Ventilation and Compliance 1,2/ Lung Volumes and Ventilation Flashcards

1
Q

what is the tidal volume (TV)?

A

the volume of air breathed out of the lungs at normal each breath (ex: between end of normal inspiration and end of normal expiration)

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

what is the expiratory reserve volume (ERV)?

A

the maximum volume of air which can be expelled from the lungs at the end of a normal expiration

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

what is the inspiratory reserve volume (IRV)?

A

the maximum volume of air which can be drawn into the lungs at the end of a normal inspiration

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

what is the residual volume (RV)?

A

the volume of gas in the lungs at the end of a maximum expiration

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

what is the vital capacity (VC)?

A

the tidal volume + the reserve volumes (IRV + ERV + TV). Basically the maximum tidal volume you can have

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

what is the inspiratory capacity (IC)?

A

the tidal volume + the inspiratory reserve volume (TV + IRV). Basically, starting from a resting point; the maximum air volume you can inhale

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

what is the functional residual capacity (FRC)?

A

the expiratory reserve volume + residual volume (ERV + RV). When resting, the volume which doesn’t move in an out (has functional role a residue?)

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

what is the FEV1?

A

the forced expired volume in 1 second (max you can expire in 1 sec)

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

what corresponds to FEV1/FVC?

A

the fraction of forced vital capacity expired in 1 second (max you can expire in 1 sec as a proportion of max you can expire in one go)

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

what is the anatomical dead space for the respiratory system? what’s its value?

A

corresponds to the volume of gas occupying the airways and this gas is not available for exchange, its value is 150mL

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

what does the term “ventilation” broadly refer to?

A

the movement of air in and out of the lungs (#breathing)

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

what is pulmonary ventilation?

A

total air movement into/out of lungs (relatively insignificant in functional terms), measured in L/min

“product of tidal volume and respiratory frequency”

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

what is alveolar ventilation?

A

fresh air getting to alveoli and therefore available for gas exchange (functionally much more significant), measured in L/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how do pulmonary and alveolar ventilation differ in value?

A
  • pulmonary ventilation = tidal volume

- alveolar ventilation = tidal volume - volume of anatomical dead space

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

what is the definition of partial pressure? (HINT: it’s about the pressure of a single gas in a mixture of multiple gases)

A

the pressure of a gas in a mixture of gases is equivalent to the percentage of that particular gas in the entire mixture multiplied by the pressure of the whole gaseous mix (expressed in mmHg or kPa)

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

under normal conditions, how do PO2 and PCO2 vary?

A

resting alveolar PO2 and PCO2 are fairly constant, because the percentage of oxygen in the atmosphere is constant

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

during hyper-ventilation, how do the partial pressures of O2 and CO2 vary?

A

increased alveolar PO2 rises and increased alveolar PCO2 decreases, because the percentage of oxygen in the lungs increases (to the detriment of the percentage of carbon dioxide), atmospheric pressure is still constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

during hypo-ventilation, how do the partial pressures of O2 and CO2 vary?

A

decreased alveolar PO2 decreases and decreased alveolar PCO2 increases, because the percentage of oxygen in the lungs decreases (to the benefit of the percentage of carbon dioxide), atmospheric pressure is still constant

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

NEW

what is the point of residual volume?

A

so the alveoli don’t collapse- it is easier to make them open up once they are already partially inflated (also gas exchange can happen all the time)

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

what is functional residual capacity?

A

air left in the lungs after a relaxed expiration

21
Q

when do the alveoli first expand?

A

first breaths of babies- difficult because fills the lungs’ residual volume

22
Q

how many types of dead space are there?

A

2- anatomical and

23
Q

what is the value of anatomical dead space?

A

average= 150 mL, is fixed for a certain lung size

24
Q

does hyper/hypoventilation mean too fast/slow respiratory rate?

A

no- it’s all about alveolar ventilation (breathing fast translates to hypoventilation unless you also breathe deeply)

25
Q

what is the value of normal alveolar ventilation?

A

4,2 L/min

26
Q

what is the value of normal partial pressure of alveoli?

A

13,3 kPa, 100 mmHg

27
Q

why is oxygen partial pressure different in the environment and the body?

A
  • inefficiency of breathing (dead space, dilutes the amount of oxygen)
  • residual volume (dilutes the amount of oxygen)
  • water added to it displaces some of the oxygen, dilutes it (the air is fully saturated, needs to be, so as to change state and diffuse)
28
Q

what is oxygen partial pressure in the environment?

A

160 mmHg

29
Q

if hyperventilation, what happens to oxygen partial pressure?

A

PO2 increases (oxygen accumulates) and PCO2 decreases

30
Q

if hypoventilation, what happens to oxygen partial pressure?

A

PO2 decreases and PCO2 increases (it is never expired, it accumulates). In hypoventilation, the body finds it extremely uncomfortable because of too much CO2 (not because of too little O2)

31
Q

NEW what is the point in reducing surface tension?

A

reduces tendency to collapse and close

32
Q

how is surface tension reduced?

A

surfactant molecules get between the water molecules reducing their forces of attraction to one another

33
Q

what is the difference between elasticity and compliance?

A

the ability to return to initial position is not a necessity in stretchability

34
Q

in which alveoli is surfactant more effective?

A

small alveoli because surfactant is more concentrated

35
Q

without surfactant, where would the air go?

A

the smaller alveoli would collapse because of stronger pressure pushing inwards, the air would flow into the larger alveoli, the surface area would be reduced

36
Q

what can be the cause of high compliance?

A

too loose, lack of elastine

37
Q

what can be the cause of low compliance?

A

difficult to stretch the lungs because of disease

38
Q

how does compliance vary with age?

A

compliance decreases with age, but low compliance = pathological, not physiological

39
Q

what force needs to be overcome during inspiration (especially at the beginning)?

A

surface tension and rib elasticity. (like blowing up a balloon, once you start there is tissue inertia which make it easier)

40
Q

what force needs to be overcome during expiration? why does expiration speed up (end of expiration faster than beginning)?

A

resistance of air inside the lungs. Speeds up because of elasticity

41
Q

when is expiration necessarily active?

A

in emphysema, where the loss of elastic tissue forces the lungs to force the air out by contraction

42
Q

what happens with fibrosis?

A

inert fibrous tissue, means more effort during inspiration because less compliance (not as steep on pressure/ volume graph)

43
Q

where in the lung is compliance greatest? why?

A

at the bottom side, because of gravity- the alveoli at the top stay more inflated than the ones at the bottom, even at the end of an expiration, so they can’t vary much (little compliance). The alveoli at the bottom are more compressed at the end of an expiration because of the weight of the rest of the lung, their range of variation is greater

44
Q

what is a normal FEV1/ FVC?

A

80%

45
Q

what is the effect of an obstructive disorder on compliance and FEV1/FVC ratio?

A

increased compliance, reduced ratio

46
Q

what is the effect of an restrictive disorder on compliance and FEV1/FVC ratio?

A

decreased compliance, similar ratio

47
Q

what might be a long term effect of obstructive disorders?

A

potentially higher FRC because residual volume accumulates and gradually builds up (as expiration does not tend to be complete)

48
Q

why look at absolute volumes in spirometry?

A

in restrictive disorders, FEV1/FVC might be normal, but the absolute volumes are much smaller