSG1" gene. Desmoglein-1 is expressed everywhere in the skin epidermis, but mainly it is expressed in the superficial upper layers of the skin epidermis. Desmosomes are cell-cell junctions between epithelial, myocardial and certain other cell types. Desmoglein-1 is a calcium-binding transmembrane glycoprotein component of desmosomes in vertebrate epithelial cells. Currently, four desmoglein subfamily members have been identified and all are members of the cadherin cell adhesion molecule superfamily. These desmoglein gene family members are located in a cluster on chromosome 18. The protein encoded by this gene has

neg: Skin flora that is not found in gut studies. Both gut and skin flora however lack the diversity found in soil flora. Skin flora The term skin flora (also commonly referred to as skin microbiota) refers to the microorganisms which reside on the skin, typically human skin. Many of them are bacteria of which there are around 1000 species upon human skin from nineteen phyla. Most are found in the superficial layers of the epidermis and the upper parts of hair follicles. Skin flora is usually non-pathogenic, and either commensal (are not harmful to their host) or mutualistic (offer a benefit). The

neg: Skin flora Skin flora The term skin flora (also commonly referred to as skin microbiota) refers to the microorganisms which reside on the skin, typically human skin. Many of them are bacteria of which there are around 1000 species upon human skin from nineteen phyla. Most are found in the superficial layers of the epidermis and the upper parts of hair follicles. Skin flora is usually non-pathogenic, and either commensal (are not harmful to their host) or mutualistic (offer a benefit). The benefits bacteria can offer include preventing transient pathogenic organisms from colonizing the skin surface, either by competing for nutrients, secreting

neg: Epidermis This inner layer is a germinal epithelium that gives rise to all epidermal cells. It divides to form the outer spinous layer ("stratum spinosum"). The cells of these two layers, together called the Malpighian layer(s) after Marcello Malpighi, divide to form the superficial granular layer ("Stratum granulosum") of the epidermis. The cells in the stratum granulosum do not divide, but instead form skin cells called keratinocytes from the granules of keratin. These skin cells finally become the cornified layer ("stratum corneum"), the outermost epidermal layer, where the cells become flattened sacks with their nuclei located at one end of the

neg: Desmoglein-1 as SAM syndrome - severe dermatitis, multiple allergies, and metabolic wasting. Desmoglein-1 has been shown to interact with PKP3, PKP2, and PTPRT(PTPrho) Desmoglein-1 Desmoglein-1 is a protein that in humans is encoded by the "DSG1" gene. Desmoglein-1 is expressed everywhere in the skin epidermis, but mainly it is expressed in the superficial upper layers of the skin epidermis. Desmosomes are cell-cell junctions between epithelial, myocardial and certain other cell types. Desmoglein-1 is a calcium-binding transmembrane glycoprotein component of desmosomes in vertebrate epithelial cells. Currently, four desmoglein subfamily members have been identified and all are members of the cadherin cell adhesion

neg: Mites of livestock Laminosioptidae). Psoroptic mites feed superficially at the stratum corneum; the photograph of a histological section of skin infested with "Psoroptes ovis", and the photograph of the surface of a host's skin infested with "P. ovis" looking like white dots, show this type of feeding. Sarcoptic mites feed by burrowing within the living layers of the epidermis, mainly stratum spinosum. Demodectic mites feed in a position technically external to the skin, between the epidermis and the hair shaft in hair follicles. Dermanyssid and trombiculid mites feed whilst external to the skin by piercing the skin with, respectively, their chelicerae or a

neg: Keratinocyte Keratinocyte A keratinocyte is the predominant cell type in the epidermis, the outermost layer of the skin, constituting 90% of the cells found there. Those keratinocytes found in the basal layer ("stratum basale") of the skin are sometimes referred to as "basal cells" or "basal keratinocytes". The primary function of keratinocytes is the formation of a barrier against environmental damage by pathogenic bacteria, fungi, parasites, viruses, heat, UV radiation and water loss. Once pathogens start to invade the upper layers of the epidermis, keratinocytes can react by producing proinflammatory mediators, particularly chemokines such as CXCL10 and CCL2 which attract leukocytes

neg: Stratum basale Stratum basale The stratum basale (basal layer, sometimes referred to as stratum germinativum) is the deepest layer of the five layers of the epidermis, the outer covering of skin in mammals. The "stratum basale" is a single layer of columnar or cuboidal cells. The cells are attached to each other and to the overlying stratum spinosum cells by desmosomes and hemidesmosomes. The nucleus is large, ovoid and occupies most of the cell. Some basal cells can act like stem cells with ability to divide and produced new cells , whereas others serve to anchor the epidermis glabrous skin (hairless), and

neg: Skin intricate fibers which pass over the gland's muscle and epithelial layers. The epidermis of birds and reptiles is closer to that of mammals, with a layer of dead keratin-filled cells at the surface, to help reduce water loss. A similar pattern is also seen in some of the more terrestrial amphibians such as toads. However, in all of these animals there is no clear differentiation of the epidermis into distinct layers, as occurs in humans, with the change in cell type being relatively gradual. The mammalian epidermis always possesses at least a stratum germinativum and stratum corneum, but the other

neg: Mammal atrium via one of the four [[pulmonary vein]]s. Blood flows nearly continuously back into the atrium, which acts as the receiving chamber, and from here through an opening into the left ventricle. Most blood flows passively into the heart while both the atria and ventricles are relaxed, but toward the end of the [[diastole|ventricular relaxation period]], the left atrium will contract, pumping blood into the ventricle. The heart also requires nutrients and oxygen found in blood like other muscles, and is supplied via [[coronary circulation|coronary arteries]]. The [[skin|integumentary system]] is made up of three layers: the outermost [[epidermis (skin)|epidermis]], the

neg: Stratum lucidum Stratum lucidum The stratum lucidum (Latin for "clear layer") is a thin, clear layer of dead skin cells in the epidermis named for its translucent appearance under a microscope. It is readily visible by light microscopy only in areas of thick skin, which are found on the palms of the hands and the soles of the feet. Located between the stratum granulosum and stratum corneum layers, it is composed of three to five layers of dead, flattened keratinocytes. The keratinocytes of the stratum lucidum do not feature distinct boundaries and are filled with eleidin, an intermediate form of keratin. They

neg: Skin fish have hard protective scales on their skin for protection, and birds have hard feathers, all made of tough β-keratins. Amphibian skin is not a strong barrier, especially regarding the passage of chemicals via skin and is often subject to osmosis and diffusive forces. For example, a frog sitting in an anesthetic solution would be sedated quickly, as the chemical diffuses through its skin. Amphibian skin plays key roles in everyday survival and their ability to exploit a wide range of habitats and ecological conditions. Mammalian skin is composed of two primary layers: The epidermis is composed of the outermost

neg: Ectoderm Ectoderm Ectoderm is one of the three primary germ layers in the very early embryo. The other two layers are the mesoderm (middle layer) and endoderm (most proximal layer), with the ectoderm as the most exterior (or distal) layer. It emerges and originates from the outer layer of germ cells. The word ectoderm comes from the Greek "ektos" meaning "outside", and "derma", meaning "skin." Generally speaking, the ectoderm differentiates to form the nervous system (spine, peripheral nerves and brain), tooth enamel and the epidermis (the outer part of integument). It also forms the lining of mouth, anus, nostrils, sweat glands,

neg: Spinous cell Spinous cell Spinous cells, or prickle cells, are keratin producing epidermal cells owing their prickly appearance to their numerous intracellular connections. They make up the stratum spinosum (prickly layer) of the epidermis and provide a continuous net-like layer of protection for underlying tissue. They are susceptible to mutations caused by sunlight and can become malignant. Spinous cells are found in the superficial layers of the skin. They are found in the stratum spinosum (prickly layer, spinosum layer), which lies above the stratum basale (basal layer) and below the stratum granulosum (granular layer) of the epidermis. The spinous cells are arranged

neg: Spinous cell two ways. First, they are keratinocytes (keratin cells) whose primary function is to produce keratin, a strong structural protein. The keratin accumulates within each spinous cell as it moves upward through the epidermis layers, until the cell is almost completely filled with hardening keratin (keratinisation). Second, the cells are bound together across their cytoplasm by keratin filaments that form cell-to-cell connections (desmosomes). Spinocellular carcinoma (prickle cell carcinoma) is relatively common in people over age 60, with fair skin, and a history of longer term sun exposure. It is not as commonly known as other skin cancers because it is less

