HAIR

From Big Medical Encyclopedia

HAIR (pili) — the keratosic threadlike epithelial appendages of skin. Cover all surface of skin of the person, except for palms and soles, a dorsum of trailer phalanxes and a side surface of fingers, a red border of lips, nipples, small vulvar lips, the interior of big vulvar lips, a clitoris, a balanus, an internal leaf of a prepuce century.

Perform generally protective function century: at many animal species indumentum promotes preservation of heat in an organism, eyelashes protect eyes from bruises; thanks to the receptor nerve fibrils braiding a hair follicle, V. take part in tactile sensitivity (so-called voloskovy sensitivity).

Rudiments of hair follicles in the form of thickenings of embryonal epidermis are formed at the end of the 3rd month of embryonic development almost on all surface of a fruit. Then they turn into epithelial tyazh, to-rye get into a derma and in the depth of it are differentiated in the hair bulbs giving V. Vnachale V. growth appear in eyebrows, a chin and an upper lip, and on 5 — the 7th month — on many other sites of an integument of a fruit. On 8 — the 9th month of the embryonal period or in the first months of life of the newborn primary V.' most (excepting V. of the head, eyebrows and a century) drops out, being replaced new, secondary, or constants; primary vellus V. are replaced by more rough, and V. on the head, eyebrows and eyelashes as well longer. At newborn V. on the head have length apprx. 1 — 2 cm, their density is various; one-year-old children have not enough vellus V. At children of 2 — 4 years V. becomes more, and in 5 — 7 years their thickness and length, and also quantity of hair follicles increases. At newborns V.'s diameter is equal to 20 — 40 microns, at adult 70 — 100 microns.

In the period of sexual development V. in axillary hollows, on a pubis, generative organs appear; at young men V.'s growth on a breast, a back, hips begins, in 15 — 16 years V. on an upper lip, in 18 — 20 years — on a chin, cheeks, on a neck in front grow up.

After 50 years V.'s number, their thickness decrease, roots B. are shortened; many women have single long V. on an upper lip and on a chin. The elastic fibers surrounding roots B. are thickened, and by 70 years form the continuous weight surrounding a hair follicle.

In relation to the surface of skin of V. generally are located obliquely, under a different corner; eyelashes, V. of outside acoustical pass and the nasal courses are located perpendicularly. On all integument of V. have the certain directions generally matching Langer's lines (see. Skin ). As these lines on certain sites of skin (parietal area, around eyes and auricles, axillary and inguinal folds, side surfaces of a trunk) are spiral-shaped, V. in the specified areas form circulations or tufts. On the most part of a surface of skin of V. are located by groups (on 2 — 6), and their density is uneven. On the head V.'s number usually exceeds 100 000, the most dense V. — on parietal and occipital areas, less dense — on temporal area. Century of eyebrows more rare, even more rare V. on generative organs.

Color B. is various and depends on quantity and a type of a pigment of melanin. Dark V. (brunettes), chestnut (brown-haired persons) and fair-haired, blond (blondes) are more often observed. Less often red V. meet, this color is explained by existence of a ferriferous pigment of a trikhosiderin. Aged apprx. 50 years age usually begins canities (see), explained with gradual reduction in

V. of quantity of a pigment and filling cortical and marrow air traps. In the beginning more often the beard, moustaches, V. of cheeks, in 50 — 60 years — V. of the head, in 60 — 80 years — eyebrows turn gray.

Have the considerable durability and elasticity century. Speed of their growth during the different periods of life is various. Grow in chest and early children's age of V. slowly, at the adult in a month — apprx. 1 cm; after 60 years V.'s growth is slowed down. Quicker V. on the head, a chin, grow in axillary poles, more slowly — on forearms and hips. Eyebrows grow very slowly.

Each V. exists from several months to 4 years and more, then drops out and is replaced with new.

By outward and partly on a structure distinguish V. long, setaceous and vellus. Long V. are V. of a pilar part of the head, a beard, moustaches, axillary hollows, a pubis, generative organs; setaceous V. are hair of eyebrows, eyelashes, outside acoustical pass, a threshold of a nasal cavity, a circle of an anus; vellus V. cover other surface of skin. In a form B. there are straight lines curling, or wavy, and curly (small curls).

