Fig. 7. The formed elements of blood

4. Lymphocytes. These cells, which comprise about 35 per cent of the white cells, have a nucleus which practically fills the cell. They are produced in lymph nodes scattered throughout the body; the tonsils are examples of lymph nodes. They live only a few hours after they leave the blood stream. They are incapable of movement and thus cannot pursue bacteria and have little cytoplasm so that phagocytosis is practically out of the question, bacteria trapped in lymph node provoke the formation of themi Unfortunately if the infection is overwhelmig the lymph nodes themselves become infected. Thus in guinea pigs it has been pos­sible to trace the route of tubercle bacilli from the intestines to the lungs, as the route is marked by successively infected lymph nodes.

Notes

1. life span продолжительность жизни i

Упражнение 10. 1) Прочтите и переведите текст А. Абзац 3 переведите письменно. 2) Найдите в тексте А ответы на следующие вопросы.

1. What is the difference between neutrophils, basophils and eosino­phils? 2. When does the percentage of eosinophils increase? 3. The process of chemotaxis means «cell-eating», doesn't it? 4. What stimu­lates the formation of lymphocytes? 5. When do the lymph nodes be­come infected2 6. What kind of experiment is performed to prove this statement?

Упражнение il. Подберите пары синонимов.

ordinarily, primarily, to consist of, all over, about, chiefly, through­out, usually, approximately, to comprise

Lesson 7 ^ 105

* ■ Упражнение 12. Подберите пары антонимов.

regular, to arrive, usually, fortunately, to leave, irregular, unfortu­nately, unusually

Упражнение 13. Переведите следующие предложения с причастиями I и II.

1. One of the most important functions served by blood cells is the ingestion of foreign particles. 2. The blood is not the only fluid trans­porting material to different parts of the body. 3. The blood plasma contains among other things a soluble protein known as fibrinogen.

4. Blood and lymph are composed of cells dispended and carried within
a watery fluid. 5. Leucocytes are divided into two major types: granulo-
cytes, containing large granules in their cytoplasm and granulocytes
lacking granules in their cytoplasm.