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Text B. The Exchange of Gases in the Lungs
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The exchange of gases takes place in the alveoli ['aelvialai] of the lungs. Oxygen passes into the blood and carbon dioxide passes into the atmospheric air.
The exchange of oxygen and carbon dioxide is due to the difference of partial (парциальное) pressure of these gases in the alveolar air and in the venous blood.
The partial pressure of oxygen in the alveolar air is higher than in the venous blood. The transfer of oxygen from the atmospheric air into the blood is due to this difference of pressures.
The partial pressure of carbon dioxide is higher in the venous blood and this enables carbon dioxide to pass from the blood into alveolar air.
The process of transfer of gases into the medium ['mildiam] (среда) with a lower partial pressure is called diffusion. Hemoglobin is that substance of the blood which transfers oxygen in the blood. The oxygen capacity of the blood averages to 18-20 millilitres (ml) per 100 gr of blood. Carbon dioxide is transferred in combination with hemoglobin and as bicarbonic salts.
The combination of oxygen and hemoglobin is called oxyhemoglobin, that of carbon dioxide and hemoglobin - carbohemoglobin.
LESSON 2O
HOME ASSIGNMENTS
I. А. Прочитайте предложение и ответьте на вопросы:
The man you see in the classroom teaches us Physiology.
1.* Найдите подлежащие и сказуемые в этом предложении. 2.* Сколько в нем предложений? 3.* Какая зависимость между этими предложениями? 4.* Что опущено между этими предложениями? 5.* Переведите предложение.
Б. Прочитайте и сравните следующие предложения:
а) I know my friend is not ill.
б) My friend you know well is not ill.
I. Определите виды придаточных предложений в (а) и (б) и скажите, как они соединяются с главным? 2. Как переводятся на русский язык бессоюзные придаточные предложения?
II. Определите виды придаточных предложений и переведите их:
1. We know well Servet was the first anatomist to describe the pulmonary circulation in the first half of the 16th century (1536-1538). 2. The phenomenon of the transfer of carbon dioxide from the blood into the lungs Sechenov investigated is due to the law of diffusion of gas from the fluid into the air.
3. The vital capacity of the lungs many physiologists have studied changes in some cardiac and pulmonary diseases. 4. The great English anatomist W. Harvey found out that the heart changed its colour during the contractions.
III. Выучите следующие слова и словосочетания:
associate [a'saujieit] v соединять; связывать; [a'saujnt] а объединенный;
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тесно связанный
passage ['passid3] n проход; проток
breathe [bri:Q] v дышать; breathe in вдыхать; breathe out выдыхать flow [fiao] n ток, течение; струя; v течь; циркулировать decrease [di:'kri:s] v уменьшать(ся); спадать; понижать(ся) depth [dep9] n глубина fat [faet] n жир; а жирный; упитанный amount [a'maunt] n количество
IV.* Переведите однокоренные слова:
associate, associated, associative, association; particular, particularly, particularity; change, changed, changing, changeable, exchange; connection, connective, connected; deep, deeply, depth
V. Вставьте недостающие по смыслу слова из данных ниже. Глаголы поставьте в соответствующей форме (письменно):
1. On physical exertion the patient's... became deep. 2. When the temperature is high a patient usually... deeply. 3. When one... the lungs dilate. 4. When one... the lungs contract.
breathe, breathe out, breath, breathe in
V. 1. Прочитайте текст С. 2. Найдите а) неопределенно-личные обороты и переведите их; б) Present Participle, определите его функции и переведите предложения. 3. Составьте пять вопросов к этому тексту.
4.Выпишите английские эквиваленты следующих словосочетаний:
имеет особое значение для, происходящий в легких, принимают участие в выработке
Text С. The Physiology of the Lungs
The physiology of the lungs is associated with their structure. There are over 700,000,000 alveoli in the lungs. The total surface of the alveoli is about 90 sq. m (square metres). The lungs have many capillaries with the total surface of about 80 sq. m. This particular structure of the lungs enables the exchange of gases between the alveolar air and the blood.
Elastic fibers of connective tissue composing the walls of the alveoli, alveolar passages and the visceral pleura enable the lungs to dilate.
When one breathes normally not all the alveoli and capillaries of the lungs are opened. When respiration becomes deep, the number of the opened alveoli and capillaries increases. The flow of blood into the lungs increases when one breathes in and it decreases when one breathes out.
The regulation of the vital capacity of the lungs is of particular importance to the exchange of oxygen and carbon dioxide taking place in the lungs. It is considered that in the adult the vital capacity of the lungs is about 3-4 litres. When the depth of respiration increases the vital capacity may be 6 litres and even more.
The lungs take part in the production of physiologically active substances, in the regulation of blood coagulation, in the metabolism of proteins, fats and carbohydrates.
CLASS ASSIGNMENTS
VII. Translate the following words. Find in them:
a ) suffixes: operate, various, regulation, changeable, appearance, importance, production, politician
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b) prefixes: discontinue, discovery, impossible, exchange, independent, disconnect, untreated, inattentive
VIII. Give the English equivalents of the words in brackets. Translate the sentences into Russian:
1. When we breathe out (ток) of blood into the lungs (уменьшается). 2. One of the mechanisms of headache (связан) with the pressure made by a tumour on the cranial and cervical nerves. 3. During the act of respiration the air enters the lungs through the air (ходы). 4. When the doctor was examining the patient he asked him (дышать) deeply. 5. (Жировые) substances which are located in the cell compose 1-2% of its total weight. 6. (Количество) of the fluid part of the blood called the plasma composes 60%.
IX. Read and translate the following sentences into Russian:
1. The treatment the patient had begun on the first of June was quite effective. 2. The condition of the patient we are treating has become better. 3. The methods of investigation the scientist had included in his research helped him to determine the origin of the pulmonary disease. 4. The faculty my brother is in trains pediatricians.
X. Complete the sentences choosing the appropriate clause:
1. The patient stated that... (a) he had had pneumonia two years before; b) he has pneumonia) 2. The doctor thought that... (a) the white blood cell count will be normal; b) the white blood cell count would be normal) 3. The scientists established that... (a) hemoglobin was the carrier of oxygen; b) hemoglobin is the carrier of oxygen)
XI. 1. Read Text D. 2. Entitle it. 3. Choose and translate indefinite personal sentences. 4. Say what the 2nd and 3rd paragraphs deal with:
Text D
If one investigates the act of inspiration (вдох) one will observe such phenomena.
When one breathes in, the external intercostal muscles contract and lift (поднимать) the ribs. At this moment the diaphragm also contracts and goes down. The volume of the chest increases. The increase of the chest volume enables the lungs to extend. The pressure in the lungs becomes less and the atmospheric air enters the lungs.
When one breathes out, the external intercostal muscles and the muscles of the diaphragm become relaxed (расслабленные). The ribs go down, the diaphragm goes up, the volume of the chest decreases and the lungs contract. The pressure in the lungs becomes higher and the air goes out of the lungs. If one is sitting or lying one makes 16-20 respirations per minute. On physical exertion the respiratory rate and the depth of respiration increase.
Normally during one inspiration the man breathes in about 500 ml of air. On deep inspiration one breathes in 1.5-2 litres of air.
The vital capacity of the lungs in the male averages 3.5-4 litres and in the female 3-3.5 litres.
The respiratory rate and its depth depend on the amount of carbon dioxide in the blood.
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