In a hair distinguish a core (scapus pili) acting over the surface of skin and the root (radix pili) which is located in the thickness of skin, terminating in a thickening — a bulb (bulbus pili).

Microscopic structure of a hair

In a root part of long and setaceous V. distinguish the following layers: marrow (core), bark B. and cuticle of Century.

Marrow B. (medulla pili) consists of 2 — 3 rows of the light cells of a polygonal form containing in protoplasm of a granule of trichohyaline, small air traps and a small amount of grains of a pigment. In marrow B. there is slow keratinization of cells; above the place of falling into a hair follicle of a channel of a sebaceous gland of a cell of V. completely orogovevat. In V.'s core, and also throughout vellus V. marrow is absent.

V.'s (cortex pili) bark consists of the multilayer cells of a spindle-shaped form which are strong soldered among themselves with signs of the mitoses disappearing in process of strengthening of a keratization and of the horn scales containing a firm keratin, grains of a pigment and air traps.

V.'s (cuticula pili) cuticle is formed by one number of flat thin nuclear-free horn scales, skintight to each other like a tile, the free edge to-rykh is turned up.

The root B. is put into V.'s (folliculus pili) follicle, or a hair sack, to-ry, extending to the surface of skin, forms a funnel. At the basis of a funnel in V.'s follicle the output channel of a sebaceous gland opens. Below the place of a confluence of a channel of sebaceous glands V.'s follicle is a little narrowed (a neck of a follicle).

From V.'s follicle, places of a confluence of a channel of a sebaceous gland are lower, smooth muscle fibers depart (mm. arrectores pilorum). Being fanlikely divided into small bunches, they come to an end in a top coat of a derma. At their reduction there is V.'s straightening, to-ry puts pressure upon a sebaceous gland that leads to the strengthened allocation of a secret.

V.'s follicle consists from internal epithelial and outside connective tissue parts. A connective tissue part of a follicle is formed tsirkulyarno and is longitudinal the located collagenic, elastic and argyrophil fibers. Its inner layer, shaped a thin homogeneous membrane, is most developed in the field of a hair bulb and carries the name of a vitreous cover or vitreous membrane.

In an epithelial part of a follicle distinguish an outside and internal root vagina. The outside root vagina is direct continuation of epidermis, to-ry loses a corneous layer since the place of a confluence of a sebaceous gland. In process of deepening of a root of a wall of an outside root vagina become thinner and at the basis of a follicle consist of cells of the same kind.

The internal root vagina is located between an outside root vagina and V.'s cuticle, directly adjoining to the last. In it distinguish: a periblast (stratum epitheliale pallidum, or Genle's layer) consisting of the nuclear-free cells of irregular shape extended along an axis of a hair of the same kind; the interlayer (stratum epitheliale granuliferum, or Gekeli's layer) formed by one-two rows of the semi-keratosic polygonal cells; a cuticle of an internal root vagina, the keratosic cells a cut are turned by free edge down, into depth of a follicle, closely adjoining to a cuticle of Century.

The root B. below extends, forming a hair bulb (bulbus pili). V.'s growth and an internal epithelial vagina happens by reproduction of the epithelial cells of a bulb creating a hair, i.e. the bulb is V.'s (matrix pili) matrix. From below the hair nipple (papilla pili) — the connective tissue formation of a cone-shaped form consisting of collagenic and elastic fibers, circulatory capillaries, nerves and melanocytes (star-shaped dofa-positive cells) presses in a hair bulb, to-rye form a hair pigment. Blood vessels of a hair nipple depart from a deep arterial texture of skin. The artery which is breaking up to a capillary network approaches each nipple then the post-capillary venules passing consistently into a deep veniplex of skin are formed. Walls of a follicle are supplied with blood from vessels of superficial network.

Fabric of a bulb represents accumulation strenuously of the breeding undifferentiated cells, on ultrastructure close to cells of a rostkovy layer of epidermis; according to a submicroscopy, in intracellular spaces of the central area of a matrix the cytoplasmatic shoots of melanocytes containing granules of a pigment are found.

