Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Physiology Part 2 > Lec 34 Ventilation and perfusion > Flashcards

Lec 34 Ventilation and perfusion Flashcards

1
Q

What makes up the conducting zone of respiratory system?

A
  • nose
  • nasopharynx
  • larynx
  • trachea
  • bronchi
  • bronchioles [terminal]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is function of conducting zone?

A

warm, humidify, and filter air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is structure of conducting zone?

A
  • contains mucus-secreting glands, cilia, smooth muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What makes up the respiratory zone of respiratory system?

A
  • respiratory bronchioles
  • alveolar ducts
  • alveolar sacs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Are terminal bronchioles part of conducting or respiratory zone?

A

conducting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are two functions of respiratory zone?

A
  • gas exchange

- surfactant production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is structure of respiratory zone?

A
  • elastic fibers

- epithelial cells [type I and II pneuomocytes]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is dead space?

A

the volume of airways and lungs that does not participate in gas exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is anatomic dead space? value?

A
  • volume of conducting airway

- 150 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is physiologic dead space?

A
  • the total volume of lungs [including airways] that does not participate in gas exchange
  • Physiologic dead space = anatomic dead space + functional dead space
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is functional dead space? What is reason for functional dead space

A
  • ventilated alveoli that do not participate in gas exchange

- due to mismatch of ventilation and perfusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the volume of anatomic dead space?

A

150 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is anatomic dead space made of?

A
  • nose/mouth
  • trachea
  • bronchi
  • non-respiratory [terminal] bronchioles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are low and upper limits of tidal breath normally?

A

150 mL to 500 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is tidal volume? How much of tidal volume participates in gas exchange

A

TV = 500 mL

350 mL participates in gas exchange, 150 mL is anatomic dead space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

In normal conditions what is relationship physiologic dead space and anatomic dead space?

A

normally physio dead space = anatomic
because functional dead space is minimal
due to good matching of ventilation and perfusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How do you measure physiologic dead space?

A
  • if dead space present, the air from dead space does not undergo gas exchange thus wil contain no CO2. air from exchanged alveoli will have CO2
  • measure difference between PCO2 from pure alveolar gas and PCO2 from expired air
  • lower PCO2 in expired air means it has been diluted by dead space
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

3 assumptions for measuring volume of physiologic dead space

A
  1. all CO2 in expried air comes from exchange of CO2 in functioning [V and Q] alveoli
  2. there is no CO2 in inspired air
  3. physiologic dead space contribute no CO2 since they don’t exchange gases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is equation for volume of dead space?

A

Vd = Vt * [PaCO2 - PeCO2]/PaCO2

Vd = volume dead space, Vt = tidal volume,  PaCO2 = arterial PCO2 [assumes this = alveolar]
PeCO2 = expired air PCO2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is equation for Vd/Vt?

A 
Vd/Vt = [PaCO2 - PeCO2] / PaCO2
a = arterial, e = expired
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is Vd/Vt with tidal volume 0.5 L, arterial blood gas 40 mmHg CO2, expired gas 28 mmHg CO2?

A

Vd/Vt = 0.33

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does Vd/Vt = 0 mean?

A
  • no physiologic dead space

- expired PeCO2 = arterial PaCO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does Vd/Vt = 1 mean?

A
  • physiologic dead space = tidal volume

- expired PeCO2 is zero so there is no gas exchange occuring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is minute ventilation?

A

Tidal volume [vol/breath] * RR [ breath/min]

Ve = Vt * RR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is normal tidal volume?
500 mL
26
What is normal respiratory rate?
12-14 breaths/minute
27
What is normal minute ventilation?
0.450 L * 14/min = 6.3 L/min
28
What are two equations for Ve [minute ventilation]?
Ve = TV * RR Ve = Vd [dead space ventilation] + V[A] [alveolar ventilation]
29
What are two equations for alveolar ventilation?
V[A] = (Vt - Vd)*RR alveolar V = (tidal vol - dead space ventilation) * respiratory rate V[A] = VCO2 * K / PACO2 alveolar V = rate of CO2 production * constant / alveolar PCO2 K = 863 mmHg for conditions of BTPS
30
What is the value of the constant in the equation V[A] = VCO2 * K / alveolar PCO2?
K = 863 mmHg for conditions of BTPS
31
What is equation for predicting alveolar PCO2?
VCO2 * 863 mmHg / Va ``` VCO2 = rate of CO2 production VA = alveolar ventilation ```
32
What kind of relationship is there between alveolar ventilation [VA] and alveolar PCO2 when rate of CO2 production is constant?
inverse relationship VA = VCO2 * K / PACO2
33
What is BTPS?
body temp 310 K ambient pressure 760 mmHg saturated water vapor
34
If VCO2 is constant, what determines PACO2?
VA = alveolar ventilation VCO2 = rate of CO2 production
35
What happens to VA when VCO2 is doubled in order to maintain PACO2?
VA is doubled to maintain normal value of PACO2
36
When VA is doubled, what happens to PACO2?
PACO2 is halved
37
What is the relationship between P[A]O2 and P[A]CO2? The equation?
P[A]O2 = PIO2 - PACO2/R ``` P[A]O2 = alveolar PO2 PIO2 = inhaled PO2 P[A]CO2 = alveolar PCO2 R = respiratory exchange ratio = CO2 production/O2 consumption ```
38
What is the respiratory exchange ratio [R]?
R = CO2 production / O2 consumption
39
What is normal level for respiratory exchange ratio [R]?
0.8
40
What happens to PACO2 and PAO2 if alveolar ventilation is halved?
PACO2 is doubled | PAO2 is more than halved
41
Are variations in PO2 or PCO2 higher between inspired air and mixed venous blood?
much greater variation in PO2
42
What are two things that vary among different regions of heart due to gravitational effects?
- regional blood flow [Q] | - alveolar ventilation [VA]
43
Where does FRC mostly reside in lung?
apex of lung
44
Where is ventilation highest?
the base of lung | -- because most potential space exists in base since apex is full with FRC
45
Where is Q [blood flow] highest in lung?
base
46
Where is V/Q highest vs lowest in lung?
lowest V/Q in bottom of lung | highest V/Q in top of lung
47
What is normal V/Q?
0.8
48
What is normal alveolar ventilation VA?
4 LPM [liters per minute] [4-4.8 to be exact]
49
What is normal lung perfusion [C.O.]?
5 LPM [5-6 to be exact]
50
What is normal PAO2?
100
51
What is normal PACO2?
40
52
When is V/Q = infinity?
when ventilation without perfusion = dead space
53
When is V/Q = 0?
when perfusion without ventilation = shunt
54
Are regional differences in ventilation or perfusion greater?
regional differences in perfusion are greater
55
What is ratio at base? ventilation at base? blood flow? PaO2? PaCO2?
``` ratio = 0.5 PaO2 = 89 mmHg PaCo2 = 42 mmHg ``` ventilation = 0.82 blood flow = 1.29
56
What is ratio at apex? ventilation at apex? blood flow? PaO2? PaCO2?
``` ratio = 3.0 PaO2 = 130 mmHg PaCO2 = 28 mmHg ``` ventilation = 0.24 blood flow = 0.07
57
Where is V/Q ratio highest? lowest?
highest in zone 1 = apex | lowest in zone 3 = base
58
Where is PaO2 highest? lowest?
highest in zone 1 = apex | lowest in zone 3 = base
59
Where is PaCO2 highest? lowest?
highest in zone 3 = base | lowest in zone 1 = apex
60
What are PaCO2 and PaO2 in pulmonary veins?
``` PaCO2 = 40 mmHg PaO2 = 100 mmHg ```
61
What is PaO2 and PaCO2 in pulmonary embolus / dead space?
``` PAO2 = 150 mmHg PACO2 = 0 mmHg ```
62
What is PAO2 and PACO2 in shunt/ airway obstruction / right to left cardiac shunt? What about PO2 and PCO2 in venous blood? V/Q?
``` PAO2 = none PACO2 = none - since no air flow PO2 venous = 40 PCO2 venous = 46 ``` V/Q = 0
63
What happens when high V/Q? What happens to PO2 and PCO2 in pulmonary capillary blood?
high ventilation relative to perfusion | blood has high PO2, low CO2
64
What happens when low V/Q? what happens to PO2 and PCO2 in pulmonary capillary bed? example of when this happens?
- low ventilation relative to perfusion --> due to deficient ventilation or excessive perfusion - blood has low O2, high CO2 - asthma attack
65
What happens to V/Q in pulmonary embolism?
V/Q = infinity
66
What happens to V/Q in airway obstruction?
V/Q = 0
67
What happens to V/Q in right to left cardiac shunt?
V/Q = 0
68
What happens to V/Q in asthma attack
low V/Q
69
What is normal atm PO2 and PCO2?
``` PO2 = 150 mmHg PCO2 = 0 ```
70
What is normal PO2 and PCO2 in pulm artery [aka before gas exchange]?
``` O2 = 40 CO2 = 45 ```

Physiology Part 2 (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions