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Acid Mantle
The acid mantle is a very thin, delicate, slightly acidic film covering the entire surface of human skin, serving as a protective barrier against pathogens and reduces body odor. The acidic pH at the skin's surface mainly maintained by free amino acids and α-hydroxy acids (lactic acids) excreted from sweat; free fatty acids and amino acids from sebum; and urocanic acid and pyroglutamic acid. While the viable epidermis below the stratum corneum has a neutral pH of around 7.0, the surface pH of the skin's acid mantle typically ranges between 4.5 and 6.5, with an average assumption of 5.0 to 6.0. Formation and maintenance The acidic pH at the skin's surface is mainly maintained by free amino acids and α-hydroxy acids (lactic acids) excreted from sweat; free fatty acids and amino acids from sebum; and urocanic acid and pyroglutamic acid. Role The acid mantle, and its acidic pH, is important for the biological processes that are important for epidermal barrier function. Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acidic
An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen cation, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid. The first category of acids are the proton donors, or Brønsted–Lowry acids. In the special case of aqueous solutions, proton donors form the hydronium ion H3O+ and are known as Arrhenius acids. Brønsted and Lowry generalized the Arrhenius theory to include non-aqueous solvents. A Brønsted–Lowry or Arrhenius acid usually contains a hydrogen atom bonded to a chemical structure that is still energetically favorable after loss of H+. Aqueous Arrhenius acids have characteristic properties that provide a practical description of an acid. Acids form aqueous solutions with a sour taste, can turn blue litmus red, and react with bases and certain metals (like calcium) to form salts. The word ''acid'' is derived from the Latin , meaning 'sour'. An aqueous solution of an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroglutamic Acid
Pyroglutamic acid (also known as PCA, 5-oxoproline, pidolic acid) is a ubiquitous but understudied natural amino acid derivative in which the free amino group of glutamic acid or glutamine cyclizes to form a lactam. The names of pyroglutamic acid conjugate base, anion, salts, and esters are pyroglutamate, 5-oxoprolinate, or pidolate. It is a metabolite in the glutathione cycle that is converted to glutamate by 5-oxoprolinase. Pyroglutamate is found in many proteins including bacteriorhodopsin. ''N''-terminal glutamic acid and glutamine residues can spontaneously cyclize to become pyroglutamate, or enzymatically converted by glutaminyl cyclases. This is one of several forms of blocked ''N''-termini which present a problem for ''N''-terminal sequencing using Edman chemistry, which requires a free primary amino group not present in pyroglutamic acid. The enzyme pyroglutamate aminopeptidase can restore a free ''N''-terminus by cleaving off the pyroglutamate residue. Pyroglutami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skin Care
Skin care or skincare is the practice of maintaining and improving the health and appearance of the skin. It includes washing, moisturizing, protecting from the sun, and treating skin problems like acne and dryness. Skin care can help prevent infections and irritation and is an important part of daily hygiene. Skin care is at the interface of cosmetics and dermatology. Skin care differs from dermatology by its inclusion of non-physician professionals, such as estheticians and nursing staff. Skin care includes modifications of individual behavior and of environmental and working conditions. Skin care is an essential part of wound healing, radiation therapy, and the management of some medications. General care The skin is the largest organ in the human body. It protects against germs, dirt, and harmful substances. Simple habits like washing and applying lotion can make a big difference in skin health, but little is known scientifically about the benefits and clinical effica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skin Immunity
Skin immunity is a property of skin that allows it to resist infections from pathogens. In addition to providing a passive physical barrier against infection, the skin also contains elements of the innate and adaptive immune systems which allows it to actively fight infections. Hence the skin provides defense in depth against infection. 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. Shortly after infection, the immune adaptive response is induced by dendritic cells (Langerhans cells) present in the epidermis; they are responsible for the capture, processing, and presentation of antigens to T lymphocytes in local lymphoid organs. As a result, T lymphocytes express the cutaneous lymphocyte antigen (CLA) molecule, a modified form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symbiosis
Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biological interaction, between two organisms of different species. The two organisms, termed symbionts, can for example be in Mutualism (biology), mutualistic, commensalism, commensalistic, or parasitism, parasitic relationships. In 1879, Heinrich Anton de Bary defined symbiosis as "the living together of unlike organisms". The term is sometimes more exclusively used in a restricted, mutualistic sense, where both symbionts contribute to each other's subsistence. This means that they benefit each other in some way. Symbiosis can be ''obligate'' (or ''obligative''), which means that one, or both of the organisms depend on each other for survival, or ''facultative'' (optional), when they can also subsist independently. Symbiosis is also classified by physical attachment. Symbionts forming a single body live ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skin Flora
