surface changes of the skin2

8/12/2019 Surface Changes of the Skin2

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SURFACE CHANGES OF THE SKIN

IntroductionThe skin is one of the largest organs in the body, having a surface area of 1,8

m2 and making up about 16% of body weight. t has many functions, the most

important of which is as a barrier to protect the body from no!ious e!ternal factors

and to keep the internal systems intact. "kin composed of threee layers# the

epidermis, the dermis and the subcutis. 1

Epidermis

The epidermis is an avascular, keratini$ed sheet of stratified suamous

epithelium. &ost epidermal cells are keratinocytes. "cattered among the keratinocytes

in the deepest epidermal layers are melanocytes, &erkel 'ells, and (angerhans cells.

)rom deep to superficial, the strata, or layers of the epidermis, are the basale,

spinosum, granulosum, lucidum, and corneum. The stratum lucidum is absent in thin

skin. The actively mitotic stratum basale is the source of new cells for epidermal

growth. The most superficial layers are increasingly keratini$ed and less viable.2

Dermis

The dermis, composed mainly of dense, irregular connective tissue, is well

supplied with blood vessels, lymphatic vessels, and nerves. 'utaneous receptors,

glands, and hair follicles resides within the dermis. The more superficial papillarylayer e!hibits dermal papillae that protrude into the epidermis above, as well as

dermal ridges, and the epidermal ridges that produce fingerprints. n the deeper,

thicker reticular layer, the connective tissue fibers are much more densely

interwoven. (ess dense regions between the collagen bundles produce cleavage, or

tension, lines in the skin. *oints of tight dermal attachment to the hypodermis

produce dermal folds, or fle!ure lines.2

Appendages Of Te S!in

"kin appendages, which derive from the epidermis, include hairs and hair

follicles, nails, and glands +sweat and sebaceous.2 1. "weat +"udoriferous -lands

ccrine +merocrine sweat glands, with a few e!ceptions, are distributed over the

entire body surface. Their primary function is thermoregulation. They are simple

coiled tubular glands that secrete a salt solution containing small amounts of other

solutes. Their ducts usually empty to the skin surface via pores.

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)igure 1. Cutaneous g"ands. +a photomicrograph of a sebaceous gland +16/!.

+b photomicrograph of eccrine sweat glands +20/!. 2

pocrine sweat glands, which may function as scent glands, are found primarily

in the a!illary and anogenital areas. Their secretion is similar to eccrine secretion,

but it also contains proteins and fatty substances on which bacteria thrive.

2. "ebaceous +il -lands

"ebaceous glands occur all over the body surface e!cept for the palms and soles.

They are simple alveolar glands3 their oily holocrine secretion is called sebum."ebaceous gland ducts usually empty into hair follicles.

"ebum lubricates the skin and hair, prevents water loss from the skin, and acts as

a bactericidal agent. "ebaceous glands are activated +at puberty and controlled by

androgens.

3. 4airs and 4air )ollicles

hair, produced by a hair follicle, consists of heavily keratini$ed cells. typical

hair has a central medulla, a corte!, and an outer cuticle and root and shaft

portions. 4air color reflects the amount and kind of melanin present.

hair follicle consists of an inner epithelial root sheath, enclosing the matri!

+region of the hair bulb that produces the hair, and an outer connective tissue root

sheath derived from the dermis. hair follicle is richly vasculari$ed and well

supplied with nerve fibers. rrector pili muscles pull the follicles into an upright

position and produce goose bumps.

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!cept for hairs of the scalp and around the eyes, hairs formed initially are fine

vellus hairs3 at puberty, under the influence of androgens, coarser, darker terminal

hairs appear in the a!illae and genital region.

)igure 2. Structure of a air and air fo""ic"e# +a 'ross section of a hair within

its follicle, diagrammatic view. +b *hotomicrograph of a cross section of a hair

and hair follicle +20/5. +c iagram of a longitudinal view of the e!panded hair

bulb of the follicle, which encloses the matri!, the actively dividing epithelialcells that produce the hair. +d *hotomicrograph of a longitudinal view of the hair

bulb in the follicle +16/5. 2

The rate of hair growth varies in different body regions and with se! and age.

ifferences in life span of hairs account for differences in length on different

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6. !cretion. "weat contains small amounts of nitrogenous wastes and plays a minor

role in e!cretion.