neg: Corneocyte Corneocyte Corneocytes are terminally differentiated keratinocytes and compose most if not all of the stratum corneum, the outermost part of the epidermis. They are regularly replaced through desquamation and renewal from lower epidermal layers, making them an essential part of the skin barrier property. Corneocytes are keratinocytes without nuclei and cytoplasmic organelles. They contain a highly insoluble cornified envelope within the plasma membrane, and lipids (fatty acids, sterols and ceramides) released from lamellar bodies within the epidermis. The corneocytes are interlocked with each other and organized as vertical columns of 10–30 cells to form the stratum corneum. Corneocytes in the

neg: Pemphigus foliaceus like this: "Normally, our immune system produces antibodies that attack viruses and harmful bacteria to keep us healthy. In people with pemphigus, however, the immune system mistakenly attacks the cells in the epidermis, or top layer of the skin, and the mucous membranes. The immune system produces antibodies against proteins in the skin known as desmogleins. These proteins form the glue that keeps skin cells attached and the skin intact. When desmogleins are attacked, skin cells separate from each other and fluid can collect between the layers of skin, forming blisters that do not heal. In some cases, these blisters

neg: Toner (skin care) Toner (skin care) In cosmetics, skin toner or simply toner refers to a lotion or wash designed to cleanse the skin and shrink the appearance of pores, usually used on the face. Toners can be applied to the skin in different ways: Users often apply moisturiser after toner has dried. These are the mildest form of toners; they contain water and a humectant such as glycerine, and little if any alcohol (0–10%). Humectants help to keep the moisture in the upper layers of the epidermis by preventing it from evaporating. A popular example of this is rosewater. These toners are

neg: Pallesthesia known as "pallhypesthesia". To determine whether a patient has diminished or absent pallesthesia, testing can be conducted using a tuning fork at 128 Hz by placing it on the skin overlying a bone. This works because bones are good resonators of vibrations. Pacinian corpuscles, Merkel disk receptors, and tactile corpuscles are all encapsulated nerve endings involved in tactile stimulation. The Pacinian corpuscles are located within the deeper layer of the skin, under the skin in the subcutaneous tissues, within muscles, in the periosteum, and other deeper layers of the body. The Merkel disk receptors are located in the superficial epidermis

neg: Desmoglein-3 Desmoglein-3 Desmoglein-3 is a protein that in humans is encoded by the "DSG3" gene. In the skin epidermis Desmoglein-3 is expressed in the basal lower layers of the epidermis, and dominates in terms of expression on mucosal surfaces compared to Desmoglein-1. Desmosomes are cell-cell junctions between epithelial, myocardial, and certain other cell types. Desmoglein 3 is a calcium-binding transmembrane glycoprotein component of desmosomes in vertebrate epithelial cells. Currently, four desmoglein subfamily members have been identified and all are members of the cadherin cell adhesion molecule superfamily. These desmoglein gene family members are located in a cluster on chromosome 18. This

neg: Mites of livestock males on the surface of their host's skin, burrow into the living layers of the epidermis (mainly the stratum spinosum). They make tunnels horizontal to the surface of the skin. Here, eggs are laid and development of larvae and nymphs occurs. The mites have low mobility and transmission between hosts occurs only during close contact. The feeding of the mites and their excretory products irritates and inflames the skin, causing intense pruritus. Dermal hypersensitivity reactions develop in the host. Chronic infestations lead to thickening of the skin by overproduction of epidermal cells (acanthosis), resulting in a characteristic depilated and scaly

neg: Cutaneous larva migrans of 1–2 weeks into the infectious larval form (filariform larvae). The filariform larvae can burrow through intact skin that comes into contact with soil or sand that is contaminated with feces. Although they are able to infect the deeper tissues of animals (through to the lungs and then the intestinal tract), humans are incidental hosts and the larvae are only able to penetrate the epidermis of the skin and thus create the typical wormlike burrows visible underneath the skin. These parasites apparently lack the collagenase enzymes required to penetrate through the basement membrane deeper into the dermal layers of the

