Epidermis Health Dictionary

Epidermis: From 3 Different Sources


The thin outermost layer of the skin.
Health Source: BMA Medical Dictionary
Author: The British Medical Association
The outer layer of the SKIN, which forms the protective covering of the body.
Health Source: Medical Dictionary
Author: Health Dictionary
n. the outer layer of the *skin, which is divided into four layers (see illustration). The innermost Malpighian or germinative layer (stratum germinativum) consists of continuously dividing cells. The other three layers are continually renewed as cells from the germinative layer are gradually pushed outwards and become progressively impregnated with keratin (see keratinization). The outermost layer (stratum corneum) consists of dead cells whose cytoplasm has been entirely replaced by keratin. It is thickest on the soles of the feet and palms of the hands. —epidermal adj.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Desquamation

The scaling-o? of the super?cial layer of the epidermis (see SKIN).... desquamation

Melanin

Pigment which confers colour on the SKIN, hair and EYE. It is produced by cells called melanocytes interspersed along the basal layer of the EPIDERMIS. The maturation of the epidermis into stratum corneum cells packed with melanin granules confers an ultraviolet light barrier which protects the skin against the harmful effects resulting from continued solar exposure. The races do not di?er in the number of melanocytes in their skin, only in the rate and quantity of melanin production. Exposure to bright sunlight stimulates melanin production and distribution causing ‘suntan’. A hormone from the PITUITARY GLAND may stimulate melanin production on the face in pregnancy (see CHLOASMA).... melanin

Melanocyte

Clear branching cell in the epidermis of the SKIN that produces tyrosinase (an ENZYME) and MELANIN.... melanocyte

Skin

The membrane which envelops the outer surface of the body, meeting at the body’s various ori?ces, with the mucous membrane lining the internal cavities.

Structure

CORIUM The foundation layer. It overlies the subcutaneous fat and varies in thickness from 0·5–3.0 mm. Many nerves run through the corium: these have key roles in the sensations of touch, pain and temperature (see NEURON(E)). Blood vessels nourish the skin and are primarily responsible for regulating the body temperature. Hairs are bedded in the corium, piercing the epidermis (see below) to cover the skin in varying amounts in di?erent parts of the body. The sweat glands are also in the corium and their ducts lead to the surface. The ?brous tissue of the corium comprises interlocking white ?brous elastic bundles. The corium contains many folds, especially over joints and on the palms of hands and soles of feet with the epidermis following the contours. These are permanent throughout life and provide unique ?ngerprinting identi?cation. HAIR Each one has a root and shaft, and its varying tone originates from pigment scattered throughout it. Bundles of smooth muscle (arrectores pilorum) are attached to the root and on contraction cause the hair to stand vertical. GLANDS These occur in great numbers in the skin. SEBACEOUS GLANDS secrete a fatty substance and sweat glands a clear watery ?uid (see PERSPIRATION). The former are made up of a bunch of small sacs producing fatty material that reaches the surface via the hair follicle. Around three million sweat or sudoriparous glands occur all over the body surface; sited below the sebaceous glands they are unconnected to the hairs. EPIDERMIS This forms the outer layer of skin and is the cellular layer covering the body surface: it has no blood vessels and its thickness varies from 1 mm on the palms and soles to 0·1 mm on the face. Its outer, impervious, horny layer comprises several thicknesses of ?at cells (pierced only by hairs and sweat-gland openings) that are constantly rubbed o? as small white scales; they are replaced by growing cells from below. The next, clear layer forms a type of membrane below which the granular stratum cells are changing from their origins as keratinocytes in the germinative zone, where ?ne sensory nerves also terminate. The basal layer of the germinative zone contains melanocytes which produce the pigment MELANIN, the cause of skin tanning.

Nail A modi?cation of skin, being analagous to the horny layer, but its cells are harder and more adherent. Under the horny nail is the nail bed, comprising the well-vascularised corium (see above) and the germinative zone. Growth occurs at the nail root at a rate of around 0·5 mm a week – a rate that increases in later years of life.

Skin functions By its ability to control sweating and open or close dermal blood vessels, the skin plays a crucial role in maintaining a constant body temperature. Its toughness protects the body from mechanical injury. The epidermis is a two-way barrier: it prevents the entry of noxious chemicals and microbes, and prevents the loss of body contents, especially water, electrolytes and proteins. It restricts electrical conductivity and to a limited extent protects against ultraviolet radiation.

The Langerhans’ cells in the epidermis are the outposts of the immune system (see IMMUNITY), just as the sensory nerves in the skin are the outposts of the nervous system. Skin has a social function in its ability to signal emotions such as fear or anger. Lastly it has a role in the synthesis of vitamin D.... skin

Bayberry

Myrica cerifera. N.O. Myricaceae.

Synonym: Candleberry, Waxberry, Wax Myrtle.

Habitat: Near the sea in pastures and on stony soils.

Features ? The bark has a white, peeling epidermis covering a hard, reddish-brown layer beneath. It is slightly fibrous on the inner surface, and the fracture is granular. The taste is pungent, astringent and bitter, the odour faintly aromatic.