Homeostatic Im$a"ances of Te S!in

>hen skin rebels, it is uite a visible revolution. (oss of homeostasis in body

cells and organs reveals itself on the skin, sometimes in startling ways. The skin can

develop more than 1/// different conditions and ailments. The most common skin

disorders are bacterial, viral, or yeast infections. (ess common, but far more

damaging to body well7being, are skin cancer and burns.2

The study e!amined the skin of ?apanese children over 1/ years of age, i.e. at

the beginning of puberty, when physiological changes including active sebum

secretion begin to occur. Tokudome @ Tagami reported e!tremely low skin surface

hydration on the face and trunk in ?apanese children aged AB11 years, even compared

with the skin of elderly individuals, who are well7known to develop senile !erosis.

ur present biophysical data, obtained in children older than this, showed similar

results, i.e. the children<s skin showed a significantly low surface hydration state and

low levels of skin surface lipids. ven in normal adults, the dry and cold winter

season has a great influence on the skin condition, and affects the face more than the

forearm. 'linical observation revealed that appro!imately one7third of the children in

our study e!hibited visible dry skin changes in winter, in contrast to their mothers, the

maCority of whom did not show any dry skin in winter. >e found that the stratum

corneum +"' barrier function of the children, as assessed by trans7epidermal waterloss +T>( measurements, e!hibited distinct age7 and location7dependent

functional characteristics. n the fle!or forearm, the "' barrier function tended to

improve with increasing age, whereas it became poorer on the cheek of the older

children. "ebum e!cretion, which starts to occur on the cheek at around the age of 1A

years, worsens the poor facial "' barrier function by inducing the proliferation of

skin surface microflora, which may e!ert an irritating effect on the skin. 'ornified

envelopes +' is a thin insoluble structure enveloping corneocytes, and is formed via

transglutaminase7catalysed cross7linking of various precursor proteins, including

involucrin and loricrin. Thus, it provides a foundation for the organi$ation of the

intercellular lipids that are essential for the barrier function of the "'. The presenceof immature 's has been detected in the outermost layer of the "' of barrier7

impaired skin, including even normal facial skin. The ratio of immature 's on the

face does not depend on the age of the subCects +within the range 1/B0/ years, but it

increases during the winter season3 the ratio of immature 's in the children was

reported to be similar to that of adults. ur present results agree well with these

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findings. lthough it is not known why the ratio of immature 's in the 1A7year7old

age group tended to be higher than in other age groups, both children and adults, we

speculate that the start of high sebum e!cretion in the children in this age group maylead to mild inflammation, possibly due to the proliferation of surface microflora as

mentioned above. The skin surface hydration state of the children was remarkably

lower than that of the adults, as is clear from the development of dry skin in winter,

even on the face. t is well known that dry skin is observed in elderly persons in

winter. "uch senile !erosis is due to levels of skin surface lipids, intercellular lipids

and natural moisturi$ing factors +&), together with the retention of effete

corneocytes on the skin surface due to slower turnover of the "', reflecting the less

active epidermal proliferation in elderly individuals that is noted histologically as

atrophic epidermis +1A. n the present study, we also found similarly low skin

surface lipids in the children<s skin, reflecting lower production of all the components

of skin surface lipids.9

The ultraviolet component of solar light consists of :;= and :; parts,

which differentially penetrate the skin barrier and thus affect prevalently epidermal

+:;= or dermal +:; skin cells and corresponding e!tracellular structuresD

molecules. "kin surface lipids +""( play an important role for essential human skin

functions such as mechanical and chemical barrier, thermoregulation, and photo7

protection. (aying on the surface of the skin, ""( are also e!posed to the highest

doses of :;E:;= and they form the first7line defence against its potential danger.

&aCor photo7protective components of ""( are a7tocopherol and sualene+2,6,1/,10,1F,29,7he!amethyl72,6,1/,1A,18,227tetracosahe!aene, ", both working as

sacrificing antio!idants, since they block photo7induced lipid pero!idation in cellular

and acellular skin components, either by chain7breaking mechanism +a7tocopherol or

by uenching singlet o!ygen +". =oth are continuously produced by skin surface7

open sebaceous glands to maintain their physiologically essential levels and substitute

photo7destructed molecules. " is the most abundant o!idisable component of ""(,

its concentrations in adult human skin reaching up to 2/%, while its levels are

negligible in other organs. :pon action of environmental o!idants and microbial

residents of the skin, fast o!idative degradation of " occurs giving rise to a wide

spectrum of by7products, such as monohydropero!ides, epo!ides, and aldehydes.*hysiological doses of :; o!idise " at much higher rates than :;=. The role of

" and its o!idation products +"*! in skin photo7protection and in the induction of

inflammatory responses of keratinocytes in the conte!t of acne pathogenesis has been

evaluated and recently reviewed in.A

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burner and skin surface was 2B9 cm. 4yperthermia is variously defined as a body

core temperature higher than 9H.0B98.9I'. >hen the environmental temperature is

higher than the body, heat transmits into the body via conduction, convection, orradiation. The therapeutic effects of heat include +1 increased e!tensibility of

collagen tissues and +2 vasodilatation and increased blood flow to the affected area.

