The Exchange of Gases in the Lungs The exchange of gases takes place in the alveoli 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 (среда) with a lower partial pressure iscalled diffusion. Hemoglobin is that substance of the blood which transfers oxygen in the blood. The oxygen capacity of the blood averages to 18-20 milliliters (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. Task 1. Answer the questions: 1. Where does the exchange of gases take place? 2. Where do oxygen and carbon dioxide pass into? 3. Where the partial pressure of oxygen is higher? 4. What is called Diffusion? 5. What is hemoglobin? 6. What is the oxygen capacity of the blood? 7. How is carbonic dioxide transferred? 8. What is called oxyhemoglobin? 9. What is carbohemoglobin? Task 2. Complete the sentences. Put the verbs in proper form: 1. On physical exertion the patient’s … become 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)

The exchange of gases takes place in the alveoli of the lungs. This means that oxygen passes from the alveoli into the bloodstream, and carbon dioxide passes from the bloodstream into the alveolar air.

1. Where does the exchange of gases take place?
The exchange of gases takes place in the alveoli of the lungs.

2. Where do oxygen and carbon dioxide pass into?
Oxygen passes into the blood, and carbon dioxide passes into the alveolar air.

3. Where is the partial pressure of oxygen higher?
The partial pressure of oxygen is higher in the alveolar air compared to the venous blood.

4. What is called diffusion?
Diffusion is the process of transfer of gases into a medium with a lower partial pressure. In this case, it refers to the movement of oxygen from the alveolar air into the blood, and the movement of carbon dioxide from the blood into the alveolar air.

5. What is hemoglobin?
Hemoglobin is a substance found in the blood that is responsible for transporting oxygen. It binds to oxygen molecules and carries them from the lungs to the tissues of the body.

6. What is the oxygen capacity of the blood?
The oxygen capacity of the blood refers to the maximum amount of oxygen that can be carried by the blood. On average, it is around 18-20 milliliters per 100 grams of blood.

7. How is carbon dioxide transferred?
Carbon dioxide is transferred in combination with hemoglobin and as bicarbonic salts. This means that some carbon dioxide binds to hemoglobin and some is transported as bicarbonate ions.

8. What is called oxyhemoglobin?
Oxyhemoglobin is the combination of hemoglobin with oxygen. When oxygen binds to hemoglobin, it forms oxyhemoglobin.

9. What is carbohemoglobin?
Carbohemoglobin is the combination of hemoglobin with carbon dioxide. When carbon dioxide binds to hemoglobin, it forms carbohemoglobin.

Task 2.

Complete the sentences. Put the verbs in proper form:

1. On physical exertion the patient's breaths become deep.
2. When the temperature is high, a patient usually breathes deeply.
3. When one breathes in, the lungs dilate.
4. When one breathes out, the lungs contract.