Part used ? The bark is the only part of the Bayberry shrub now used as a medicine.

Action: A powerful stimulant, astringent and tonic to the alimentary tract.

Bayberry bark is one of the most widely used agents in the herbal practice. It figures in many of the compound powders and is the base of the celebrated composition powder, a prescription of which will be found in the "Herbal Formulae" section of this volume. In cases of coldness of the extremities, chills and influenza, an infusion of 1 ounce of the powdered bark to 1 pint of water is taken warm. This assists circulation and promotes perspiration, especially when combined with Cayenne as in

the formula referred to above.

As an antiseptic the powder is added to poultices for application to ulcers, sores and wounds. It also makes an excellent snuff for nasal catarrh, and an ingredient in tooth powders, for which a prescription is given in the section previously mentioned.

The virtues of Bayberry bark were recognized and used beneficially by the herbalists of many generations ago. Indeed, their enthusiasm for this, as for certain other remedies also extremely efficacious within proper limits, led them to ascribe properties to the bark which it does not possess. Many affections of the uterine system, fistula, and even cancer were said to yield to its influence.

Even in these cases, however, Bayberry bark certainly did less harm than many of the methods employed by the more orthodox practitioners of that time !... bayberry

Bowen’s Disease

An uncommon chronic localised skin disease, presenting as a solitary chronic ?xed irregular plaque mimicking eczema or psoriasis. It is a fairly benign form of CARCINOMA in situ in the EPIDERMIS but can occasionally become invasive. It is curable by CRYOTHERAPY or surgical excision.... bowen’s disease

Callosities

Areas of gross thickening of the epidermis in response to trauma. They usually occur on a foot due to bony deformity or ill-?tting footwear. (See CORNS AND BUNIONS.)... callosities

Corns And Bunions

A corn is a localised thickening of the cuticle or epidermis (see SKIN) affecting the foot. The thickening is of a conical shape; the point of the cone is directed inwards and is known as the ‘eye’ of the corn. A general thickening over a wider area is called a callosity. Bunion is a condition found over the joint at the base of the big toe, in which not only is there thickening of the skin, but the head of the metatarsal bone also becomes prominent. Hammer-toe is a condition of the second toe, often caused by short boots, in which the toe becomes bent at its two joints in such a way as to resemble a hammer.

Corns and bunions are caused by badly ?tting shoes, hence the importance of children and adults wearing properly ?tted footwear. Corns can be pared after softening in warm water, or painted with salicylic acid collodion or other proprietary preparations. Bad corns may need treatment by a chiropodist (see CHIROPODY). Bunions may require surgical treatment. Regular foot care is important in patients with DIABETES MELLITUS.... corns and bunions

Epithelium

Epithelium is the cellular layer which forms the epidermis on the skin, covers the inner surface of the bowels, and forms the lining of ducts and hollow organs, like the bladder. It consists of one or more layers of cells which adhere to one another, and is one of the simplest tissues of the body. It is of several forms: for example, the epidermis is formed of scaly epithelium, the cells being in several layers and more or less ?attened. (See SKIN.) The bowels are lined by a single layer of columnar epithelium, the cells being long and narrow in shape. The air passages are lined by ciliated epithelium: that is to say, each cell is provided with ?agellae (lashes) which drive the ?uid upon the surface of the passages gradually upwards.... epithelium

Freckles

Also known as ephelides, these are small, brown, ?at spots on the skin. They occur mostly in blonde or red-haired subjects in exposed areas, and darken on exposure to the sun. Melanocytes (see MELANOCYTE) are not increased in the basal layer of the EPIDERMIS.... freckles

Mesogloea

The jelly part of a jellyfish - the thickened substance between the epidermis and gastrodermis that gives the jellyfish its shape.... mesogloea

Mucoepithelial

Tissues with mixed characteristics of both mucous membranes and epidermis, found around the entrances into the body.... mucoepithelial

Papilla

A small projection, such as those with which the corium of the skin is covered, and which project into the epidermis and make its union with the corium more intimate; or those covering the tongue and projecting from its surface.... papilla

