Pulmonary Ventilation and Gas Laws

Question 1

What are the inspiratory muscles

Answer 1

• respiratory diaphragm
• external intercostal muscles
• sternomastoids
• serratus anterior muscles
• scalene muscles

Question 2

What are the expiratory muscles?

Answer 2

Passive at rest
FORCEFUL muscles:
-abdominal muscles
-internal intercostals

Question 3

Define total lung capacity

Answer 3

maximum volume of gas that the lungs can hold

Question 4

Describe how volumes and capacities are related

Answer 4

combinations of lung volumes for lung capacities

Question 5

Define tidal volume; what is the value?

Answer 5

volume of air that is inspired or expired with each breath at rest
500 ml

Question 6

Define inspiratory reserve volume; what is the value?

Answer 6

Volume of air that can be inspired in addition to tidal volume with forceful inspiration
3000 ml

Question 7

Define expiratory reserve volume; what is the value

Answer 7

the additional volume of air that can be expired at the end fo tidal volume by forceful expiration
1100 ml

Question 8

Define residual volume; what is the value?

Answer 8

volume of air that is remaining in the lungs after forceful expiration 1200 ml

Question 9

What are the 4 types of pulmonary volumes?

Answer 9

tidal volume
Expiratory reserve value
inspiratory reserve volume
residual volume

Question 10

What are the 4 pulmonary capacities?

Answer 10

1. vital capacity
2. total lung capacity
3. inspiratory capacity
4. functional residual capacity

Question 11

Define vital capacity

Answer 11

The sum of all of the volumes that can be inspired or exhaled

inspiration to the max extent plus expiration to the maximum extent

4600 ml

Question 12

Define total lung capacity

Answer 12

the sum of all of the volumes

vital capacity+residual volume

5800 ml

Question 13

Define inspiratory capacity

Answer 13

the sum of the volumes above resting capacity= tidal volume +IRV

3500 ml

Question 14

Define functional residual capacity

Answer 14

the sum of the volumes below the resting capacity= ERV+ RV

2300 ml

Question 15

Define minute ventilation

Answer 15

the total volume of gases moved into or out of the lungs per minute= minute ventilation

Question 16

How is minute ventilation calculated?

Answer 16

breaths per minute X tidal volume
16 breaths a minute x 500 mL breaths
8000 ml/min

Question 17

Define alveolar ventilation

Answer 17

total volume of gases that enter the spaces participating in gas exchange per minute

Question 18

How is alveolar ventilation calculated?

Answer 18

breaths per minute x (tidal volume- dead space)

16 breaths per minute x (500 ml/breath - 150 ml/breath)
=5600 ml/min or 5.6L/min

Question 19

What is the anatomic dead space?

Answer 19

trachea, bronchi, bronchioles

Question 20

What is the physiological dead space?

Answer 20

anatomical dead space + ventilated alveoli with poor or absent perfusion

Question 21

What is the total dead space in a normal individual?

Answer 21

.15 L

Question 22

Describe the observations in calculating dead space and describe the equation that is used

Answer 22

Dead space does not participate in gas exchange and has negligible CO2

CO2 in lungs equals the arterial blood

VD = VTot X (PaCO2 ─ PECO2)/PaCO2

PaCO2 is the amount of CO2 in the arterial blood

PeCO2 is the amount of CO2 in the expired air

Question 23

Define pleural pressure

Answer 23

pressure of the fluid between parietal pleura and the visceral pleura

Question 24

Define alveolar pressure

Answer 24

pressure of the air inside the alveoli

Question 25

Define trans pulmonary pressure

Answer 25

difference between the alveolar pressure and the pleural pressure during any point of the inspiration or expiration cycles

Question 26

Is the alveolar pressure high with inspiration or expiration?

Answer 26

Higher with expiration

Question 27

Is the pleural pressure higher with inspiration or expiration?

Answer 27

higher with expiration

Question 28

Define compliance

Answer 28

the extent to which the lungs will expand for each unit increase in the transpulmonary pressure expressed in liters per centimeter of water measure of expansibility of the lungs and trachea also known as capacitance

Question 29

Describe how compliance and elastane differ

Answer 29

compliance the the measure of ease at which a hollow viscus may be distended elastane is the measure of the tendency of a hollow viscus to recoil toward its original dimensions

Question 30

Describe surface tension and state why this would be hazardous in the lungs

Answer 30

When water forms a surface with air, the water molecules on the surface have a strong attraction to each other; and they attempt to contract If this happened in the lungs, the alveoli would try to collapse creating a positive pressure in the alveoli

Question 31

What are the most important components of surfactant?

Answer 31

1. dipalmitoylphosphatidylcholine 2. surfactant apoproteins 3. calcium ions

Question 32

Where is surfactant produced?

Answer 32

type 2 alveolar cells

Question 33

What happens to the pressure in the alveoli if there is no surfactant

Answer 33

If there is no surfactant, the pressure would be about 18 cm of water pressure compared to the normal 4, which is about 4.5x as great

Question 34

Describe the components of air in the atmospheric pressure and give the percentages of each component

Answer 34

N-78.09% O2- 20.95% CO2- 0.03%

Question 35

What are the percentages of the components of air that are within the alveoli which is saturated with 6/18% water vapor?

Answer 35

N- 73.26% 02- 19.65% Ar- 0.87% CO2- 0.03%

Question 36

Define Dalton's law

Answer 36

the total pressure exerted by the mixture of non-reactive gasses is equal to the sum of the partial pressure of individual gasses

Question 37

Define Boyle's law

Answer 37

For a fixed amount of an ideal gas kept at a fixed temperature, P and V are inversely proportional

Question 38

Define henry's law

Answer 38

At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid

Question 39

What is the ideal gas law

Answer 39

P=nRT/V

Question 40

What are the partial pressures of O2 and CO2 at the alveolar membrane?

Answer 40

O2- 150 mmHg | CO2- 0.21 mmHg

Question 41

Describe the relationships between pressure and rate of diffusion and the concentration of gas molecules in the alveoli

Answer 41

Pressure is directional proportional to the concentration of the gas molecules rate of diffusion is directly proportional to the pressure caused by that gas alone

Question 42

What are the solubility values of O2 and CO2 and what does this difference do to the partial pressure?

Answer 42

``` O2= 0.024 CO2 = 0.57 ``` Co2 is more soluble which means that it will exert a higher partial pressure

Question 43

Define vapor pressure

Answer 43

Vapor pressure of water is the partial pressure exerted to escape the liquid phase form the gas phase

Question 44

What is the vapor pressure at a normal body temperature?

Answer 44

47 mmHg

Question 45

What is the relationship between temperature and vapor pressure?

Answer 45

Directly proportional

Question 46

What are the factors that affect the rate of gas diffusion in a fluid?

Answer 46

- solubility of gas in the fluid - cross sectional area of the fluid - distance through which the gas must diffuse - molecular weight of the gas - temperature of the fluid