Final Exam: Lab 8 Respiratory Physiology

Question 1

What is another term for pulmonary ventilation?

Answer 1

breathing

Question 2

Define pulmonary ventilation in simple terms.

Answer 2

The exchange of air between the atmosphere and the lungs

Question 3

What causes pressure within a gas sample?

Answer 3

Pressure is caused by gas molecules striking the walls of a container

Question 4

Define Boyle’s Law

Answer 4

The pressure of a gas is inversely proportional to the volume of its container.

Increase Vol = Decrease pressure
Decrease Vol = Increase pressure

Question 5

How is the volume of the thoracic cavity changed?

Answer 5

. By muscle contraction and relaxation.

Question 6

What happens to pressure when we increase the volume within the thoracic cavity and the
lungs?

Answer 6

Pressure decreases

Question 7

What is the pressure within the lungs called?

Answer 7

15. Intrapulmonary, or intra-alveolar, pressure

Question 8

What is the value of intrapleural pressure compared to intrapulmonary (alveolar) pressure?

Answer 8

20. Intrapleural pressure is always less than intrapulmonary (alveolar) pressure.

Question 9

What three factors cause the intrapleural pressure to be less than intrapulmonary (alveolar)
pressure?

Answer 9

21. (1) The surface tension of the alveolar fluid.
    (2) The elasticity of the lungs.
    (3) The elasticity of the
    thoracic wall.

Question 10

Why does a lung collapse if you cut into the pleural cavity?

Answer 10

25. Because the pressure of the intrapleural cavity becomes equal to atmospheric pressure. There is no
    longer less pressure in the intrapleural cavity compared to within the alveoli so the lung collapses.

Question 11

a. What is the transpulmonary pressure? b. What is the function of the transpulmonary
pressure?

Answer 11

26. a. The difference between the intrapleural and intrapulmonary pressures.
    b. It creates the suction to
    keep the lungs inflated.

Question 12

If a pneumothorax occurs in one lung, why doesn’t it also occur in the other lung?

Answer 12

27. Each lung has its own pleural cavity and pleural membranes so that changes in the intrapleural
    pressure of one lung do not affect the other lung.

Question 13

) Match the pressures to their definition:
• Intrapulmonary Pressure
• Transpulmonary Pressure
• Intrapleural Pressure
a. The pressure within the pleural cavity.
b. The pressure within the alveoli.
c. The difference between the pressure within the
pleural cavity and the pressure within the
alveoli

Answer 13

29. a. Intrapleural Pressure b. Intrapulmonary Pressure c. Transpulmonary Pressure

Question 14

Chose the proper words to explain what happens during inspiration.
The diaphragm and external intercostal muscles __________ (contract, relax).
↓
The volume of the thoracic cavity _________ (increases, decreases).
↓
Intrapleural pressure becomes ________ (more, less) negative.
↓
Lungs ________ (recoil, expand).
↓
Intrapulmonary pressure __________ (increases, decreases).
↓
Air flows _________ (into, out of) the lungs.

Answer 14

31. contract, increases, more, expand, decreases, into

Question 15

Chose the proper words to explain what happens during inspiration.
The diaphragm and external intercostal muscles __________ (contract, relax).
↓
The volume of the thoracic cavity _________ (increases, decreases).
↓
Intrapleural pressure becomes ________ (more, less) negative.
↓
Lungs ________ (recoil, expand).
↓
Intrapulmonary pressure __________ (increases, decreases).
↓
Air flows _________ (into, out of) the lungs.
Air flows _________ (into, out of) the lungs.

Answer 15

32. relax, decreases, less, recoil, increases, out of

Question 16

What two factors play roles in ventilation besides muscle contraction?

Answer 16

34. (1) The resistance within the airways

(2) Lung compliance.

Question 17

What is airway resistance due to?

Answer 17

35. The gas molecules encountering resistance as they strike the walls of the airway.

***Diameter of airway

Question 18

What happens to the airway resistance as the bronchiole constricts?

Answer 18

36. As the diameter of the walls of the bronchiole decrease, the resistance increases

Question 19

Does histamine constrict or dilate bronchioles?

Answer 19

constricts

- increase airway resistance –> decrease airflow

Question 20

Does epinephrine constrict or dilate bronchioles?

