Physiology 2 - Respiratory mechanisms Flashcards

1
Q

2 major inspiratory muscles

A

1) diaphragm

2) external intercostal muscles

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2
Q

3 accessory muscles of inspiration

A

1) sternacleidomastoid
2) scalenus
3) pectoral

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3
Q

2 muscles of active expiration

A

1) abdominal muscles

2) internal intercostal muscles

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4
Q

tidal volume

A

volume of air entering of leaving lungs during a single breath

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5
Q

inspiratory reserve volume

A

extra volume of air that can be maximally inspired over and above the typical resting tidal volume

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6
Q

expiratory reserve volume

A

extra volume of air that can be actively expired by maximal contraction beyond normal volume of air after resting tidal volume

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7
Q

residual volume

A

minimum volume of air remaining in lungs even after maximum expiration

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8
Q

functional residual capacity

A

volume of air in lungs at end of passive expiration

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9
Q

vital capacity

A

maximum volume of air that can be moved out during a single breath following a maximal inspiration

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10
Q

total lung capacity

A

Total volume of air that the lungs can hold

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11
Q

inspiratory capacity

A

maximum volume of air that can be inspired at the end of a normal quiet expiration

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12
Q

can residual volume be measured by spirometry?

A

residual volume CANNOT be measured by this piece of apparatus

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13
Q

whats the effects on residual volume when the elastic recoil of the lungs is lost

A

residual volume increases/worsens

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14
Q

what is forced vital capacity (FVC)

A

maximum volume that can be forcibly expelled from lungs following maximum inspiration

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15
Q

what is FEV1

A

forced expiratory volume in one second

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16
Q

what is FEV1/FVC ratio

A

the proportion of forced vital capacity that can be expired in the first second

17
Q

what is the primary determinant of airway resistance?

A

radius of the conducting airway

18
Q

name 5 factors that affect airway resistance

A

1) lung volume
2) bronchial smooth muscle tone
3) type of airflow
4) gas density & viscosity
5) dynamic airway collapse

19
Q

what would you need to do to lung volume to decrease airway resistance?

A

BACKGROUD

  • bronchi are supported by lung tissue
  • increasing volume of lung tissue, decreases resistance as the diameter is increased
20
Q

what type of bronchial smooth muscle causes contraction and what causes dilation and thus which causes more & less resistance?

A

PARAsympathetic = bronchoCONSTRICTION, most resistance

Sympathetic = bronchoDILATION, increasing airway diameter, decreased resistance

21
Q

what type of airflow causes less resistance and what causes the most?

A

1) laminar flow causes less = air molecules move parallel down bronchi
2) bronchi causes more = air molecule move in a disordered fashion

22
Q

describe what effect to gas density & viscosity increases resistance?

A

increasing gas density & viscosity increases resistance

23
Q

what is dynamic airway compression?

A

the rising pleural pressure during active expiration which compresses the alveoli & airway

24
Q

explain the effect dynamic airway compression has on normal healthy people.

A
  • it causes no problems
  • increased airway resistance causes an increase in airway pressure upstream
  • helping open the airways by increasing the driving pressure between the alveolus & airway
25
Q

explain the effect of dynamic airway compression if there is an airway OBSTRUCTION.

A
  • if there is an obstruction, the driving pressure between alveolus & airway is lost
  • causing a fall in airway pressure along the airway downstream resulting in airway compression by rising pleural pressure during active expiration
26
Q

what effect does disease have on airways?

A

diseased airways are more likely to COLLAPSE

27
Q

what is pulmonary compliance

A

measure of the effort that has to go into stretching or distending the lungs/chest walls

28
Q

what 2 factors affect pulmonary compliance

A

1) elasticity

2) surface tension

29
Q

if the lungs are less compliant, what does that mean in terms of work required?

A

more work is required to produce a degree of inflation

30
Q

5 things that decrease pulmonary compliance?

A

1) pulmonary fibrosis
2) pulmonary oedema
3) collapsed lung
4) pneumonia
5) absence of surfactant

31
Q

2 factors which increase pulmonary compliance

A

1) elastic recoil of lung is lost (easier to inflate)

2) increases with age

32
Q

what disease is associated with increased compliance

A

EMPHYSEMA
- elastic tissue is lost, so patients have no problem inhaling and inflating the lugs but more effort is needed to exhale. leading to hyperinflation.

33
Q

what does work of breathing refer to?

A

amount of effort needed to expand the lungs

34
Q

what is work of breathing

A

amount of effort needed to expand the lungs

35
Q

3 factors which increase work of breathing in people with lung diseases

A

1) lung volumes
- low lung volumes, the airways marrows & therefore increase resistance

2) airway obstruction
- increase airway resistance
- increasing work of breathing

3) restrictive chest wall or lung disease (e.g. obesity)
- increase the effort required to stretch the chest wall & thus increase the work of breathing

36
Q

give 4 scenarios where work of breathing is increased

A

1) pulmonary compliance is decreased
2) airway resistance increased
3) elastic recoil decreased
4) need for increased ventilation