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UNIT 3

THE STRUCTURE OF THE SKIN

The skin is composed of two main layers: a thin outer layer, known as the epidermis and a thicker inner layer, called the dermis.

The epidennis, a protective layer without blood vessels and nerves, is built up of fiat cells of the epithelium. The cells of the epidermis reproduce themselves rapidly in its deepest layer and move up to the surface where they form aprotective layer of dead cells. These dead cells are continually being lost and replaced by new ones. This process is known as keratinization. The body produces and loses a great amount of these epithelial cells every day. The cells of the epidennis contain pigment, melanin which gives the skin the colour. The hereditary faętors decide whether the skin is lighter or darker in colour, and also sunlight causes the iricrease in melanin concentration, which protects the skin from harmful ultraviolet sun rays. In certain parts of the body the epidermis is modified to produce hair and nails. Hair grows on all the body surface, except the palms of the hands and soles of the feet.

Fig. 3. The strucluro ofthe skin.

The dermis, which consists mainly of elastic connective tissue, is much thicker than the epidermis. A network of blood vessels, lymph vessels andnerves runs through the dermis. The dermis forms lineśfćharacteristic for each person, called. fmgerprints. The dermis contains the glands, such as sweat glands, mammary glands, and sebaceous glands which produce oil to make the skin and hair elastic. Below the dermis, there is a layer of subcutaneous tissue, which contains mainly the fat.

EXERCISE A. Answer the following ąuestions.

1.    What are the names of the main layers of the skin?

2.    What is the epidennis madę up of?

3.    Where are the epidennal cells produced?

4.    What tissue is the dermis composed of?

5.    What structures does the dermis contain?

6.    What lies below the dermis?

E. Donesch-Jcżo — English for Medical Students and Doctors — 1

Word List

•    blood vesscl ['bUd ,vesal]

-    naczynie krwionośne

•    conncctive tissue [ka'nektiv 'tisju:]

-    tkanka łączna

•    dermis ['da:mis] — skóra

właściwa

•    epidermis [,epi'd3:mis]

-    naskórek

•    epithelium [,cpi'0i:li3m]

-    nabłonek

•    fiat [fiat] - płaski

•    hair [hcD] - włosy

•    keratinization [.ker3tini'zcijan]

-    kcratynizacja,

rogowacenie

•    layer flcia] - warstwa

•    mammary gland ['mamsrfgland]

-    gruczoł mleczny

•    melanin ['melanin]

-    melanina (barwnik)

■ nail [neil] - paznokieć

•    sebaceous gland [si'bcijDs'gland]

-    gruczoł łojowy

•    skin [skin] - skóra

•    sole [soul] — podeszwa

•    subcutaneous [,SAbkju:'teinias]

-    podskórny

•    sweat gland ['swet'gland]

- gruczoł potowy

•    tough [t^Af] - mocny,

wytrzymały

£XERCISE