TOPIC. BLOOD AND ITS ELEMENTS. Study the new words.. Read the text. Pay attention to the new words for better understanding.. Text: Blood and its elements

TOPIC. BLOOD AND ITS ELEMENTS

2. Study the new words.

1. fluid connective tissue – жидкая соединительная ткань 2. cellular elements – клеточные элементы 3. platelets – пластинки 4. nucleus – ядро 5. lobe – доля 6. life span – продолжительность жизни 7. pierce the skin – прокалывать кожу 8. wound – рана 9. engulf the bacteria – поглощать бактерии 10. features – свойства 11. flexibility – гибкость 12. substance – вещество 13. erythrocytes-красные кровяные клетки 14. leukocytes –белые кровяные клетки 15. thrombocytes - тромбоциты

1.flu(ː)ɪd kəˈnɛktɪv ˈtɪʃuː 2.ˈsɛljʊlər ˈɛlɪmənts 3.ˈpleɪtlɪts 4.ˈnjuːklɪəs 5.ləʊb 6.laɪf spæn 7.pɪəs ðə skɪn 8.wuːnd 9.ɪnˈgʌlf ðə bækˈtɪərɪə 10.ˈfiːʧəz 11.ˌflɛksɪˈbɪlɪti 12.ˈsʌbstəns 13.ɪˈrɪθrəʊˌsaɪts 14. lukəʊˌsaɪts 15. θrombəʊˌsaɪts

3.Read the text. Pay attention to the new words for better understanding.

Text: Blood and its elements

Blood is a fluid connective tissue with many various functions. Many important physiological processes take place in the blood. It also determines the activity of separated body cells.

Blood is composed of plasma and the cellular elements. They are red blood cells (erythrocytes), white blood cells (leukocytes) and blood platelets (thrombocytes).

About 65 per cent of all white cells are leukocytes. Their protoplasm contains granules. One characteristic of leukocytes is the lobed appearance of the nucleus. The number of lobes is thought to be an index to the cell’s age. About 45 per cent of all leukocytes have a nucleus of three lobes. The life span of a leucocyte is short, from 4 to 12 days.

The function of leukocytes is to protect against infection. After the skin is pierced and the wound becomes infected, leukocytes from all the body are attracted to this place. Arriving at the wound, they leave the blood stream. They engulf the bacteria within their own protoplasm. This process is called phagocytosis.

Erythrocytes are the most numerous cellular elements. Red corpuscles have two physical features which are very important in the function of respiration. They have great elasticity and flexibility. These features give them the possibility to pass through very small capillaries. The most important part of the red cell is its red substance or hemoglobin.

The average human blood volume is not less than 7.5% but not more than 10% of the body weight.

Among the many specific functions of the blood are the following:

1. It transfers oxygen and carbon dioxide between the lungs and the body cells;

2. It carries from the digestive system the nutriments that cells need and gets rid of their waste products via the kidneys and other organs of excretion;

3. It carries hormones;

4. It helps regulate body temperature;

5. It provides substance that fight off infection.

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