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1

What instruments do we use to assess lung function?

-Stethoscopes
-Spirometer
-Peak flow meter

2

What are we listening for when using a stethoscope?

to listen for
-breath sounds
presence of mucus/fluid
-absence of breath sounds: collapsing lung?

3

What is a peak flow meter used to measure? And in who?

-measure the speed at which you can exhale
-used by chronic asthmatics on a regular basis, keep diaries of results
-need to have a certain amount of skill to use this
-very specific tool

4

How does a Spirometer work?

-nose clip worn
-breathe in and out of the mouth piece
-water in a container with a floating drum which moves up and down and feeds info into the computer

5

tidal volume

normal amount of air moved in or out in one quiet breath

6

vital capacity

amount of air that can be expelled from the lungs after forceful inhalation

7

inspiratory reserve volume

amount of air that can be inhaled after tidal inhalation

8

total lung capacity

the amount of air that can be held in the lungs after mac

9

residual volume

the amount of air that remains in the lungs during deep exhalation

10

total lung capacity women

4.2L

11

total lung capacity men

6L

12

residual volume men

1.2L

13

residual volume women

1.1L

14

expiratory reserve volume men

1.0L

15

expiratory reserve volume women

0.7L

16

inspiratory reserve volume men

3.3l

17

inspiratory reserve volume women

1.9L

18

Tidal volume for men

500ml

19

Tidal volume for women

500ml

20

what will happen if you breathe out all the air in your lungs

they will collapse

21

expiratory reserve volume

the amount of air that can be forcibly exhaled after normal tidal exhalation

22

total capacity=

IRV + tidal volume + ERV + residual volume

23

Functional residual capacity

-volume of air left in the lungs after normal exhalation
ERV+RV
-cannot be measured by spirometer (because RV can't)
-helps to stabilise the composition of alveolar air

24

inspiratory reserve volume

the amount of air that can be forcibly inhaled after normal tidal inhaliation

25

Vital capacity

amount of air that can be expired after maximum inspiratory effort
VC=IRV+TV+ERV

26

Vital capacity men

4.8L

27

Functional residual capacity

volume of air remaining in the lungs after tidal expiration
FRV= ERV+RV

28

vital capacity women

3.4L

29

Inspiratory capacity

amount of air that can be inspired after TIAL exhalation
IC = IRV +TV

30

Bigger volumes for males because

higher muscle mass and bigger thoracic cavity due to general size

31

respiratory system adapts to changing oxygen demands by changing the

number of breaths per minute (resp rate)
volume of air moved per breath (tidal volume)

32

resp volume x tidal volume =

pulmonary ventilation rate/respiratory minute volume

33

average resp rate =

12

34

pulmonary ventilation rate at rest is

6L per min

35

how much air never reaches alveoli per breath

150ml

36

name the parts of the respiratory system where air is present but no gas exchange takes place

anatomical dead space

37

alveolar ventilation

amount of air reaching alveoli per minute

resp rate x (TV - air in anatomical dead space)
12 x (500-150) =4.2L per minute

38

Smaller lung volumes in:

females
shorter people
non athletes
people at low altitude
smokers

39

higher lung volumes in:

males
tall people
athletes
non smokers
people at high altitude (coz there is less oxygen)

40

forces to overcome while breathing

Pulmonary compliance - ease with which lungs can be expanded. effected by:
-elasticity of lung issue
-surfactant
-mobility of chest wall

-Airway resistance

41

elastic recoil

inhibits inhalation
aids exhalation (passive process)
we need to overcome elastic recoil on inhaling

42

forces to overcome while inhaling

- elastic recoil
-surface tension of alveoli
-airway resistance

43

the intra pleural pressure is a smooth straight line in healthy lung. true or false?

false. its a bit wibbly coz we have to overcome certain things when inhaling

44

measuring elasticity of the lung tissue

-a measure of elastic recoil
-done by measuring the compliance of the lung - volume change of the lung resulting from a given change in pressure

45

compliance

volume change of the lung resulting from a given change in pressure c=change in

cV/c P L/cmH2O

46

How does mobility of the cage effect breathing?

problems with mobility of the cage will increase resistance in breathing

47

What is surface tension?

Forces between molecules in a liquid causing them to stick together

48

every time you breathe in your alveoli

stretch
-the air fluid interface surface of the fluid is under tension like a thin membrane being stretched

49

Laplaces law

P = 2T/r
pressure
surface tension
radius of an alveolus
at equilibrium, the tendency of increased pressure to expand the alveolus balances the tendency of the surface tension to collapse it.

50

pulmonary surfactant

increases compliance
reduces surface tension
-equalizes the pressure differences between different sized alveoli
so

51

why do we want equal pressure across all aveoli

because otherwise air will flow from the high pressure to the low pressure ones and thats just inefficient

52

how do we change the pressure in an alveoli

change the amount of surfactant. more surfactant = less tension = less pressure

53

why is there more surfactant in small alveoli

to make them easier to inflate coz they are harder
to equalize the pressure across all sizes of alveoli

54

when is surfactant produced

28-32 weeks of gestation

55

what is dangerous for babies born at 28-32 weeks

their lack of surfactant =
-reduced compliance
-alveolar collapse on exhalation
-difficult to inflate lungs
-50% die without rapid treatment
-treatment is steroids to mature lungs as quickly as possible

56

Air resistance is the
and is mainly determined by

main 'non-elastic' resistance to airflow
radius

57

where is the highest level of air resistance in the lungs?

bronchi.
although they are wider than the bronchioles etc there are more of the smaller passages

58

airway resistance reduces as

lung volume increases and the bronchi dilate

59

when do the bronchi dilate

-as the lung expands reducing resistance
-in response to the sympathetic nerves and adrenaline

60

when do the bronchi constrict

-parasympathetic causes smooth muscle to contract and bronchoconstriction
-in response to stimuli causing reflex bronchoconstriction
-smoke
-dust
-irritants
-allergens (histamine)

61

another way of measuring respiration (expiration)

get someone to breathe out as fast and hard as you can
FVC (forced vital capacity) and FEV1 Forced expiratory volume in 1st second.
majority of air should be breathed out in first second
Find the FEV1 as a percentage of the FVC - should be around 80%
used to assess changes in resistance to airflow for e.g. asthma patients

62

how do you measure changes in resistance to airflow

with FVC and FEV1