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Flashcards in ventilation and compliance Deck (27):
1

anatomical dead space

=150 ml in alveoli
volume of gas occupied by the conducting airways - this gas is not available for exchange

2

tidal volume

volume of air breathed in or out at each breath
not combined

3

ERV - expiratory reserve volume

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

4

IRV - inspiratory reserve volume

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

5

RV - residual volume

volume of gas in lungs at the end of maximal expiration

6

VC - vital capacity

TV + IRV +ERV

7

TLC - total lung capacity

VC + RV

8

IC - inspiratory capacity

TV + IRV

9

FRC - functional residual capacity

ERV + RV

10

FEV1

forced expired volume in 1 second

11

FEV1:FVC

fraction of forced vital capacity expired in 1 second

12

pulmonary ( minute) ventilation

total air movement into/out of lungs L/min

13

alveolar ventilation

fresh air getting to alveoli - available for gas exchange L/min

14

how to calculate total pulmonary ventialtion

TV ml X RR breaths/min ml/min

15

how to calculate alveolar ventialtion

work out air to alveoli = TV- dead space (150 ml)
RR X AtA ml/min

16

partial pressure

pressure of gas in a mixture of gases is equivalent to percentage of that particular gas in the entire mixture multiplied by the pressure of the whole mixture mmHg or kPa
all gas molecules exert same pressure - so partial pressure increases with increasing concentration of the gas in the mixture

17

surfactant function

detergent like fluid produced by type 2 alveolar cells
reduces surface tension, increase slung compliance, reduces tendency to recoil, makes breathing easier
more effective in small alveoli than large - surfactant molecules are closer together in small alveoli so are more concentrated
production starts 25 weeks gestation - complete by 36 weeks , stimulated by thyroid hormones and cortisol which increase during end of pregnancy
premature babies suffer IRDS

18

define compliance

change in volume relative to change in pressure - represent the stretch-ability of the lungs ( not elasticity)

19

high compliance

large increase in lung volume for small decrease in ip pressure

20

low compliance

small increase in lung volume for large decrease in ip pressure

21

effect of emphysema on work of respiration

loss of elastic tissue means expiration requires effort instead of being passive

22

effect of fibrosis on work of respiration

inert fibrous tissue means effort of inspiration increases

23

alveolar ventilation ---- with height from base to apex

declines

24

compliance with height from base to apex...

declines - as alveoli at the base are compressed between lung above and diaphragm - so are more compliant on inspiration
a small change in ip pressure brings about a larger change in volume at base compared to apex

25

obstructive lung disease

obstruction of air flow - especially on expiration
increased airway resistance
ex asthma, COPD

26

restrictive lund disease

restriction of lung expansion
loss of lung compliance - lung stiffness, incomplete expansion
ex. fibrosis, IRDS, oedema, pneumothorax

27

spirometry - static or dynamic

technique used to measure lung function
static - only volume exhaled is measure
dynamic - time taken to exhale a certain volume is measure