The increased rate of circulation acts to provide nutrients and o!ygen to promote

tissue healing. &o!ibustion is also used to regulate blood flow and i. "uperficial

hyperthermic temperature is skin temperature maintained at A/BA0I'. study by

driaensen et al showed that thermal stimulation of human skin at AA.0BA6.0I'

activated 7fibre mechano7heat7sensitive nociceptors. &ori et al showed that the

ma!imum temperature for indirect mo!ibustion was appro!imately 0/I'. nimal

studies of the thermal properties of indirect mo!ibustion show that the ma!imum

temperature induced by indirect mo!ibustion was about 60I' on the skin surface and

A0I' in the subcutaneous layer.2H !cessive heating can cause protein denaturation

and cell damage.6

"tem cells +"' are immature cells capable of self7renewal and development

to form speciali$ed cells of the body. The ability to provide a wide variety of cell

types makes "' an important reserve for the body in filling defects. *luri7and

multipotency properties of stem cells make them ideal for use in transplantation. t

should be borne in mind that in addition to the fact that stem cells, which migrate to

the $one of inCury or damaged tissues of the body +homing, also divide, and

differentiate, forming new cell types in the tissue +local "', fibroblasts, etc., as ifthey were Jcentral warehouse partsJ B stromal cells of organs# adipose tissue +T,

red bone marrow etc. n recent years, one line of stem cell B mesenchymal stem cells

+&"'s have found promising use in various aspects of cell therapy, including filling

of wound defects. &"'s are versatile cells3 they apparently are able to enter the

bloodstream into the affected organ or tissue and locally influenced by several

factors, give rise to speciali$ed cells, which replace the dead cells. t present, sources

of &"'s are adult red bone marrow, adipose tissue, blood, skin, etc. &"'s from

adipose tissue have been described not so long ago. n 2//2, merican scientists first

proposed the use of human adipose tissue as a source of multipotent stem cells.

"omewhat later, in 2//9, there were reports from ?apan about the prospects of clinicalapplication of &"'s from adipose tissue. -iven the fact that fat tissue in humans is

present in large uantity, a patient can be his own donor. This avoids immunological

incompatibility reaction. =one marrow tissue of humans and mammals is considered

as one of the preferred sources of &"'s. 4owever, the clinical use of bone marrow as

a source of &"'s is problematic, because the procedure is difficult, and as a result

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one can obtain only a small number of cells. ata of several authors indicate that

adipose tissue may serve as a source of cells that resemble bone marrow

mesenchymal stem cells, which posses the morphology of fibroblasts, reproduce invitro in standard medium, and are capable of multilineage differentiation. -iven that

the method of obtaining &"'s from adipose tissue compared with &"'s from bone

marrow or other tissues is easier and the number of cells obtained in the process is

more, we can hope for good prospects, for their use in medicine in the recovery of

damaged tissues.H

The use of &"'s of T in the treatment of infected wounds allows to uickly

restore the integrity of the skin, compared to traditional methods of treatment. The

regeneration of wound is greatly accelerated due to the ability of stem cells to

strengthen anti7inflammatory and regenerative processes. &"'s stimulate the

development epidermis, accelerate wound healing, and hence may improve cosmetic

outcome of treatment. The use of &"'s of adipose tissue for transplantation may

improve the treatment outcome of non7healing wounds in surgical practice.H

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DAFTAR %USTAKA

1. -awkrodger ?. &icroanatomy f The "kin. n# -awkrodger ?, 4orne T,

editors. ermatology n llustrated 'olour Te!t. 9rd ed. :K# 'hurchill

(ivingstone3 2//9. p. 2

2. &arieb , 4oehn K. The ntegumentary "ystem. n# &arieb , 4oehn K,

editors. 4uman natomy and *hysiology. H th ed. :"# *earson ducation, nc3

2//H.

9. kutsu , oguri &, nodera T, Kobayashi L, Katsuyama &, Kuni$awa , et al.

)unctional 'haracteristics f The "kin "urface f 'hildren pproaching *uberty#

ge and "easonal nfluences. cta erm ;enereol. 2//F3 8F# 2172H

A. Kostyuk ;, *otapovich , "tancato , e (uca ',(ulli , *astore ", Korkina (.

*hoto7!idation *roducts of "kin "urface "ualene &ediate &etabolic and

nflammatory Gesponses to "olar :; in 4uman Keratinocytes. *los ne ?ournal.

2/12

0. &eadow ?), =ateman ', 4erkert K&, <'onnor TK, -reen ?(. "ignificant'hanges n The "kin &icrobiome &ediated =y The "port f Goller erby. *eer?

?ournal. 2/19

6. (in (&, >ang "), (ee G*, 4su =-, Tsai &, *eng T'. 'hanges n "kin "urface

Temperature t n cupuncture *oint >ith &o!ibustion. =ritish &edical

?ournal. 2/19

H. "ahab 4, Tretyak ", ed$ved &K, =aranov ;, adyrov , (obanok 44, et al.

Gegeneration f "kin "urface =y &ultipotent &esenchymal "tem 'ells f

dipose Tissue in (aboratory nimals >ith nfected >ounds. &edicine "cience.

2/193 2+2# 6/171H

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surface changes of the skin2

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