Brainscape's Knowledge GenomeTM

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


See full index

respiratory system year 1 > ventilation and compliance > Flashcards

ventilation and compliance Flashcards

1
Q

define tidal volume

A

TV
500ml
the volume of air breathed in/out of the lungs at each breath
only uses a fraction of our lung capacity

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

define expiratory reserve volume

A

ERV
1.1L
the max vol 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

define inspiratory volume

A

IRV
3L
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

define residual volume

A

RV
1.2L
the volume of gas in the lungs at the end of a normal expiration
cannot be voluntarily moved out and remains in the alveoli

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

what is the purpose of RV

A

important for gas exchange to continue at all times between breaths
helps prevent the alveoli collapsing (requires much more effort to inflate the alveoli from a collapsed state rather than a partially inflated state)

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

define vital capacity

A 
VC
4.5L
TV + IRV + ERV
max amount of air you can move on one breath 
good value to use in lung function tests
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

define total lung capacity

A

TLC

VC + RV

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

define inspiratory capacity

A

IC

TV + IRV

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

define functional residual capacity

A

FRC
ERV + RV
volume of air left in the lungs after a normal expiration

requires a greater change in pressure from FRC to reach a particular lung volume during inspiration than to maintain that volume during expiration

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

define forced expired volume in 1s

A

FEV1

4.0L in healthy, fit, young adult males

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

define fraction of forced VC expired in 1s

A

FEV1:FVC
FVC in healthy young males = 5L
FEV1/FVC = 80%
absolute values decline slightly with age

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

define anatomical dead space

A

volume of gas occupied by the conducting airways and this gas isnt available for exchange

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

what is surfactant

A

detergent like fluid secreted by type II pnuemocytes

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

what is the role of surfactant (4)

A

reduces surface tension on the alveolar surface membrane
increases lung compliance
reduces lungs tendency to recoil
makes the work of breathing easier

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

how does alveoli reduce surface tension

A

reduces the attraction between the water molecules lining the alveoli
these create inwardly directed pressure
surfactant reduces the inwardly directed pressure which reduces the tendency of the alveoli to collapse

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

where is surfactant most effective

A

in smaller alveoli

the surfactant molecules come together and are more concentrated

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

when does surfactant production begin

A

~25wks gestation and is complete ~36wkss

stimulated by thyroid hormones and cortisol

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

what is the relationship between premature babies and surfactant

A

premature babies suffer IRDS (infant respiratory distress syndrome)and are often given synthetic surfactant to help them breathe and survive

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

law of laplace

A 
P = 2T/r 
pressure = 2 x surface tension/radius
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is an obstructive lung disease

A

obstruction of air flow, especially on expiration

increased airway resistance

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

what is a restrictive lung disease

A

restriction of lung expansion

loss of lung compliance (lung stiffness, incomplete expansion)

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

give 2 examples of obstructive lung diseases

A

asthma

COPD

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

give 5 examples of restrictive lung diseases

A 
fibrosis 
IRDS
oedema
pneumothorax
traumatic injury
24
Q

why is asthma an obstructive lung disease

A

over-reaction of the bronchiole smooth muscle which restricts air movement

25
Q

why is COPD an obstructive lung disease

A
  • chronic bronchitis (inflammation of the bronchi)

- emphysema (destruction of alveoli, loss of elasticity)

26
Q

why is fibrosis a restrictive lung disease

A

formation of XS fibrous connective tissue
idiopathic or asbestosis
restricts expansion of the lungs

27
Q

why is oedema a restrictive lung disease

A

fluid build up around the alveoli reduces their ability to expand

28
Q

why is pneumothorax a restrictive lung disease

A

lung can’t expand and has collapsed

no longer associated with the chest wall

29
Q

how can traumatic injuries restrict lung expansion

A

pain

30
Q

what is a common technique used to measure lung function

A

spirometry

31
Q

what are the 2 types of measurements in spirometry

A

static - volume exhaled

dynamic - time taken to exhale a certain volume

32
Q

what alters normal spirometry values

A

height, weight, age

33
Q

what values can spirometry measure

A

things you can voluntarily do yourself

TV, IRV, ERV, IC, VC

34
Q

what happens to FEV1/FVC in obstructive lung disease

A

reduced e.g. 45%
rate at which air is expelled is much slower
FVC is reduced
FRC may be increased
major effect is on airways so FEV is reduced to a greater extent that FVC
ratio is significantly reduced