Green Tea Or The Wonder Drug

Green tea is considered a “wonder drug” because of its healthy contribution in human diets. Its antioxidant properties fight successfully against cancer, but not only. Green tea description Green tea is made from Camellia sinensis, an Asian plant, originating from China, Japan and South Korea. Oolong tea and black tea are prepared from the same plant as the green tea. A special feature of this type of tea is the ability to block the natural process of fermentation: after being picked, its leaves are steamed, dried and then rolled, thus blocking fermentation. Due to its constituents, it acts as an antioxidant, diuretic, cerebral and fattening burning stimulator, and also as a cancer protector. Green tea has been the subject of many scientific and medical studies so as to determine its health benefits. It seems that regular green tea drinkers may have a lower risk of developing heart diseases and certain types of cancer. There are several types of green tea available on the market: Bancha Tea, Chun Hao Tea , Dao Ren Tea , Dragonwell Tea , Genmaicha Tea , Gunpowder , Gyokuro Tea , Hojicha Tea , Kai Hua Long Ding Tea, Kukicha Tea , Matcha Tea , Sencha Tea , White Monkey Tea. Green Tea brewing To prepare green tea, use: two grams of tea per 100ml of water, or one teaspoon of green tea per five ounce cup. Green tea steeping time varies from thirty seconds to two, three minutes. The temperature differs as well, from 140°F to 190°F. Consumers recommend that lower-quality green teas to be steeped hotter and longer and higher-quality teas to be steeped cooler and shorter. In case of steeping the green tea too hot or too long, the resulting beverage is bitter and astringent. Green Tea benefits Green Tea lowers the risk of cancer. Studies have shown the green tea’s contribution against tumors growth, due to its high content of antioxidants, able to fight free radicals which are responsible for cancer spreading. Green Tea lowers the risk of stroke and heart diseases. The formation of blood clots (or thrombosis) is the main cause of the heart attacks and strokes. Green Tea has been acknowledged to exhibit abnormal blood clot formation. Green Tea lowers blood pressure. Green Tea is proven to block the effects of an enzyme secreted by the kidneys, considered to be one of the main causes of hypertension. Green Tea prevents tooth decay. Dental plaque and bacterial colonies that occur on the tooth surfaces and cause tooth decay can be inhibited by one of the compounds of the green tea. Also, this beverage has been shown to be effective against fighting gum diseases. Green Tea inhibits viruses Studies revealed that green tea can kill certain bacteria and staphs. It blocks the development of several viruses such as viral hepatitis. Green tea has also been successful in:
  • Slowing early aging;
  • Diets;
  • The treatment of physical or intellectual fatigue;
  • Treating fast cold and flu recovery;
  • Preventing allergenic reactions;
  • Balancing body fluids;
  • Improving the immune function of the epidermis;
  • Preventing and mending arthritis;
  • Improving bone structure
Green Tea side effects Green tea is not recommended to patients suffering from high blood pressure, gastric acid secretion, gastritis and ulcer. Due to the amount of caffeine contained, scientists advise a reduced consumption of green tea for pregnant and nursing women. Also, this tea should not be drunk after 5 p.m., because the consumption may lead to insomnia, palpitations and agitation. Green tea is a well known beverage, especially due to its medicinal contribution to a large array of diseases such as arthritis, heart diseases and several types of cancer.... green tea or the wonder drug

Linum Usitatissimum

Linn.

Habitat: Cultivated mainly in Madhya Pradesh, Uttar Pradesh, Maharashtra, Bihar and Rajasthan.

English: Linseed, Flax.

Ayurvedic: Atasi, Umaa, Masrnaa, Nilapushpi, Kshumaa.

Unani: Kattan.

Siddha/Tamil: (Seed).

Action: Seed—demulcent, emollient, laxative, antilipidemic, antitussive, pectoral (used in bronchitis and cough). Flowers—used as nervine and cardiac tonic. Oil— used in burns, skin injuries and sores.

Key application: Internally, for chronic constipation, for colons damaged by abuse of laxatives, irritable bowel syndrome, diverticular disease, symptomatic short-term treatment of gastritis and enteritis. Externally, for painful skin inflammations. (German Commission E, ESCOP, The British Herbal Pharmacopoeia.)

The plant contains chlorogenic acid and its isomer. Also present are palmitic, stearic, oleic, linoleic acids, along with amino acids, and sugars. Linseed also contains mucilage (3-10%) in epidermis; fatty oil (30-40%); cyanogenic glycosides (0.05-00.1%) mainly linus- tatin, neolinustatin and linamarin; lig- nans; phenylpropane derivatives including linusitamarin. (Cyanogenic glycosides are not found toxic in therapeutic doses as these are broken down only to a limited extent in the body.)

The seeds are an excellent source of dietary alpha-linolenic acid for modifying plasma and tissue lipids. Flaxseed preparations reduced atherogenic risk in hyperlipemic patients. (Cited in Expanded Commission E Monographs.)

Human studies have indicated Flax- seed's use in atherosclerosis, hyperc- holesterolemia, lupus nephritis, chronic renal diseases and in cancer prevention (active principle: lignan precursor secoisolariciresinol diglycoside). (Sharon M. Herr. Also Am J Clin Nutr, 1999, 69, 395-402.)

The PP glucose response to a 50 g carbohydrate load given as Flaxseed bread was found to be 27% lower when compared with regular white bread.

Taking Flaxseed oil daily for 3 months did not improve symptoms of pain and stiffness in rheumatoid arthritis and no effect was observed on RA, such as C-reactive protein and ESR. (Natural Medicines Comprehensive Database, 2007.)

The water-binding capacity and rhe- ological properties of linseed mucilage resembled those of guar gum.

Dosage: Ripe seed—3-6 g powder. (API, Vol. I.) Flower-bud—3-6 g; oil—5-10 ml. (CCRAS.)... linum usitatissimum

Naevus

A congenitally determined tissue abnormality. In the SKIN, naevi of blood vessels are best known, but a MOLE is a MELANOCYTE naevus, and warty streaked and linear naevi of the epidermis occasionally occur. There are several patterns of vascular naevi:

Naevus simplex Also known as ‘salmon patch’. About one-third of white children are born with macular pink areas of ERYTHEMA on the nape, brow or eyelids which usually disappear after a few months, but patches on the nape may persist.