neg: Desmoglein-3 vulgaris. Desmoglein 3 has been shown to interact with PKP3. Desmoglein-3 Desmoglein-3 is a protein that in humans is encoded by the "DSG3" gene. In the skin epidermis Desmoglein-3 is expressed in the basal lower layers of the epidermis, and dominates in terms of expression on mucosal surfaces compared to Desmoglein-1. Desmosomes are cell-cell junctions between epithelial, myocardial, and certain other cell types. Desmoglein 3 is a calcium-binding transmembrane glycoprotein component of desmosomes in vertebrate epithelial cells. Currently, four desmoglein subfamily members have been identified and all are members of the cadherin cell adhesion molecule superfamily. These desmoglein gene family

neg: Ctenophora that act as teeth. Like those of cnidarians, (jellyfish, sea anemones, etc.), ctenophores' bodies consist of a relatively thick, jelly-like mesoglea sandwiched between two epithelia, layers of cells bound by inter-cell connections and by a fibrous basement membrane that they secrete. The epithelia of ctenophores have two layers of cells rather than one, and some of the cells in the upper layer have several cilia per cell. The outer layer of the epidermis (outer skin) consists of: sensory cells; cells that secrete mucus, which protects the body; and interstitial cells, which can transform into other types of cell. In specialized

neg: Mites of domestic animals for burrowing. The females, after mating with males on the surface of their host's skin, burrow into the living layers of the epidermis (mainly the stratum spinosum). They make long tunnels horizontal to the surface of the skin. Eggs are laid in the tunnels and development of larvae and nymphs occurs in such tunnels. The feeding of the mites and their excretory products irritates and inflames the skin, causing intense pruritus. Dermal hypersensitivity reactions will develop in the host. Chronic infestations lead to thickening of the skin by overproduction of epidermal cells (acanthosis), resulting in a characteristic depilated and scaly

neg: TGM5 This continuously shed outer layer of the epidermis performs the main barrier function of the skin. Recessive loss-of-function mutations in TGM1 have been shown to cause lamellar ichthyosis, a disease characterized by excessive scaling and shedding of the outer epidermis (Huber et al. 1995; Parmentier et al. 1995; Russell et al. 1995). TGM5 mutations can cause Acral Peeling Skin Syndrome, an autosomal recessive genodermatosis characterized by the shedding of the outer epidermis. In the acral form, the dorsa of the hands and feet are predominantly affected. Ultrastructural analysis has revealed tissue separation at the junction between the granular cells and

neg: Human skin validated comprehensive grading scale has categorized the clinical findings of skin aging as laxity (sagging), rhytids (wrinkles), and the various facets of photoaging, including erythema (redness), and telangiectasia, dyspigmentation (brown discoloration), solar elastosis (yellowing), keratoses (abnormal growths) and poor texture. Cortisol causes degradation of collagen, accelerating skin aging. Anti-aging supplements are used to treat skin aging. Photoaging has two main concerns: an increased risk for skin cancer and the appearance of damaged skin. In younger skin, sun damage will heal faster since the cells in the epidermis have a faster turnover rate, while in the older population the skin becomes

neg: Corneocyte average area of corneocytes at the surface of the skin reaches approximately 1000 µm, but may vary according to anatomical location, age and external environmental conditions such as ultraviolet (UV) irradiation. Major constituents of corneocytes are keratin intermediate filaments organized in parallel bundles to form a matrix to give rigidity to the overall structure of the skin. Layers of corneocytes produce high mechanical strength which allow epidermis of the skin to perform its function as a physical, chemical and immunological barrier. For example, corneocytes act as UV barrier by reflecting the scattered UV radiation, protecting cells inside the body from

neg: Microwave burn capacitive coupling. Damage to epidermis has low extent unless the epidermis is very moist. The characteristic depth for lower-frequency microwave injury is about 1 cm. The heating rate of adipose tissue is much slower than of muscle tissue. Frequencies in millimeter wave range are absorbed in the topmost layer of skin, rich in thermal sensors. At lower frequencies, between 1–10 GHz, most of the energy is however absorbed in deeper layers; the threshold for cellular injury there lies at 42 °C while the pain threshold is at 45 °C, so a subjective perception may not be a reliable indicator of

neg: Human skin mainly found in the stratum corneum and epidermal layers. Nanorods are used in experiments because of their unique fluorescent properties but have shown mediocre penetration. Nanoparticles of different materials have shown skin’s permeability limitations. In many experiments, gold nanoparticles 40 nm in diameter or smaller are used and have shown to penetrate to the epidermis. Titanium oxide (TiO2), zinc oxide (ZnO), and silver nanoparticles are ineffective in penetrating the skin past the stratum corneum. Cadmium selenide (CdSe) quantum dots have proven to penetrate very effectively when they have certain properties. Because CdSe is toxic to living organisms, the particle must

neg: MiR-203 that in mice, the expression of miR-203 is significantly upregulated between E13.5 and E15.5, suggesting that it may be absent from multipotent progenitors of single-layered epidermis, but is induced upon stratification and differentiation. It also was expressed at high levels in differentiating cells such as hair follicles, epidermis and sebaceous glands. Wei "et al". demonstrated that in humans, miR-203 expression is first detectable at 17 weeks gestation in the suprabasal layers of epidermis, and this localization was conserved in the adult skin. When miR-203 is expressed prematurely, basal cells diminish their proliferative potential; and when it is absent, proliferation is

neg: Cnidaria exoskeletons. A few polyps collect materials such as sand grains and shell fragments, which they attach to their outsides. Some colonial sea anemones stiffen the mesoglea with sediment particles. Cnidaria are diploblastic animals; in other words, they have two main cell layers, while more complex animals are triploblasts having three main layers. The two main cell layers of cnidarians form epithelia that are mostly one cell thick, and are attached to a fibrous basement membrane, which they secrete. They also secrete the jelly-like mesoglea that separates the layers. The layer that faces outwards, known as the ectoderm ("outside skin"), generally

neg: Epithelium form is epithelia. Epithelium Epithelium () is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the epidermis, the outermost layer of the skin. There are three principal shapes of epithelial cell: squamous, columnar, and cuboidal. These can be arranged in a single layer of cells as simple epithelium, either squamous, columnar, or cuboidal, or in layers of two or more cells

neg: Epithelium Epithelium Epithelium () is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the epidermis, the outermost layer of the skin. There are three principal shapes of epithelial cell: squamous, columnar, and cuboidal. These can be arranged in a single layer of cells as simple epithelium, either squamous, columnar, or cuboidal, or in layers of two or more cells deep as stratified

neg: Junctional epidermolysis bullosa (medicine) the new epidermis was attached. The graft had integrated into the lower layers of skin within a month, curing the boy. The introduction of genetic changes could increase the chances of skin cancer in other patients, but if the treatment is deemed safe in the long term, scientists believe the approach could be used to treat other skin disorders. Junctional epidermolysis bullosa (medicine) Junctional epidermolysis bullosa is a skin condition characterized by blister formation within the lamina lucida of the basement membrane zone. Sufferers experience very fragile skin, with blisters and skin erosion occurring in response to relatively benign trauma.

neg: Skin whitening receptors with BW-723C86 "inhibits" melanogenesis while activation of 5-HT receptors with the amphetamine structural analog DOI "promotes" melanogenesis. The serotonin reuptake inhibitor (SRI) 6-nitroquipazine inhibits melanogenesis in-vitro. Keratinocytes in the skin: Within the skin, melanocytes are present in the basal layer of the epidermis; from these melanocytes originate dendrites that reach keratinocytes. Keratinocytes are the most abundant cell type in the epidermis. In the skin, there are approximately 36 keratinocytes per melanocyte. Keratinocytes are continuously generated in the basal layer of the epidermis and displace older keratinocytes of the skin towards the surface. Melanosome transfer: Melanosomes along with the melanin

neg: Grey column information about non-painful touch and A delta fibers which are slower and thinner than the A beta fibers. The C fibers are not myelinated and therefore slower. C fibers that carry nociceptive signals can be divided into two types: fibers that contain neuropeptides, like substance P, and fibers that do not contain neuropeptides. The two types terminate in very different areas. Non-peptidergic C fibers are linked to the skin, where they innervate the epidermis while peptidergic C fibers innervate other tissues and deeper parts of the skin. There are two main types of nociceptive signals: sensory and affective. Sensory nociceptive

