Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BMS 242 - CVS respiratory > Respiration II > Flashcards

Respiration II Flashcards

1
Q

What is the total ventilation?

A

The volume of air moved in and out of the lungs PER UNIT OF TIME

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

What is the total ventilation at normal resting conditions?

Why?

A

6 litres/min

Total ventilation = tidal volume x breathing frequency

At resting conditions:

  • Tidal volume = 0.5
  • Breathing frequency = 12
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is anatomical dead space?

What part of the respiratory system is this?

A

The space NOT INVOLVED in gas exchange

Conducting zone

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

How much of the total volume is in the conducting zone?

A

30%

~0.15litres

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

How big is the average breath?

How much of the breath is from the conducting zone?

A

500ml

150ml

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

Why does the conducting air zone impact on gas exchange?

A
  • Not the same composition as ‘fresh’ air

- Impact on the composition of the air in the alveoli

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

What is ‘alveolar ventilation’?

How is it calculated?

A

The volume of ‘fresh’ air reaching the respiratory zone

Total ventilation - dead space ventilation

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

What is the alveolar ventilation?

A

4.3litres/min

6litres/min - (0.15x12)

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

What does ventilation rate impact on?

A

Alveolar and arterial gas COMPOSITION

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

How much CO2 does the body make per minute?

A

200ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

At steady breathing rate, what is the volume of the alveoli?

What does this cause the partial pressure in the alveolar to be?

A

Volume - 4.2L

Partial pressure 40mmHg

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

What happens if double ventilation rate?

A
  • Body still makes 200ml of CO2 but in a 8.4L
  • Partial pressure of the alveoli goes DOWN
  • CO2 content of the blood DECREASES
  • Alkalosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens if half ventilation rate?

A
  • Body still makes 200ml of CO2 but in a 2.1L
  • Partial pressure of the alveoli goes UP
  • CO2 content of the blood goes UP
  • CO2 content of the blood INCREASES
  • Acidosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does the lung ventilation vary?

Why does it vary?

A

Varies according to the position in the lung:
At the base = higher ventilation

Due to:

  • Posture
  • Gravity
  • Starting volume of the alveoli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the changes in the intrapleural pressure in the lungs?

Why?

A

Apex:

  • More NEGATIVE
  • Lungs PULLING down

Base:

  • More POSITIVE
  • Lungs PUSHING down
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the properties of the apex of the lung

A
  • HIGH transpulmonary pressure
  • Alveoli have a HIGH starting volume (large alveoli)
  • DILUTED surfactant
  • LOW compliance
  • HARDER to expand alveoli
  • Lower ventilation
  • Lower perfusion
  • Higher v/p ratio
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe the properties of the base of the lung

A
  • Alveoli have a SMALL starting volume (small alveoli)
  • HIGH LEVELS of surfactant
  • HIGH compliance
  • EASIER to expand alveoli
  • Higher ventilation
  • Higher perfusion
  • Lower v/p ratio
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does LOW compliance mean?

A

SMALL changes in pressure - SMALL changes in volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does HIGH compliance mean?

A

SMALL changes in pressure - LARGE changes in volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is perfusion?

A

BLOOD FLOW to the lung

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Does the pulmonary circulation operate at higher or lower pressures than than the systemic circulation?

A

LOWER

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

What are alveolar vessels?

A

Capillaries and slightly larger vessels that are SURROUNDED on all sides by the alveoli (travel THROUGH the alveoli)

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

What is the resistance in the alveolar vessels linked to?

A

TransMURAL pressure of the vessels and LUNG VOLUME

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

What is transmural pressure?

A

Difference in pressure between 2 sides of the wall or equivalent boundary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What does the resistance of the alveolar vessels increase?

How?

A

When INSPIRE:

1) Alveoli EXPAND more
- Slightly COLLAPSES the blood vessels and reduces the DIAMETER of the vessels

2) Also STRETCHES the vessels, reducing the diameter

26
Q

What are the extra-alveolar vessels?

A

Vessels that are NOT surrounded by the alveoli

27
Q

What is the resistance in the extra-alveloar vessels linked to?

A

IntraPLEURAL pressure

28
Q

What happens to the resistance in the extra-alveolar vessels when breath in?

A

Intrapleural pressure becomes MORE NEGATIVE

  • Transmural pressure of the vessels INCREASE
  • Vessels EXPAND
29
Q

What happens to the resistance in the extra-alveolar vessels when breath out?

A

Intrapleural pressure becomes MORE POSITIVE

  • Transmural pressure of the vessels DECREASE
  • Vessels are RESTRICTED
30
Q

What is the total pulmonary resistance the sum of?

A

Alveolar and extra-alveolar resistances

31
Q

When is the total pulmonary resistance at the lowest?

A

When the lungs are at functional residual capacity:

  • Alveoli aren’t expanded (pressure of 0)
  • Pressure in the intrapleural space is subatmospheric (Expansion of the chest wall balances the collapse of the lung)
32
Q

What does a positive transmural pressure cause?

A

The airways to expand - inspire

33
Q

What does a negative transmural pressure cause?

A

The airways to constrict - expire

34
Q

How can the pulmonary circulation accommodate increases in pulmonary pressure and flow rate?

What does this do?

A

By RECRUITMENT of more and more capillaries:

Reduces system resistance

35
Q

What does the recruitment of capillaries in the pulmonary system depend upon?

A

The pressure head forcing the blood through the vessels

36
Q

What is the reference point for pulmonary circulatory pressures?

A

Outside of the heart, level with the left atrium

37
Q

What is Ppa?

What is the mean value?

A

Pressure in the pulmonary ARTERIOLES

15mmHg (20 cmH2O)

38
Q

What is Pva?

What is the mean value?

A

Pressure in the pulmonary VENULES

8mmHg (10 cmH2O)

39
Q

What is Pva or Ppa affected by?

How?

A

Height above or below the lungs:
- FALL by 1cm H2O for every 1cm ABOVE the left atrium

  • INCREASE by 1cm for every 1cm BELOW the left atrium
40
Q

What is Pa?

A

Alveolar pressure (relative to the atmosphere)

41
Q

When is Pa 0? (relative to the atmosphere)

A

When there is no difference between atmospheric an alveolar pressure
(No movement of air)

42
Q

What happens to the flow rate through the vessels as drop down through the lung?

Why?

A

Increases as get to the level of the heart

  • Increase in transmural pressure - eventually becomes positive
  • Expansion of the blood vessels
  • Higher perfusion rate
43
Q

What does a positive transmural pressure mean?

A

The pressure in the alveoli is GREATER than that in the intapleural space

44
Q

What happens to the resistance in flow in the lungs below the heart level? (zone 4)

Why?

A

Increased resistance

Even though the transmural pressure expands the capillaries:
- Interplural pressure causes contraction of the alveolar vessels

45
Q

What is intraplural pressure normally?

A

Less than atmospheric

46
Q

What happens if the intrapleural pressure becomes positive?

A

Lung collapse will occur

47
Q

What 3 things alters perfusion?

A
  • Alveolar CO2 level
  • Alveolar O2 level
  • Interstitial pH
48
Q

What is hypoxia?

What does it cause?

A

Decreased O2 in the alveoli or increases CO2 in a region

Causes:

  • Constriction of the blood vessels (opposite to the systemic circuit)
  • Acidification (increased CO2 - fall in pH)
49
Q

What is the ventilation/perfusion ratio?

A

Ratio of the RATE of alveolar ventilation and pulmonary blood flow

Ratio = ventilation/perfusion

50
Q

What does the ventilation/perfusion ratio influence?

A

Gas composition

51
Q

What happens if the alveoli are not ventilated?

How does this affect gas composition in the alveoli?

A
  • Ventilation is 0
  • Ratio is 0

Gas composition will reach EQUILIBRIUM with MIXED VENOUS BLOOD

  • 40 mmHg O2
  • 46 mmHg CO2
52
Q

What happens if the alveoli are not perfused?

How does this affect gas composition in the alveoli?

A
  • Perfusion is 0
  • Ratio is infinite

Gas composition will reach EQUILIBRIUM with INSPIRED HUMIDIFIED AIR

  • 149 mmHg O2
  • OmmHg Co2
53
Q

What is the composition of the air at the apex of the lungs?

A

Closer to the composition of the atmospheric air

54
Q

What is the composition of the air at the base of the lungs?

A

Closer to the composition of the mixed venous blood

55
Q

What makes the final composition of the blood that goes into the systemic circulation?

A

The blood from both the APEX and the BASE

56
Q

What should the anatomical and physiological dead space be?

A

The SAME

57
Q

What happens if there is an increase in the physiological dead space?

What can cause this?

A
  • Part of the lungs aren’t being perfused properly
  • Ratio to infinity
  • Gas composition becomes the same as inspired air

Caused by pulmonary embolism

58
Q

What is the compensation mechanism for a reduction in perfusion due to a pulmonary embolism?

A
  • Blood REDIRECTED to other areas
  • Bronchiolar CONSTRICTION (redivert air)

Reduction is SURFACTANT production:

  • Reduction in COMPLIANCE
  • Harder to inflate alveoli
59
Q

Why is surfactant production decreased when the lungs are poorly perfused?

A

Minerals are needed to make surfactant

These minerals are carried in the blood

60
Q

What is a pulmonary shunt?

What can cause this?

A
  • Local reduction in VENTILATION (but the perfusion remains the same)
  • Composition of gas becomes the same as mixed venous blood
  • Ratio becomes 0

Caused by foregin body in the airways

61
Q

What is the compensation mechanism for pulmonary shunt?

A
  • Air directed to other parts of the lungs
  • Reduced O2 in TRAPPED air
  • Pulmonary VASOCONSTRICTION

BMS 242 - CVS respiratory (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions