innervation of adrenergic fibers. These glands do not begin to function until puberty.
Sebaceous glands are simple, branched holocrine acinar glands. They usually discharge their secretions onto the hair shaft within hair follicles. These glands are found in the dermis throught the skin, except on the palms and soles.
Secretory portions consist of peripherally located, flattened stem cells that resemble basal keratinocytes. Toward the center of the acini, enlarged differentiated cells are engorged with lipid. Death and fragmentation of cells nearest the duct portion result in the holocrine mechanism of secretion.
Duct portions of sebaceous glands are composed of stratified squamous epithelium that is continuous with the hair cat and epidermal surface.
Functions involve the lubrication of both hairs and cornified layers of the skin, as well as resistance to desiccation.
Control of sebaceous glands is hormonal. Enlargement of the acini occurs at puberty.
Hairs are long, filamentous projections consisting of dead keratini-zed epidermal cells. Each hair derives from an epidermal invagination called the hair follicle, which possesses a terminal hair bulb, located in the dermis or hypodermis, from which the hair shaft grows. Bundles of smooth muscle cells, called arrector pili muscles, are attached to the hair follicle at one end and the papillary dermis at the other. Contraction of these muscles raise the hairs and dimple the epidermis («goose flesh»). The follicles and associated sebaceous glands are known as pi- losebaceous units.
Nails, like hair, are a modified stratum corneum of the epidermis. They contain hard keratin that forms in a manner similar to the formation of hair. Cells continually proliferate and keratinize from the stratum basale of the nail matrix.
New words
cutaneous – кожный
appendace – покров
coiled – намотанный
tubular – трубчатый
widely – широко
to distribute – распространять
columnar-like – колоночноподобный
pyramidal – пирамидальный
surface – поверхность
duct portions – части трубочки
corkscrew-shaped – имеющий форму штопора
luminal – люминал
thermal – тепловой
innervation – иннервация
abundant – в изобилии
to facilitate – облегчать
Часто, при первом упоминании предмета, тем не менее не рекомендуется перед ним употреблять определенный артикль:
1) если упоминаемый предмет является единственным в мире:
Е. g. The sun is shining brightly;
2) если этот предмет является определенным по ситуации:
Е. g. Put the book on the table.
Вставьте артикль, где необходимо.
1. What's… weather like today? -… weather is fine.
2… sun is yellow.
3… sky is grey today.
4… earth is… planet.
5. We had… English lesson yesterday… teacher asked me many… questions… questions were difficult.
6. Where is your… brother? – He is at… home. He is in his… room. He is sitting at… table. He is doing his… homework… homework is difficult.
7. Our… cat is sitting on… sofa.
8. It is very dark in… room. Turn on… light, please.
9. Nick went into… bathroom, turned on… water and washed his hands.
10. This is… good… book. Take… book from… table. Put this… book into… bookcase.
11… weath er is fine today… sky is blue… sun is shining brightly in… blue… sky.
12. This is… boy… boy is… school. He is… pupil.
13. This… boy is my… brother's friend.
14. He has… cat, but he has no. dog.
15. He likes his…cat.
16. He gives. cat… milk every day.
17. Yesterday I received… letter from my… friend… letter was interesting.
18. We live in… big house. I like… house very much.
19. Are you. worker? – No, I am… student.
20. Is this… table? – Yes, this is a table.
Answer the questions.
1. What are all derivatives of the epidermis?
2. What do secretory portions consist of?
3. How much do secretory portions extend?
4. What are duct portions composed of?
5. In what regulation are glands important?
6. What is surrounded by myoepithelial cells?
7. What is the result in the holocrine mechanism of secretion?
8. What are duct portions of sebaceous glands composed of?
9. What does each hair derive from?
10. What contain hard keratin?
Make the sentences of your own using the new words (10 sentences).
Find the definite and indefinite articles in the text.
Find one word, which is a little bit different in meaning from others (найдите одно слово, которое немного отличается от других по смыслу):
1) a) cutaneous; b) skin; c) face;
2) a) cold; b) heat; c) thermal;
3) a) mouth; b) nose; c) arm;
4) a) nail; b) hair; c) skin;
5) a) neck; b) head; c) string.
ЛЕКЦИЯ № 6. Matter
Matter is anything that occupies space, possesses mass and can be perceived by our sense organs. It exists in nature in three, usually inter convertible physical states: solids, liquids and gases. For instance, ice, water and steam are respectively the solid, liquid and gaseous states of water. Things in the physical world are made up of a relatively small number of basic materials combined in various ways. The physical material of which everything that we can see or touch is made is matter. Matter exists in three different states: solid, liquid and gaseous. Human senses with the help of tools allow us to determine the properties of matter. Matter can undergo a variety of changes – physical and chemical, natural and controlled.
Chemistry and physics deal with the study of matter, its properties, changes and transformation with energy. There are two kinds of properties: physical – colour, taste, odour, density, hardness, solubility and ability to conduct electricity and heat; in solids the shape of their crystals is significant, freezing and boiling points of liquids.