neg: Caucasian race skin than in other races. These traits cause problems in warm climates, but the nearly transparent skin allows more sunlight to reach the inner layers of the epidermis, thereby increasing Vitamin D production far above the level found in other racial groups. A study of skin cultured from the hip region of Europeans and Africans living in Nigeria showed that European skins allow penetration of between 3 and 4 times as much UV radiation incident upon the skin. Drawing from Petrus Camper's theory of facial angle, Blumenbach and Cuvier classified races, through their skull collections based on their cranial features

neg: CHUK after birth due to dehydration. Their epidermis retains a proliferative precursor cell population and lacks the outer two most differentiated cell layers. This function of IKK-α has been shown to be independent of the protein's kinase activity and of the NF-κB pathway. Instead it is thought that IKK-α regulates skin differentiation by acting as a cofactor in the TGF-β / Smad2/3 signaling pathway. The zebrafish homolog of IKK-α has also been shown to play a role in the differentiation of the embryonic epithelium. Zebrafish embryos born from mothers that are mutant in IKK-α do not produce a differentiated outer epithelial

neg: Hyaluronic acid scavenging function and its role in keratinocyte proliferation and migration. In normal skin, HA is found in relative high concentrations in the basal layer of the epidermis where proliferating keratinocytes are found. CD44 is collocated with HA in the basal layer of epidermis where additionally it has been shown to be preferentially expressed on plasma membrane facing the HA-rich matrix pouches. Maintaining the extracellular space and providing an open, as well as hydrated, structure for the passage of nutrients are the main functions of HA in epidermis. A report found HA content increases at the presence of retinoic acid (vitamin

neg: Seed generally between four and eight organised into three layers: (a) outer epidermis, (b) outer pigmented zone of two to five layers containing tannin and starch, and (c) inner epidermis. The endotegmen is derived from the inner epidermis of the inner integument, the exotegmen from the outer surface of the inner integument. The endotesta is derived from the inner epidermis of the outer integument, and the outer layer of the testa from the outer surface of the outer integument is referred to as the exotesta. If the exotesta is also the mechanical layer, this is called an exotestal seed, but if

neg: Epidermis due to the stratum corneum and is critical for maintaining healthy skin. Lipids arranged through a gradient and in an organized manner between the cells of the stratum corneum form a barrier to transepidermal water loss. The amount and distribution of melanin pigment in the epidermis is the main reason for variation in skin color in "Homo sapiens". Melanin is found in the small melanosomes, particles formed in melanocytes from where they are transferred to the surrounding keratinocytes. The size, number, and arrangement of the melanosomes vary between racial groups, but while the number of melanocytes can vary between different

neg: Monoi oil a skin-soothing agent. It is a naturally concentrated emollient which penetrates the skin, re-hydrates the layers of the epidermis and shields skin against external damages including sun and wind. Monoi oil is used: Monoi oil Monoï oil is an infused perfume-oil made from soaking the petals of Tahitian gardenias (best known as Tiaré flowers) in coconut oil. Monoï (pronounced Mah-noy) is a Tahitian word meaning "scented oil" in the Reo-Maohi language. Monoï is widely used among French Polynesians as a skin and hair softener. It is also popular in Europe and gaining recognition in the United States. Authentic Tahitian monoi

neg: Human skin of such particle transfer has prompted developments in nanomedicine and biology to increase skin permeability. One application of transcutaneous particle delivery could be to locate and treat cancer. Nanomedical researchers seek to target the epidermis and other layers of active cell division where nanoparticles can interact directly with cells that have lost their growth-control mechanisms (cancer cells). Such direct interaction could be used to more accurately diagnose properties of specific tumors or to treat them by delivering drugs with cellular specificity. Nanoparticles 40 nm in diameter and smaller have been successful in penetrating the skin. Research confirms that nanoparticles larger

neg: Abrasion (medical) caused by sliding on concrete. Abrasion (medical) An abrasion is a wound caused by superficial damage to the skin, no deeper than the epidermis. It is less severe than a laceration, and bleeding, if present, is minimal. Mild abrasions, also known as "grazes" or "scrapes", do not scar or bleed, but deep abrasions may lead to the formation of scar tissue. A more traumatic abrasion that removes all layers of skin is called an avulsion. Abrasion injuries most commonly occur when exposed skin comes into moving contact with a rough surface, causing a grinding or rubbing away of the upper