35
Q

what happens to FEV1/FVC in restrictive lung disease

A

increases e.g. 90%
absolute rate of airflow is reduced
total volume is reduced due to limitations on lung expansion
ratio remains constant or can increase as a large proportion of volume can be exhaled in the first second

36
Q

limitations of using FEV1/FVC

A

obstructive: both FEV and FVC fall but FEV more so, ratio is reduced
restrictive: both FEV and FVC fall so ratio remains the same despite severe compromise of function
normal ratio isnt always indicative of health

37
Q

FEF25-75

A

forced expiratory flow
average expired flow over the middle of an FVC
correlates w/ FEV1 but changes are generally more striking
normal range is greater

38
Q

what is pulmonary ventilation

A

total air movement in/out of the lungs
relatively insignificant in functional terms
TV x breaths/min
L/min

39
Q

what is alveolar ventilation

A 
FRESH AIR getting to the alveoli and therefore available for gas exchange 
functionally more significant 
(tidal dead space)/breaths/min
L/min
declines with height from base to apex
40
Q

how efficient is normal breathing

A

70%
30% gets stuck in the dead space
dead space has a huge impact on alveolar ventilation

41
Q

what is the most important determinism of alveolar ventulation

A

depth of breathing due to the impact of dead space

42
Q

hypoventilation

A

reduced alveolar ventilation

ml/min

43
Q

hyperventilation

A

increased alveolar ventilation
ml/min
just because someone is breathing quickly doesn’t mean they are hyperventilating

44
Q

how does the pressure volume curve vary across the lungs

A

varies between the apex and the base
at the base the given volume change is greater for a greater change in pressure
a small change in intrapleural pressure brings about a larger change in volume at the base compared with the apex

45
Q

how does compliance change across the lungs

A

declines with height from base to apex due to alveoli at the apex being more inflated at FRC
at the base the alveoli are more compressed between the weight of the lung above and the diaphragm below and hence are more compliant on inspiration

46
Q

Dalton’s law

A

total pressure of a gas mixture is the sum of the pressure in the individual gases

47
Q

define partial pressure

A

the pressure of a gas in a mixture of gases is equivalent to the % of that gas in the mixture multiplied by the pressure of the whole gaseous mixture
partial pressure increases with increasing [gas] in the mixture

48
Q

what are the normal partial pressures in the alveoli

A

100mmHg for oxygen
40mmHg for carbon dioxide
these are lower than in the atmosphere as the gas mixture is diluted down (dead space, residual volume and water vapour)
under normal conditions, these resting values remain fairly constant

49
Q

what can alter alveolar PO2 and PCO2

A

hyper and hypoventilation

50
Q

what changes occur during hyperventilation

A

PO2 rises - 120mmHg
PCO2 falls - 20mmHg
it is difficult to hyperventilate for a long period of time as we rely on carbon dioxide to drive the breathing cycle

51
Q

what changes occur during hypoventilation

A

PO2 falls - 30mmHg
PCO2 rises - 100mmHg
commonly seen in pathology

52
Q

define compliance

A

change in volume relative to change in pressure
represents the stretchability of the lungs (how easy it is to get air in)
changes in disease state/age

53
Q

define high compliance

A

large increase in lung volume for a small decrease in pressure
healthy lungs
in some conditions lungs can be highly compliant but lose their elasticity

54
Q

define low compliance

A

small increase in lung volume for a large decrease in intrapleural pressure
not good, common in conditions like fibrosis

55
Q

work of respiration

A

normally effort of inspiration is recovered due to elastic recoil during expiration (expiration is passive)
emphysema - loss of elastic tissue means expiration requires effort
fibrosis - inert fibrous tissue means effort of inspiration increases

respiratory system year 1 (25 decks)

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