Naevus ?ammeus Also known as ‘portwine stain’ and present at birth. It is unilateral, usually on the face, and may be extensive. It tends to darken with age and is permanent. Laser treatment is e?ective.

Strawberry naevus (cavernous haemangioma) is usually not present at birth but appears within a few weeks and grows rapidly, reaching a peak in size after 6–12 months, when the lobulated red nodule may resemble a ripe strawberry. Untreated, the naevus disappears spontaneously over several years. It may occur anywhere and may be very troublesome when occurring around an eye or on the ‘nappy’ area. If possible it should be left alone, but where it is causing problems other than simply cosmetic ones it is best treated by an expert. This may involve medical treatment with steroids or interferon or laser therapy.

Spider naevus is due to a dilated ARTERIOLE causing a minute red papule in the skin, the small branching vessels resembling spider legs. A few spider naevi are common in young people, but multiple naevi are common in pregnancy and may also be a warning sign of chronic liver disease.... naevus

Papilloma

Proliferation of epidermis or epithelium (see SKIN) to form a tumour. Benign papillomas are common in the skin and are sometimes viral in origin. Papilloma of the urinary bladder may cause HAEMATURIA.... papilloma

Pemphigus

Autoimmune disease of the SKIN in which the cells of the epidermis lose their adhesion to each other, resulting in blister formation.

Pemphigus vulgaris is a serious form affecting skin and MUCOUS MEMBRANE. It affects young and middle-aged people with widespread blistering, erosion and crusting of the skin. Extensive involvement of the lips, mouth and throat interfere with nutrition. Untreated, it is eventually fatal, but the disease can now be controlled by large doses of oral CORTICOSTEROIDS and other immunosuppressive drugs. MORBIDITY from the adverse effects of steroids is a serious problem, but some patients are eventually cured.

Pemphigus foliaceus is seen in the elderly; the blistering is more super?cial in the epidermis. It may be very widespread, but is not life-threatening because mucous membranes are not affected. Topical corticosteroids will sometimes control the eruption, but in severe cases treatment is as for pemphigus vulgaris.

Pemphigoid is a variant where the blistering occurs because of separation of the epidermis and dermis. Mucosae are rarely affected and the disease affects mainly the arms and legs in the elderly. Treatment is as for pemphigus but smaller doses of corticosteroids usually su?ce.... pemphigus

Pyridoxine

Pyridoxine, or vitamin B, plays an important part in the metabolism of a number of AMINO ACIDS. De?ciency leads to ATROPHY of the EPIDERMIS, the hair follicles, and the SEBACEOUS glands, and peripheral NEURITIS may also occur. Young infants are more susceptible to pyridoxine de?ciency than adults: they begin to lose weight and develop a hypochromic ANAEMIA; irritability and CONVULSIONS may also occur. Liver, yeast and cereals are relatively rich sources of the vitamin; ?sh is a moderately rich source, but vegetables and milk contain little. The minimal daily requirement in the diet is probably about 2 mg. (See APPENDIX 5: VITAMINS.)... pyridoxine

Scabies

Sarcoptic infestation of the human skin particularly a contagious skin disease caused by invasion of the epidermis... scabies

Scalded-skin Syndrome

In infants, certain staphylococcal bacteria (see STAPHYLOCOCCUS) can cause an acute toxic illness in which the subject develops sheets of bright ERYTHEMA, accompanied by shedding of layers of outer epidermis. The result is similar to a hot-water scald. The condition responds promptly to appropriate antibiotic therapy. Drug reactions, especially from sulphonamides, may cause a similar syndrome in adults. In drug-induced forms, mucosae are also affected and the disease is often fatal.... scalded-skin syndrome

Scar

The name applied to a healed wound, ulcer or breach of tissue. A scar consists essentially of ?brous tissue, covered by an imperfect formation of epidermis in the case of scars on the surface of the skin. The ?brous tissue is produced by the connective tissue that migrates to the wound in the course of its repair (see WOUNDS). Gradually this ?brous tissue contracts, becomes more dense, and loses its blood vessels, leaving a hard white scar. (See also KELOID.)... scar

Suntan

Darkening of the skin after exposure to sunlight.

Specialized cells in the epidermis respond to ultraviolet light by producing the pigment melanin.