Answer 20

dilates

- decrease resistance –> increase airflow

Question 21

What two factors is lung compliance dependent upon?

Answer 21

40. (1) The stretchability of the elastic fibers within the lungs. (2) The surface tension within the alveoli.
    .

Question 22

What happens to alveoli when there is not enough surfactant?

Answer 22

41. Alveoli have high surface tension, and they tend to collapse
    - Surfactant = decrease ST and increase lung complaince

Question 23

Intrapulmonary pressure changes

Answer 23

pressure with in lungs

Question 24

What causes intrapulmonary pressure changes

Answer 24

atmospheric pressure, inspiration, expiration

Question 25

what are the results of the intrapulmonary pressure changes

Answer 25

1. atmospheric pressure = 760mmHg 2. inspiration = 1 mmHg below atmospheric pressure 3. expiration = 1 mmHg above atmospheric pressure

Question 26

*****Events during inspiration

Answer 26

Increase volume o thoracic cavity --> intrapulmonary pressure below atmospheric pressure = negative pressure Airflow into the lungs End of inspiration -> when intrapulmonary pressure equals atmospheric pressure = airflow stops

Question 27

**** events during expiration

Answer 27

- decrease volume of thoracic cavity -> intrapulmonatry above atmospheric pressure airflow out of the lungs -> end of expiration -> intrapulmonary equals atmospheric pressure

Question 28

Other factors affecting ventilation | - resistance

Answer 28

the diameter of airway (epi and hisptamine stuff) airflow = (pressure/resistance)

Question 29

how is resistance affected by changes in airway diameter

Answer 29

increase airflow -> decrease diameter -> increase resistance because more gas molecules encounters airway wall

Question 30

how does increased resistance affect air flow

Answer 30

- (histamine constricts) | - increase airway resistance = decrease airflow

Question 31

factors affecting airway resistance

Answer 31

histamine and epinephrine

Question 32

lung compliancc

Answer 32

- ease with which the lungs expand

Question 33

amount of elastic tissue

Answer 33

strethability of elastic fibers with in the lungs

Question 34

surface tension

Answer 34

- intermolecular forces within fluid molecules that attract molecule to each other

Question 35

Tidal volume

Answer 35

volume of air inhaled or exhaled in a single unforced breathe

Question 36

inspiratory reserve volume

Answer 36

- difference between volume at end of normal inhalation and vital capacity

Question 37

expiratory reserve volume

Answer 37

difference between volume at end of normal exhalation and vital capacity

Question 38

vital capacity

Answer 38

maximum volume of air that can be moved into the lungs

Question 39

residual volume

Answer 39

volume remaining in lungs after a maximum of expiration

Question 40

total lung capacity

Answer 40

total amount of gas in lungs after a maximum inspiration

Question 41

the spirogram shows relationship among various values.. total lung capacity = vital capacity =

Answer 41

total lung capacity= vital capacity + Residual volume vital capacity = Expiratory reserve volume + TV + IRV

Question 42

spirometry in lab

Answer 42

spirometers in lab are instruments that can only measure exhaled volumes. only able to measure VC, TV, and ERV IRV = VC - (TV + ERV)

Question 43

Total minute volume

Answer 43

total volume of air moved in and out of the lungs in one minute. this value is the product of the ventilation rate (number of breaths per minute) and the tidal volume (ml of air per breathe)

Question 44

When oxygen diffuses across the alveolar walls, most of the oxygen becomes bound to

Answer 44

hemoglobin

Question 45

the percent exyhemoglobin saturation is

Answer 45

the percentage of hemoglobin molecules that have 4 oxygen molecules attached. - this value indicates the effectiveness of gas exhange

Question 46

gas exhange occurs by

Answer 46

diffusion, any abnormal conditionthat changes the rate of diffusion will change the percent oxyhemoglobin saturation

Question 47

pulse oximeter

Answer 47

- an instrument that can measure percent oxyhemoglobin saturation continuously

Question 48

would oxyhemoglobin saturation value change during exercise?

Answer 48

increase exercise -> (increase temp/decrease pH) -> increase 02 delivery to muscles because hb affinity for O2 decreases, therefore increases unloading of O2