ЛЕКЦИЯ № 24. Lung volumes and capacities

Lung volumes – there are four lung volumes, which when added together, equal the maximal volume of the lungs. Tidal volume is the volume of one inspired or expected normal breath (average human = = 0,5 L per breath). Inspiratory reserve volume is the volume of air that can be inspired in excess of the tidal volume. Expiratory reserve volume is the extra an that can be expired after a normal tidal expiration.

Residual volume is the volume of gas that re lungs after maximal expiration (average human = 1,2 L).

Lung capacities are comprised of two or more of the lung volumes. Total lung capacity is the volume of gas that can be con tained within the maximally inflated lungs (average human = 6 L).

Vital capacity is the maximal volume that can be expelled after maximal inspiration (average human = 4,8 L).

Functional residual capacity is the volume remaining in the lungs at the end of a normal tidal expiration (average luman = 2,2 L).

Inspiratory capacity is the volume that can be taken into the lungs after maximal inspiration following expiration of a normal breath. Residual volume can not be directly measured by spirometry. Because FRC and TLC include the residual capacity, they can not be directly measured by spirometry either. Helium dilution techniques are used to determine these capacities. A forced vital capacity is obtained when a subject inspires maximally and then exhales as forcefully and as completely as possible. The forced expiratory volume (FEV1) is the volume of air exhaled in the first second. Typically, the FEV1 is approximate 80% of the FVC. In obstructive lung diseases, such as bronchial asthma, the FEV1 is reduced much more that the FVC, producing a to FEV1 / FVC. In restrictive lung diseases, such as pulmonary fibro-sis, both the FEV1, and the FVC are reduced. This characteristically produces a normal or increased FEV1/ FVC.

GAS LAWS AS APPLIED TO RESPIRATORY PHYSIOLOGY: Dalton's Law: In a gas mixture, the pressure exerted by each gas is independent of the pressure exerted by the other gases.

A consequence of this is as follows: partial pressure = total pressure x fractional concentration. This equation can be used to determine the partial pressure of oxygen in the atmosphere. Assuming that the total pressure (or barometric pressure, PB) is atmospheric pressure at sea level (760 mmHg) and the fractional concentration of O2 is 21%, or 0,21: P02 = 760 mmHg ч 0,21 = 160 mmHg. As air moves into the airways, the partial pressures of the vari ous gases in atmospheric air are reduced because of the addi tion of water vapor (47 mmHg). Henry's Law states that the concentration of a gas dissolved in liquid is proportional to its partial pressure and its solubility coef ficient (Ks). Thus, for gas X, [X] = Ks ч Px

Fick's Law states that the volume of gas that diffuses across a barrier per unit time is given by:

Vgas = YxDx(P₁ – P₂)

where A and T are the area and thickness of the barrier, P₁ and P₂ are the partial pressures of the gas on either side of the barrier and D is the diffusion constant of the gas. D is directly proportional to the solubility of the gas and inversely proportional to the square root of its molecular weight.

New words

lung – легкое

volume – объем

equal – равный

the maximal – максимальный

tidal – вдыхаемый и выдыхаемый

inspired – вдохновленный

expected – ожидаемый

normal – нормальный

breath – дыхание

average – среднее число

human – человек

reserve – зарезервировать

residual – oстаточный

helium – гелий

dilution – растворение

techniques – методы

to be used to – использовать

to determine – определять

capacities – возможности

Поставьте слова в следующих предложениях во множественное число.

1. This room is very large.

2. There is a match in the box.

3. Has this lady a knife?

4. There is a man and a woman in the street.

5. This lady is that gen tleman's wife.

6. This shoe is too large for my foot.

7. The child is sitting on a bench.

8. My tooth is white.

9. This key is made of steel.

10. A potato is a vegetable and a cherry is a fruit.

11. This is my friend's study.

12. What is that child's name?

13. The cat has caught a mouse.

14. There was a lady, a gentleman, a boy and a girl in the room.

15. In the farm-yard we could see an ox, a sheep, a cow and a goose.

16. Is worker an Englishman or a German?

17. He is a Frenchman.

18. Why don't you eat this potato?

19. This strawberry is still green.

20. The withered leaf has fallen to the ground.

21. Can you see a bird in that tree?

22. Does your tooth still ache?

23. I held up my foot to the fire to warm it.

24. His child studies very well.

25. This man works at the office.

26. There is a new house in our street.

27. This story is very interesting.

28. I have hurt the foot.

29. The wolf has been shot.

30. He keeps his toy in a box.

31. Put this knife on that table.

32. I see a pupil.

Притяжательный падеж существительных / (Possessive case)

The child's toys – The children's toys

The boy's books – The boys' books

Перефразируйте следующие словосочетания и предложения, употребляя притяжательный падеж.

1. The room of my friend.

2. The questions of my daughter.

3. The wife of my brother.

4. The table of our teacher.

5. The poems of Shakespeare.

6. The voice of this girl.

7. The new club of the workers.

8. The letter of Pete.

9. The car of my parents.

10. The life of this woman.

Answer the questions.

1. How many lung volumes are there?

2. Are the lung volumes added together?

3. How can inspiratory reserve volume be inspired?

4. Can inspiratiry reserve volume be expired after a normal tidal expiration?

5. What is residual volume?

6. How are lungs capacities be composed?

7. Is vital capacity the maximal volume?

8. What is the functional residual capacity?

9. What is the inspiratory capacity?

10. Can residual volume be directly measured by spirometry?

Make the sentences of your own using the new words (10 sentences).

Make your own sentences using possessive case (10 sentences).

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) volume; b) head; c) lung;

2. a) air; b) breathing; c) hot;

3. a) stomach; b) bronchi; c) lungs;

4. a) nose; b) trachea; c) finger;

5. a) eye; b) alveoli; c) bronchi.