(See also sunlight, adverse effects of; sunburn.)... suntan

Acanthosis

n. an increase in the number of *prickle cells in the innermost layer of the epidermis, leading to thickening of the epidermis. Acanthosis nigricans is characterized by papillomatous growths, mainly in the armpits, neck, and groin, giving the skin a pigmented appearance and a velvety thickened texture. It may be associated with internal malignancy. Pseudoacanthosis nigricans is more common and is associated with obesity and *insulin resistance.... acanthosis

Benzoyl Peroxide

a preparation used in the treatment of acne. It acts by removing the surface layers of the epidermis and unblocking skin pores and has an antiseptic effect on skin bacteria. Side-effects may include skin irritation.... benzoyl peroxide

Clark’s Levels

the five vertical levels of skin that are successively penetrated by an invading *melanoma. They are: epidermis, papillary dermis, intervening zone, reticular dermis, and subcutaneous tissue. They usually correlate with the *Breslow thickness. [W. H. Clark (1924–97), US dermatologist]... clark’s levels

Skin-grafting

An operation in which large breaches of SKIN surface due to wounding, burns or ulceration are closed by TRANSPLANTATION of skin from other parts. There are three methods by which this is done. Most frequently the epidermis only is transplanted, using a method introduced by Reverdin and by Thiersch, and known by their names. For this purpose, a broad strip of epidermis is shaved o? the thigh or upper arm, after the part has been carefully sterilised, and is transferred bodily to the raw or ulcerated surface, or is cut into smaller strips and laid upon it. A second method is for small pieces of the skin in its whole thickness to be removed from the arm and thigh, or even from other people, and then implanted and bound upon the raw surface. (This method has the disadvantage that the true skin must contract at the spot from which the graft is taken, leaving an unsightly scar.) When very large areas require to be covered, a third method is commonly used. A large ?ap of skin, amply su?cient to cover the gap, is raised from a neighbouring or distant part of the body, in such a way that it remains attached along one margin, so that blood vessels can still enter and nourish it. It is then turned so as to cover the gap; or, if it be situated on a distant part, the two parts are brought together and ?xed in this position until the ?ap grows ?rmly to its new bed. The old connection of the ?ap is then severed, leaving it growing in its new place.

Researchers are having success in growing human skin in the laboratory for grafting on to people who have been badly burned and have insu?cient intact skin surface to provide an autologous graft (one provided by the recipient of the graft). Other techniques being researched are the use of specially treated shark skin and the production of arti?cial skin.... skin-grafting

Cuticle

n. 1. the *epidermis of the skin. 2. a layer of solid or semisolid material that is secreted by and covers an *epithelium. 3. a layer of cells, such as the outer layer of cells in a hair.... cuticle

Dermis

(corium) n. the true *skin: the thick layer of living tissue that lies beneath the epidermis. It consists mainly of loose connective tissue within which are blood capillaries, lymph vessels, sensory nerve endings, sweat glands and their ducts, hair follicles, sebaceous glands, and smooth muscle fibres. —dermal adj.... dermis

Ecthyma

n. an infection of the skin caused by Streptococcus pyogenes, Staphylococcus aureus, and other bacteria. The full thickness of the epidermis is involved (compare impetigo, which is a superficial infection). Ecthyma heals slowly and causes scarring. It may be associated with poor hygiene or depressed immunity.... ecthyma

Ectoderm

n. the outer of the three *germ layers of the early embryo. It gives rise to the nervous system and sense organs, the teeth and lining of the mouth, and to the *epidermis and its associated structures (hair, nails, etc.). —ectodermal adj.... ectoderm

Tea For Sunburn

A sunburn represents a form of radiation burn. Its cause is the overexposure to ultraviolet radiation from the sun rays. The acknowledged symptoms are the following: red or reddish skin which is hot when touching, general fatigue and dizziness. Sometimes, sunburns can be life-threatening. Studies revealed that excessive UV radiation is a major cause of non-malignant skin tumors. How Tea for Sunburn works In general, teas for sunburn mitigate the feeling of skin irritation, calming the itching epidermis. Efficient Tea for Sunburn Cleavers tea and Irish Moss tea are proven to be effective teas for sunburn. Cleavers is a pasture plant originating from North America, Britain and Eurasia. It is well known for its clinging leaves that usually grow to a height of up to 2 meters and its sticky seeds, which attach themselves to anyone who passes by. Cleavers has bitter taste. For medicinally purposes, the whole plant is used. Cleavers can be taken in the form of tea, extracts, capsule, or fresh. To prepare Cleavers tea, infuse 2 to 3 teaspoons of the dried parts of the cleavers plant in a 250 mg cup of hot water. Allow the mixture to steep for about 10 to 15 minutes.  Cleavers tea can be drunk up to three times per day. Irish moss is a type of seaweed found on 6 inches high rocks, in the Northern Atlantic region. It is used to make a thickening agent for jellies, puddings, and soups. It is also found in drugs, foods, and toothpaste. It is also an ornamental plant, requiring very little maintenance. The Irish Moss seaweed can be eaten. To prepare Irish Moss tea, add 2 tablespoons of dried plant to a cup of hot water. Let the mixture steep for about 9-10 minutes. Strain it. The resulting beverage can be both drunk and applied topically. Tea for Sunburn: Side effects Teas for sunburn are not recommended to pregnant and nursing women. When in doubt what tea for sunburn fits best to your symptoms, ask the advice of your doctor.... tea for sunburn

Touch

The sense that enables an individual to assess the physical characteristics of objects – for example, their size, shape, temperature and texture. The sense of touch is considered here along with other senses associated with the skin and muscles. The cutaneous senses comprise:

Touch sense proper, by which we perceive a touch or stroke and estimate the size and shape of bodies with which we come into contact, but which we do not see.

