Phys- Ventilation/Lung Volumes

Question 1

5 steps of respiration

Answer 1

1. Ventilation
2. Diffusion of O2 and CO2 between alveoli and pulmonary capillaries
3. Transport of O2 and CO2 through pulmonary and systemic circulations via bulk flow (high to low pressure)
4. Diffusion of O2 and CO2 between blood and tissue
5. Cell utilization of O2 and production of CO2

Question 2

Tidal volume:

Definition and normal value

Answer 2

Volume of air inhaled and exhaled in one breath

500 ml

Question 3

Equation Vt

Answer 3

Vt = volume in alveoli + volume in airways

Question 4

IRV:

Definition and normal value

Answer 4

Max volume that can be inspired in addition to tidal volume

3 L

Question 5

ERV:

Definition and normal value

Answer 5

Max volume that can expired in addition to tidal vol

1.2 L

Question 6

Residual volume

Definition and normal value

Answer 6

Volume in lungs after max expiration

1.2 L

Question 7

FRC:

Definition and normal value

Answer 7

What’s left in lungs after NORMAL Vt; “equilibrium volume”

2.5 L

Question 8

FRC equation

Answer 8

ERV + RV

1.2L + 1.2L = 2.4L

Question 9

VC:

Definition and normal value

Answer 9

Volume expired after max inspiration

4.7 L

Question 10

VC equation

Answer 10

IC + ERV

Vt + IRV + ERV

Question 11

IC:

Definition and normal value

Answer 11

The maximal volume that can be inspired

3.5L

Question 12

IC equation

Answer 12

Vt + IRV

0.5+3 = 3.5L

Question 13

TLC:

Definition and normal value

Answer 13

All air in lungs

6 L

Question 14

TLC equation

Answer 14

VC + RV

Vt + IRV + ERV + RV = 0.5 + 3 + 1.2 + 1.2 = 6L

Question 15

FVC:

Definition and normal value

Answer 15

Volume of air forcibly exhaled after max inspiration

5 L

Question 16

FVC equation

Answer 16

Vt + ERV + IRV

0.5 + 1.2 + 3 = 4.7 L

Question 17

FEV1:

Definition and normal value

Answer 17

Volume of air forcibly expired in 1 sec

80% of FRC (2.5L), so 2L

Question 18

Three lung volumes/capacities NOT measured by spirometry

Answer 18

RV, FRC, TLC
(RV is the air left after max expiration, so it can’t be measured. Since RV is a component of TLC and FRC, they can’t be measured either)

Question 19

2 methods to measure RV, TLC, and FRC

Answer 19

He dilution and body plethysmography

Question 20

FEV1/FRC > 80%

Answer 20

Restrictive lung disease (can’t get air in so FRC decreases&raquo_space; FEV1)

Question 21

FEV1/FRC < 80%

Answer 21

Obstructive lung disease (can’t get air out, so FEV1 decreases&raquo_space; FRC)

Question 22

What is anatomic dead space? Normal volume?

Answer 22

Conducting airways where no gas exchange occurs due to lack of alveoli; 150 ml

Question 23

What are the conducting airways?

Answer 23

Trachea to terminal bronchioles

Question 24

What is alveolar dead space?

Answer 24

Alveoli that are ventilated but not perfused

Question 25

Increased alveolar dead space is always:

Answer 25

Pathologic

Question 26

What is physiologic dead space?

Answer 26

Sum of volume of anatomic and alveolar dead space

Question 27

How to estimate anatomic dead space

Answer 27

Lean weight in pounds

Question 28

When should you measure alveolar air?

Answer 28

End expiration; the air at the beginning of exhalation contains air from anatomic dead space which will have same composition as atmospheric air

Question 29

Minute ventilation equation

Answer 29

Vm = Vt * RR

Question 30

Normal Vm

Answer 30

Vm = 500 * 15 = 7500 ml/min

Question 31

Exercise Vm

Answer 31

Vm = 2000 * 20 = 40000 ml/min

Question 32

Vm at exercise:Vm at rest

Answer 32

40,000:7500 = 5.3 fold increase in Vm during exercise

Question 33

VA equation

Answer 33

VA = (Vt - Vds) * RR

Question 34

Normal VA

Answer 34

VA = (500 - 150) *15 = 5250 ml/min

Question 35

VA during exercise

Answer 35

VA = (2000 - 150) * 15 = 37,000 ml/min

Question 36

VA during exercise:VA at rest

Answer 36

37,000:5250 = 7 fold increase in VA during exercise

Question 37

Why does alveolar ventilation increase more during exercise than does minute ventilation?

Answer 37

Dead space decrease as a % of minute volume

Question 38

Which is more important for increasing alveolar ventilation: breathing rate or depth?

Answer 38

Depth (increase amount of air reaching alveoli)

Question 39

Normal pulmonary capillary blood volume

Answer 39

70 ml

Question 40

Px =

Answer 40

Px = Total pressure of mixture * % gas x in mixture | Dalton's Law

Question 41

Pressure =

Answer 41

F/A

Question 42

Normal atmospheric pressure

Answer 42

760 mmHg

Question 43

PAO2=

Answer 43

ALVEOLAR GAS EQUATION!! | PAO2 = PIO2 - PACO2/R

Question 44

R =

Answer 44

Respiratory quotient | CO2 produced/O2 consumed

Question 45

Normal R value? What does this mean?

Answer 45

0.8 | Changes in alveolar ventilation will affect O2 consumption more than CO2 production

Question 46

What happens to PAO2 when R decreases to 0.6?

Answer 46

Decreases | R decreased means O2 consumption increases and PACO2/R increases = decreased PAO2

Question 47

Pleural pressure of -4 = ___ mmHg

Answer 47

756

Question 48

Boyle's Law

Answer 48

P1V1 = P2V2 | pressure and volume are inversely related

Question 49

What determines air flow into or out of lungs?

Answer 49

Transrespiratory pressure

Question 50

Ptr =

Answer 50

Ptr = Palv - Patm

Question 51

What determines the inflation of the lungs?

Answer 51

Transpulmonary pressure

Question 52

Ptp =

Answer 52

Ptp = Palv - Pip

Question 53

___ pressure is always negative because:

Answer 53

Intrapleural; the chest wall wants to spring out while the lungs want to collapse, creating a negative pressure

Question 54

How do you measure intrapleural pressure?

Answer 54

Estimated using esophageal pressure

Question 55

When is transrespiratory pressure 0?

Answer 55

After a forced expiration/when breathing has stopped

Question 56

At the end of a forced expiration, intrapleural pressure is -4. What balances this?

Answer 56

Elastic recoil of lung