In process of growth of a hair the size of a hair nipple gradually decreases, its functional activity decreases, cells of a bulb lose productive capacity and are exposed to keratinization. The bulb turns into a so-called hair flask and plunges into the formed deepening of a follicle — a hair bed; V.'s life on it stops. The flask separates from a nipple, together with V. gradually rises up and drops out. Further the follicle is shortened, and V.'s nipple rises, entraining a connective tissue vagina. (A microscopic structure of a hair — see tsvetn. fig. 1 — 4.)

V.'s regeneration begins with reproduction of cells of an outside root vagina, to-rye, covering a nipple, form a new bulb (matrix). In process of new V.'s growth the nipple falls deep into.

In the growing V. all cells, including and cells of an internal root vagina, have kernels in the beginning, then in process of removal from a hair bulb processes of keratinization amplify, cells lose kernels and turn into horn plates. Most intensively keratinization happens in cortical substance and V. V cuticle cells of these layers the firm keratin is formed, and process of its formation happens without intermediate stages of accumulation of eleidin and eleidin. The firm keratin which is the main substance B. differs in big density, is badly dissolved in water, is steady against many chemical substances, including acids and alkalis, contains a significant amount of amino acid — cystine. In marrow B., and also in an internal root vagina process of keratinization happens the same as in epidermis (the soft keratin is formed).

V.'s keratin — the proteic matter (scleroprotein) rich with sulfur (apprx. 4 — 5%) and amino acids (cystine apprx. 14, a leucine — 14, glutamic acid — 12, tyrosine — 3%). Contain also lipids (4 — 8%), cholesterol (0,1 — 0,2%), microelements century — manganese (44 — 74 mg of %), lead (22 — 42 mg of %), titanium (6 — 11 mg of %), copper (128 — 186 mg of %), silver (114 — 158 mg of %), aluminum (2,9 — 3,5 mg of %) and nek-ry enzymes, in particular the alkaline phosphatase influencing V.'s growth

Chemical structure of V. it is various depending on age and a sex of the person (e.g., in male V. contains sulfurs more, than in women's).

The nervous device of hair consists of one or several pulpy fibers suitable to a root B. and getting into a follicle places of a confluence of a sebaceous gland are lower. Having reached a vitreous membrane and having lost a pulpy cover, nerve fibrils form two types of trailer nervous devices here: the ring-shaped, covering hair follicle, and chastokolny, located in the depth of a follicle; both of them represent receptor educations.

V.'s growth is regulated by nervous and endocrine systems that is confirmed by clinical observations. Adrenocorticotropic hormone of a hypophysis, adrenal hormones, Thyreoidinum stimulate V.'s growth. V.'s growth is influenced by structure of food, pharmaceuticals (arsenic, vitamin A), and also physical. and chemical factors (ultraviolet rays, penetrating radiation); Grow quicker in warm season century.

Pathology of hair

Pathology of hair is observed as result of anomalies of development of V., dystrophic defeats, the general infectious diseases; strengthening or delay of growth of V. is observed at endocrine disturbances (acromegalias, a mix we go e, castrations); such pathology of V. as nek-ry forms of baldness, early canities, is caused, as a rule, by functional frustration of nervous, endocrine systems, etc. (tab. 1). V.'s pathology is observed also at V.'s defeat by parasitic fungi (tab. 2) and also as one of symptoms of nek-ry clinical syndromes (tab. 3). Separate diseases of hair, their prevention, treatment and the forecast — see. Alopecia , Microsporia , Moniletriks , Pilomikoz , Canities , Pseudopelade , Trichoclasia knotty , Trikhonodoz , Trichosporosis , Trichophytosis , Favus .

Hair in the medicolegal relation

Need in court. - medical examination arises in case as material evidences find hair.

Court. - medical examination can resolve a number of questions.

1. Whether the objects delivered for a research are hair? This issue is resolved macro - and microscopic examination. In doubtful cases investigate prints of a cuticle and cross sections of Century.

Fig. 1. Cuticle of a hair: 1 — the person; 2 — a silver fox; 3 — horses; 4 — goats.
Fig. 2. Core of a hair: 1 — the person; 2 — rats; 3 — goats; 4 — a rabbit.

2. The person or an animal possess V.? The signs distinguishing V. of the person from V. of animals come to light at a mikroskopirovaniye V.'s Edge of the person equal, with small stepped appearance, at V. of animals it uneven, with large teeth that is explained by an arrangement of cells of a cuticle (fig. 1). V.'s bark of the person makes his ground mass, at animals bark B. is thin, and the ground mass of V. is made by a core (marrow). Grains of a pigment in V. of the person small also do not form large accumulations, to-rye note in In, animal; grains of a pigment preferential in a peripheral part of a bast layer, and in V. of animals — in the central sites of bark B. and unevenly on length of a core are located. V.'s core of the person consists of small cells, densely adjacent to each other owing to what its structure does not come to light. Cells of a core of V. of animals have a certain system of an arrangement, between a core and bark there are pneumatic spaces that creates characteristic structure (fig. 2). At the person V.'s core, as a rule, does not exceed 1/3 thickness of V. (but 0,04 mm are not thinner), throughout V. can repeatedly be interrupted and have an appearance of separate islands; V.'s core of animals usually has an appearance of a continuous tyazh (except for a root and a top) uniform thickness. Unlike V. of the person, V.'s core of a number of animals during the processing by their alkali breaks up to disks.

Definition what animal possesses V., is based on features of a structure of their cuticle and core for what the studied V. compare to samples or tables of atlases of Century. For V.'s distinguishing the person and animals, except morfol. features of a structure of V., apply also the issue spectral analysis revealing various contents nek-ry macro - and microelements; investigate V. microchemical reaction to cystine.

Fig. 3. Cross sections of hair of the person: 1 — from a breast; 2 — from the head; 3 — from moustaches and a beard; 4 — from a pubis.

3. Definition of regional accessory of Century. For this purpose investigate length, a form and V. Tolshchina V. thickness of a beard of 0,143 — 0,166 mm, from area of generative organs of 0,126 — 0,153 mm, a breast — 0,122 — 0,125 mm, an axillary hollow — 0,101 — 0,119 mm, extremities — 0,094 — 0,101 mm, the head — 0,064 — 0,096 mm, vellus V. of a body — 0,020 mm. A form of cross section of V. (fig. 3) of the head — round and oval, V. of moustaches, beards, bakenbard and from nostrils — quite often triangular and polygonal, and a form of a cut of V. of a pubis reniform. The type of the ends of V. (the peripheral end never of short-haired V. is thinned iglovidno or it is metloobrazno split), specific imposings on hair and other features matter.

4. Similarity and possible origin of V. presented as material evidences from the different persons who are connected to the case are the most important issue for investigating and judicial authorities. For a research B., delivered as material evidences, take V. of different persons, from to-rykh their origin is supposed. The summary characteristic is made by the expert after studying of all macro - and microscopic signs of the studied V. Sravnivayut V., withdrawn from identical body parts; at the same time from the head take up to 15 — 20 hair from several sites (a forehead, a nape, the left and right temporal and parietal areas). Having made a comparative research, on the basis of summary characteristics establish a dissimilarity or V.'s similarity, but not identity since V. from the head of one person can differ among themselves, and V. of different people — to possess identical signs.

Recommend to investigate nek-ry chemical properties of hair, frequency of lines of the drawing of a cuticle, V.'s resistance on a gap, density, V.'s ability to change under the influence of high temperature, alkalis and other substances, the cross-sectional area of V., optical properties (photometry), V.'s luminescence, to conduct a gravimetric research, gistokhy. reactions, issue spectrographic research, neutron and activation analysis, etc. For the solution of a question of V.'s accessory to a certain person the research of maintenance of nek-ry chemical elements in V. at the persons occupied on certain productions is used (e.g., at zerkalshchik and photographers — silver), conduct an immunological research B., define antigens of the AB0 system and compare to a blood group of persons.

5. V.'s accessory to the man or woman. For this purpose investigate cells of a hair vagina for detection of little bodies Burra (see. Sex chromatin ). Detection of big percent of barpolozhitelny cells demonstrates that V. belongs to the woman; lack of barpolozhitelny cells or detection in a small amount tells them about V.'s accessory to the man. For sex determination studying of contents in V. nek-ry macro - and microelements is offered. The maintenance of microelements in V. is defined chemical, issue spectral, atomic and absorbing and other methods.