Pressure sense, by which we judge the heaviness of weights laid upon the skin, or appreciate the hardness of objects by pressing against them.

Heat sense, by which we perceive that an object is warmer than the skin.

Cold sense, by which we perceive that an object touching the skin is cold.

Pain sense, by which we appreciate pricks, pinches and other painful impressions.

Muscular sensitiveness, by which the painfulness of a squeeze is perceived. It is produced probably by direct pressure upon the nerve-?bres in the muscles.

Muscular sense, by which we test the weight of an object held in the hand, or gauge the amount of energy expended on an e?ort.

Sense of locality, by which we can, without looking, tell the position and attitude of any part of the body.

Common sensation, which is a vague term used to mean composite sensations produced by several of the foregoing, like tickling, or creeping, and the vague sense of well-being or the reverse that the mind receives from internal organs. (See the entry on PAIN.)

The structure of the end-organs situated in the skin, which receive impressions from the outer world, and of the nerve-?bres which conduct these impressions to the central nervous system, have been described under NERVOUS SYSTEM. (See also SKIN.)

Touch affects the Meissner’s or touch corpuscles placed beneath the epidermis; as these di?er in closeness in di?erent parts of the skin, the delicacy of the sense of touch varies greatly. Thus the points of a pair of compasses can be felt as two on the tip of the tongue when separated by only 1 mm; on the tips of the ?ngers they must be separated to twice that distance, whilst on the arm or leg they cannot be felt as two points unless separated by over 25 mm, and on the back they must be separated by more than 50 mm. On the parts covered by hair, the nerves ending around the roots of the hairs also take up impressions of touch.

Pressure is estimated probably through the same nerve-endings and nerves that have to do with touch, but it depends upon a di?erence in the sensations of parts pressed on and those of surrounding parts. Heat-sense, cold-sense and pain-sense all depend upon di?erent nerve-endings in the skin; by using various tests, the skin may be mapped out into a mosaic of little areas where the di?erent kinds of impressions are registered. Whilst the tongue and ?nger-tips are the parts most sensitive to touch, they are comparatively insensitive to heat, and can easily bear temperatures which the cheek or elbow could not tolerate. The muscular sense depends upon the sensory organs known as muscle-spindles, which are scattered through the substance of the muscles, and the sense of locality is dependent partly upon these and partly upon the nerves which end in tendons, ligaments and joints.

Disorders of the sense of touch occur in various diseases. HYPERAESTHESIA is a condition in which there is excessive sensitiveness to any stimulus, such as touch. When this reaches the stage when a mere touch or gentle handling causes acute pain, it is known as hyperalgesia. It is found in various diseases of the SPINAL CORD immediately above the level of the disease, combined often with loss of sensation below the diseased part. It is also present in NEURALGIA, the skin of the neuralgic area becoming excessively tender to touch, heat or cold. Heightened sensibility to temperature is a common symptom of NEURITIS. ANAESTHESIA, or diminution of the sense of touch, causing often a feeling of numbness, is present in many diseases affecting the nerves of sensation or their continuations up the posterior part of the spinal cord. The condition of dissociated analgesia, in which a touch is quite well felt, although there is complete insensibility to pain, is present in the disease of the spinal cord known as SYRINGOMYELIA, and a?ords a proof that the nerve-?bres for pain and those for touch are quite separate. In tabes dorsalis (see SYPHILIS) there is sometimes loss of the sense of touch on feet or arms; but in other cases of this disease there is no loss of the sense of touch, although there is a complete loss of the sense of locality in the lower limbs, thus proving that these two senses are quite distinct. PARAESTHESIAE are abnormal sensations such as creeping, tingling, pricking or hot ?ushes.... touch

Epidermoid

adj. having the appearance of epidermis (the outer layer of the skin): used to describe certain tumours of tissues other than the skin.... epidermoid

Warts

Warts (verrucae) are small, solid outgrowths from the SKIN arising from the epidermis and caused by various subtypes of ‘human papilloma virus’. The causal viruses are ubiquitous and most people probably harbour them. Whether or not warts develop depends upon age, previous infection and natural resistance.

Common warts (verruca vulgaris) are seen mainly in children and young adults on the backs of the ?ngers and hands, and less often on the knees, face or scalp. They may be single or numerous and range from 1 mm to 10 mm or more in size. Untreated, they often resolve spontaneously after weeks or months. They may be occupationally contracted by butchers and meat-handlers.

Plane warts (verruca plana) are small, ?at-topped, yellowish papules seen mainly on the backs of the hands, wrists and face in young people. They may persist for years.

Digitate warts (verruca digitata) are ?nger- or thread-like warts up to 5 mm in length with a dark rough tip. They tend to grow on the eyelids or neck.

Plantar warts (verruca plantaris) occur on the soles of the feet, most commonly in older children, adolescents and young adults. Spread by walking barefoot in swimming pools, changing rooms, etc., these warts may appear as minor epidemics in institutions, such as schools. They are ?attened, yellow-white discrete lesions in the sole or heel, tender when squeezed. Multiple black points in the wart are thrombosed capillaries. Occasionally, aggregates of plantar warts form a mosaic-like plaque, especially in chronically warm, moist feet.