Skin flora, also called skin microbiota, refers to microbiota (community (ecology), communities of microorganisms) that reside on the skin, typically human skin. Many of them are bacterium, bacteria of which there are around 1,000 species upon human skin from nineteen Phylum, phyla. Most are found in the superficial layers of the Epidermis (skin), epidermis and the upper parts of hair follicles. Skin flora is usually non-pathogenic, and either commensalism, commensal (are not harmful to their host) or Mutualism (biology), mutualistic (offer a benefit). The benefits bacteria can offer include preventing transient pathogenic organisms from Infection#Colonization, colonizing the skin surface, either by competing for nutrients, secreting chemicals against them, or stimulating the skin's immune system. However, resident microbes can cause skin diseases and enter the blood system, creating life-threatening diseases, particularly in immunosuppressed people. A major non-human skin flora ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratum Corneum
The stratum corneum (Latin language, Latin for 'horny layer') is the outermost layer of the epidermis (skin), epidermis. Consisting of dead tissue, it protects underlying tissue from infection, dehydration, chemicals and mechanical stress. It is composed of 15–20 layers of flattened cells with no nuclei and cell organelles. Among its properties are mechanical shear, impact resistance, water flux and hydration regulation, microbial proliferation and invasion regulation, initiation of inflammation through cytokine activation and dendritic cell activity, and selective permeability to exclude toxins, irritants, and allergens. The cytoplasm of its cells shows filamentous keratin. These corneocytes are embedded in a lipid matrix composed of ceramides, cholesterol, and fatty acids. Desquamation is the process of cell shedding from the surface of the stratum corneum, balancing proliferating keratinocytes that form in the stratum basale. These cells migrate through the epidermis tow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidermis
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and Subcutaneous tissue, hypodermis. The epidermal 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 stratified squamous epithelium, multiple layers of flattened cells that overlie a base layer (stratum basale) composed of Epithelium#Cell types, columnar cells arranged perpendicularly. The layers of cells develop from stem cells in the basal layer. The thickness of the epidermis varies from 31.2μm for the penis to 596.6μm for the Sole (foot), sole of the foot with most being roughly 90μm. Thickness does not vary between the sexes but becomes thinner with age. The human epidermis is an example of epithelium, particularly a stratified squamous epithelium. The word epidermis is derived through Latin , itself and . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urocanic Acid
Urocanic acid (formally ''trans''-Urocanic acid) is an intermediate in the catabolism of L-histidine. The cis-urocanic acid, ''cis''-urocanic acid isomer is rare. Metabolism It is formed from L-histidine through the action of histidine ammonialyase (also known as histidase or histidinase) by elimination of ammonium. In the liver, urocanic acid is transformed by urocanate hydratase (or urocanase) to 4-imidazolone-5-propionic acid and subsequently to glutamic acid. Clinical significance Inherited deficiency of urocanase leads to elevated levels of urocanic acid in the urine, a condition known as urocanic aciduria. An important role for the onset of atopic dermatitis and asthma has been attributed to filaggrin, a skin precursor of urocanic acid. Urocanic acid is thought to be a significant attractant of the nematode parasite ''Strongyloides stercoralis'', in part because of relatively high levels in the plantar surfaces of the feet, the site through which this parasite often enters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Skin
The human skin is the outer covering of the body and is the largest organ of the integumentary system. The skin has up to seven layers of ectodermal tissue (biology), tissue guarding Skeletal muscle, muscles, bones, ligaments and organ (anatomy), internal organs. Human skin is similar to most of the other mammals' skin, and it is very similar to pig skin. Though nearly all human skin is covered with hair follicles, it can appear Nudity#Evolution of hairlessness, hairless. There are two general types of skin: hairy and glabrous skin (hairless). The adjective List of medical roots, suffixes and prefixes#C, ''cutaneous'' literally means "of the skin" (from Latin ''cutis'', skin). Skin plays an important immunity (medical), immunity role in protecting the body against pathogens and excessive transepidermal water loss, water loss. Its other functions are Thermal insulation, insulation, thermoregulation, temperature regulation, sensation, synthesis of vitamin D, and the protection ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sebum
A sebaceous gland or oil gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest number on the face and scalp, but also on all parts of the skin except the palms of the hands and soles of the feet. In the eyelids, meibomian glands, also called tarsal glands, are a type of sebaceous gland that secrete a special type of sebum into tears. Surrounding the female nipples, areolar glands are specialized sebaceous glands for lubricating the nipples. Fordyce spots are benign, visible, sebaceous glands found usually on the lips, gums and inner cheeks, and genitals. Structure Location In humans, sebaceous glands are found throughout all areas of the skin, except the palms of the hands and soles of the feet. There are two types of sebaceous glands: those connected to hair follicles and those that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sweat
Perspiration, also known as sweat, is the fluid secreted by sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and Apocrine sweat gland, apocrine glands. The eccrine sweat glands are distributed over much of the body and are responsible for secreting the watery, brackish sweat most often triggered by excessive body temperature. Apocrine sweat glands are restricted to the armpits and a few other areas of the body and produce an odorless, oily, opaque secretion which then gains its characteristic odor from bacterial decomposition. In humans, sweating is primarily a means of thermoregulation, which is achieved by the water-rich secretion of the eccrine glands. Maximum sweat rates of an adult can be up to per hour or per day, but is less in children prior to puberty. Evaporation of sweat from the skin surface has a cooling effect due to evaporative cooling. Hence, in Temperature, hot weather, or when the individual's muscles hea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