Fig. 4. Bulb of a hair: 1 — dropped out; 2 — pulled out.

6. The pulled-out V. differs from dropped out generally in a condition of a bulb. A bulb of the dropped-out V. the keratosic, dry, with smooth edges (fig. 4, 1); on its lower surface there is no deepening for a hair nipple. The bulb of the viable (pulled-out) V. consists of active cells, the lower surface has it deepening for a hair nipple, a part of a bulb can be absent (fig. 4, 2); on a root part of such V. the remains of vulval covers are noted. The pulled-out V. from dropped out can be distinguished by method of microchemical reactions.

Fig. 5. Some signs of the injured hair: 1 — it is torn off by the slow movement; 2 — it is completely polished; 3 — it is crushed; 4 — it is metloobrazno split; 5 — it is iglovidno thinned.

7. Character of the subject which caused damage to a hair, and a way of department of V. determine by features of the damaged site B. (fig. 5). Directly after a hairstyle of edge of a cut happen acute, to roughnesses, to-rye from combing and friction about clothes smooth out over time that gives nek-ry instructions on prescription of a hairstyle. Under the influence of high temperature of V. change color (brighten, and then ryzhet), in them air traps appear and they are twisted. At a temperature of 260 — 300 ° V. char. At shots at a short distance around a bullet wound of V. undergo a number of changes: are twisted, change color, the soot and poroshinka are postponed for them. V.'s damages

8 can put Poroshinki. For identification of the personality, and also for the solution of a question of V.'s accessory to a certain person there is a need for establishment of the fact of artificial discoloration of V. (coloring or decolouration). Discoloration of V. is observed also at the faces tied with certain productions (e.g., copper production). Artificial coloring is distinguished at microscopic examination of V. (paint is located unevenly on V.'s surface, a root part is not painted). It is recommended to apply issue spectral, luminescent analyses to establishment of the fact of artificial coloring of V., and also clarification of the nature of dye, etc. It is not always possible to distinguish the decoloured V. from light by the nature. The solution of this question is helped by a diazo test: the decoloured V. are painted by a diazoreactant in red color that is not observed at naturally light Century. Rotting changes color B.: dark V. become red-chestnut, and light — light brown.


Table 1. CLINICAL CHARACTERISTIC of BASIC DISEASES AND DAMAGES of HAIR

Table 2. CLINICAL CHARACTERISTIC of FUNGUS DISEASES of HAIR

Table 3. DAMAGE of HAIR AT SOME CLINICAL SYNDROMES

Bibliogr. Histology, under the editorship of V. G. Yeliseyev, etc., page 414, M., 1972; To and l and N of t and-evsky K. A. K to a question of development and morphology of hair at the person, Vestn, veins. and dermas.,№ 6, page 23, 1953; The Multivolume guide to a dermatovenereology, under the editorship of G. T. Pavlova, t. 2, page 50, L., 1961; Tu of ma-N about in A. K. Bases of forensic medical examination of material evidences, M., 1975, bibliogr.; it, Methods of a medicolegal research of hair, Court. - medical examination, No. 1, page 28, No. 2, page 23, 1972; Shabelnik D. Ya. About the maintenance of microelements in hair of the person depending on gender and age, in book: Microelements in medical, under the editorship of G. A. Babe.nko, century 1, page 184, Kiev, 1968; Dawber R. ampere-second about m an i s h S. Scanning electron microscopy of normal and abnormal hair shoffs, Arch. Derm., v. 101, p. 316, 1970; Fleck F. u. Fleck M. Die Haarkrankheiten des Menschen, B., 1962, Bibliogr.; Pinkus F. Die normale Anatomie der Haut, Handb. Haut-Geschl. - Kr., hrsg. v. G. Arndt u. a., Bd 1, T. 1, S. 1, B., 1927, Bibliogr.

O. K. Shaposhnikov; A. K Tumanov (court.), author of the tab. S. S. Kryazheva.

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