Genital warts are sexually transmitted. In the male they occur on the shaft of the PENIS and on the PREPUCE or around the anus. In women they occur around the entrance to the VAGINA and LABIA minora. Genital warts vary from 1–2 mm pink papules to ?orid, cauli?ower-like masses. Pregnancy facilitates their development.

Mucosal warts may develop on the mucous membranes of the mouth.

Laryngeal warts may be found in children whose mothers had genital warts (see above) at the time of delivery. Some subtypes of genital wart can infect the uterine cervix (see UTERUS), causing changes which may lead eventually to cancer.

Treatment CRYOTHERAPY – freezing with liquid nitrogen – is the principal weapon against all types of warts, but curettage (scraping out the wart with a CURETTE) and cauterisation (see ELECTROCAUTERY) or LASER therapy may be required for resistant warts. Genital warts may respond to local application of PODOPHYLLIN preparations. Sexual partners should be examined and treated if necessary. Finally, treatment of warts should not be more onerous or painful than the disease itself, since spontaneous resolution is so common.... warts

Aromatherapy

The external use of essential oils from seeds, resins, herbs, barks and spices for relaxant purposes.

Plant essences give plants their scent and were known to the ancient civilisations of Egypt and Greece as the ‘vital force’ or spirit of the plant. They were used for inhalation, rubbing on the skin or as a healthful addition to baths and foot-baths. The art is complementary to phytotherapy, acupuncture and other systems of alternative medicine.

The aromatherapist uses oils individually or in blends of different oils. The natural concentrated oil is usually diluted by adding a vegetable oil before direct application to the skin. A massage oil usually comprises 6 drops essential oil to 10ml (2 teaspoons) carrier oil – Almond, Peanut or other vegetable oil.

The skin is known to be an integral part of the immune system. T-cells are scattered throughout, primarily in the epidermis or outer layer. It has been demonstrated that oils rubbed on the skin are readily absorbed and borne to distant organs in the body via the bloodstream to soothe, relax and heal. Some oils should not be used during pregnancy or lactation.

An oil may be used as a natural perfume. As a bath oil, 5-6 drops of a favourite oil may be added to bathwater. Oils freshen a room; stimulate or relax as desired when added to water on a warm radiator. Oils are never used on the skin undiluted.

The aromatherapist never uses essential oils internally. Other carrier oils may be used: Sesame seed, Sunflower seed, Apricot kernel and Wheatgerm. Usual methods of applying essential oils: massage, inhalation and baths. When adding oils to baths water should not be too hot which causes oils to evaporate.

Remedies absorbed into the body via the skin avoid metabolism by the liver as when taken by mouth.

When the therapy was used in a geriatric ward in Oxford drug expenditure on laxatives and night sedatives fell. It was reported to have given profoundly deaf patients, many of whom had multiple sensory deficits, tranquillity. The results of a randomised trial in patients on an intensive care unit showed significantly greater psychological improvement (as demonstrated with anxiety and mood rating scales) in those given aromatherapy (1 per cent Lavender and Grapeseed oil) over those massaged with Grapeseed oil only or those prescribed rest alone. (The Lancet 1990 336 (8723) 1120)

The governing body of the therapy in the UK is the Aromatherapy Organisations Council (AOC) which represents the majority of professional practitioners. Enquiries: AOC, 3 Latymer Close, Braybrooke, Market Harborough. Leicester LE16 8LN. Tel/Fax 01858 434242. ... aromatherapy

Epitrichium

(periderm) n. the most superficial layer of the skin, one cell in thickness, that is only present early in embryonic development. It protects the underlying *epidermis until it is fully formed.... epitrichium

Keratinization

(cornification) n. the process by which cells become horny due to the deposition of *keratin within them. It occurs in the *epidermis of the skin and associated structures (hair, nails, etc.), where the cells become flattened, lose their nuclei, and are filled with keratin as they approach the surface.... keratinization

Keratinocyte

n. a type of cell that makes up 95% of the cells of the epidermis. Keratinocytes migrate from the deeper layers of the epidermis and are finally shed from the surface of the skin.... keratinocyte

Lentigo

n. (pl. lentigines) a flat dark brown spot found mainly in the elderly on skin exposed to light. Lentigines have increased numbers of *melanocytes in the basal layer of the epidermis (freckles, by contrast, do not show an increase in these cells). Lentigo maligna (preinvasive or in-situ melanoma) occurs on the cheeks of the elderly and has variable pigmentation.... lentigo

Burns

Tissue damage resulting from contact with heat, electricity, chemicals or radiation. Burns are classified according to the severity of damage to the skin. A 1st-degree burn causes reddening of the skin and affects only the epidermis, the top layer of the skin. A 2nd-degree burn damages the skin more deeply, extending into the dermis and causing blister formation. A 3rd-degree burn destroys the full skin thickness and may extend to the muscle layer beneath the skin. Specialist treatment, and possibly skin grafts, is necessary for 3rd-degree burns. Electrical burns can cause extensive tissue damage with minimal external skin damage. A 2ndor 3rd-degree burn that affects more than 10 per cent of the body surface causes shock due to massive fluid loss.

A burn is covered with a non-stick dressing to keep the area moist. If necessary, analgesic drugs are given, and antibiotic drugs are prescribed if there is any sign of infection. For extensive 2nddegree burns, when there may be slow healing or a fear of infection, a topical antibacterial agent such as silver sulphadiazine is used. Skin grafts are used early in treatment to minimize scarring. 3rd-degree burns always require skin grafting. Extensive burns may require repeated plastic surgery.... burns

Skeleton

The framework of bones that gives the body shape and provides attachment points for the muscles and underlying soft tissues of the body. The average human adult skeleton has 213 bones (counting each of the 9 fused vertebrae of the sacrum and coccyx as individual bones) joined with ligaments and tendons at points called joints. The skeleton plays an indispensable role inmovement by providing a strong, stable but mobile framework on which muscles can act. The skeleton also supports and protects internal body organs. skin The outermost covering of body tissue, which protects internal organs from the environment. Skin has 2 layers: the outer epidermis, and the inner dermis.

The outermost epidermis is composed of dead cells and the protein keratin. As these dead cells are worn away, they are replaced by new ones from the inner epidermis. Some epidermal cells produce the pigment melanin, which protects the body from ultraviolet light in sunlight.

The dermis is composed of connective tissue interspersed with hair follicles, sweat glands, sebaceous glands, blood and lymph vessels, and sensory receptors for pressure, temperature, and pain.... skeleton

Burn

n. tissue damage caused by such agents as heat, cold, chemicals, electricity, ultraviolet light, or nuclear radiation. A first-degree burn affects only the outer layer (epidermis) of the skin. In a second-degree burn both the epidermis and the underlying dermis are damaged. A third-degree burn involves damage or destruction of the skin to its full depth and damage to the tissues beneath. Burns cause swelling and blistering, due to loss of plasma from damaged blood vessels. In serious burns, affecting 15% or more of the body surface in adults (10% or more in children), this loss of plasma results in severe *shock and requires immediate transfusion of blood or saline solution. Burns may also lead to bacterial infection, which can be prevented by administration of antibiotics. Third-degree burns may require skin grafting. Small burns, or scars of previous burns, may be vital evidence of *child abuse.

burning mouth syndrome (BMS) a disorder characterized by a burning sensation in the mouth for which there is no obvious medical or dental cause. Other symptoms may include thirst, sore throat, and an unpleasant taste. BMS occurs most commonly in older females and may be related to menopause, stress, or vitamin deficiencies.... burn

Hair

n. a threadlike keratinized outgrowth of the epidermis of the *skin. It develops inside a tubular hair follicle. The part above the skin consists of three layers: an outer cuticle; a cortex, forming the bulk of the hair and containing the pigment that gives the hair its colour; and a central core (medulla), which may be hollow. The root of the hair, beneath the surface of the skin, is expanded at its base to form the bulb, which contains a matrix of dividing cells. As new cells are formed the older ones are pushed upwards and become keratinized to form the root and shaft. A hair may be raised by a small erector muscle in the dermis, attached to the hair follicle.... hair

Lichenification

n. thickening of the epidermis of the skin with exaggeration of the normal creases, thought to resemble tree bark. The cause is abnormal scratching or rubbing of the skin. It is one of the cardinal features of chronic eczema, together with erythema (flushing), pruritus (itching), and xerosis (dryness).... lichenification

Malpighian Layer

the stratum germinativum: one of the layers of the *epidermis.... malpighian layer

Milium

n. (pl. milia) a white nodule in the skin, particularly on the face. Up to 2 mm in diameter, milia are tiny *keratin cysts occurring just beneath the outer layer (epidermis) of the skin. Milia are commonly seen in newborn babies around the nose; they may disappear without active treatment. In adults they may be lifted out with a needle or removed by an abrasive sponge.... milium

Prickle Cells

cells with cytoplasmic processes that form intercellular bridges. The germinative layer of the *epidermis is sometimes called the prickle cell layer.... prickle cells

Squama

n. (pl. squamae) 1. a thin plate of bone. 2. a scale, such as any of the scales from the cornified layer of the *epidermis.... squama

Stratum

n. a layer of tissue or cells, such as any of the layers of the *epidermis of the skin (the stratum corneum is the outermost layer).... stratum

Nail

n. a horny structure, composed of keratin, formed from the epidermis on the dorsal surface of each finger and toe (see illustration). The exposed part of the nail is the body, behind which is the root. The whitish crescent-shaped area at the base of the body is called the lunula. Growth of the nail occurs at the end of the nail root by division of the germinative layer of the underlying *epidermis (which forms part of the matrix). The growing nail slides forward over the nail bed. The fold of skin that lies above the root is the nail fold; folds of skin on either side of the nail are the nail walls. The epidermis of the nail fold that lies next to the nail root is called the eponychium (forming the ‘cuticle’ at the base of the nail). Anatomical name: unguis.... nail



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