Lecture 3: Airway Resistance & Pulmonary Compliance Flashcards

1
Q

airway resistance is normally very ___

A

small

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2
Q

changes in airways resistance are brought about by changes in ___ of the airways by ____ of smooth muscles of the airways

A

radius; contraction

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3
Q

airway radius may change due to ___, ___ or ___ factors

A

physical, neural, chemical

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4
Q

resistance is the opposition to ____

A

motion

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5
Q

the flow of air into the lungs is ___ proportional to resistance for laminar flow

A

inversely

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6
Q

in astma, airway smooth muscle constricts and causes __- and ____

A

higher airway resistance and more work to breathe

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7
Q

airway resistance is primarily determined by the ___ of the airways

A

radius

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8
Q

air flow is ___ proportional to pressure difference between atmosphere and alveoli

A

directly

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9
Q

what is the major site of airway resistance in the airways?

A

large. bronchi

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10
Q

in the conducting zone, airflow velocity ___- substantially as the effective cross-sectional area increase

A

decrease

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11
Q

in the respiratory zone, airway generations exist in ___ rather than in series

A

parallel

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12
Q

what are the 4 factors that contribute to airway resistance

A
  1. lung volume
  2. viscosity
  3. autonomic nervous sytem
  4. other agents
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13
Q

what is the effect of increasing lung volume on air resistance?

A

increases airways diameter, so decreases resistance

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14
Q

the relationship between the reciprocal of resistance (conductance) and volume is ___

A

linear

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15
Q

what is the effect of increased air viscosity on airway resistance>

A

increases pressure and resistance

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16
Q

breathing ___ viscosity air, such as a mix of O2 with __-, decreases resistance and can be used as treatment for ___

A

low; He; status asthmaticus

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17
Q

what is the effect of parasympathetic activation on airway resistance?

A

constriction of airways and more resistance

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18
Q

what is the effect of sympathetic activation on airway resistance?

A

relaxation of B2 receptors, decreases resistance

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19
Q

B2 agonists are useful in treatment of ____ (ex of drug: ___)

A

asthma; albuterol

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20
Q

histamine, Ach, TxA2, leukotrienes etc are released in response to triggers (allergies, viral infections etc) and cause what effect on airway resistance?

A

bronchoconstriction; increased resistance

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21
Q

____ is characterized by increased responsiveness of the airways to various stimuli

A

asthma

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22
Q

astma manifests as widespread ___ of the airways

A

narrowing

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23
Q

what are 4 symptoms of asthma?

A
  1. excess mucus secretion
  2. chronic inflammation
  3. chest tightening
  4. coughing / wheezing
24
Q

asthma affects ~____ people worldwide and causes ____ deaths annually

A

300 million; 250 thousand

25
Q

lung compliance refers to __

A

how easy it is for the lung to expand

26
Q

the ____ the compliance, the easier it is for the lungs to expand at any given change in Ptp

A

greater

27
Q

in ___ there is destruction of the lung tissue so lungs are unable to spring back after inspiration. In this case, the compliance is too ____

A

emphysema; great

28
Q

the ___ the compliance, there is a lesser increase in lung volume for any given increase in Ptp

A

lower

29
Q

in ____, the deposition of collagen fibres into the lungs results in thickened, scar-tissue around the alveoli, making it harder to expand the lungs. In this case, the compliance is too ___

A

fibrosis; low

30
Q

emphysema is also called ___

A

floppy lungs

31
Q

fibrosis is also called ___

A

stiff lungs

32
Q

compliance is the inverse of ____ (the ability to regain original shape after distension or compression)

A

elactance

33
Q

emphysema is classed as a ____ disease

A

obstructive

34
Q

why is emphysema classed as an obstructive disease?

A

because the conducting airways will collapse due to loss of surrounding support tissue

35
Q

pulmonary fibrosis is classed as a ____ disease

A

restrictive

36
Q

why is pulmonary fibrosis classed as a restrictive disease?

A

because there is a restriction to the normal movement of air into the lungs

37
Q

lung volume depends on what 2 things?

A
  1. transpulmonary pressure

2. compliance of lung tissue

38
Q

what are the 2 major determinants of compliance?

A
  1. stretchability of lung tissue

2. surface tension at the air-liquid interface in alveoli

39
Q

the surface tension at the air-liquid interface of the alveoli is decreased by ___

A

surfactant

40
Q

____ is deficient in respiratory distress syndrome of the newborn

A

surfactant

41
Q

lungs inflated with ___ have much higher compliance compared to air-filled lungs

A

saline

42
Q

difference between air and liquid filled lungs is due to ____

A

surface tension forces

43
Q

why does a lung full of saline have higher compliance than air-filled lung?

A

saline abolishes the surface tension forces without affecting tissue forces q

44
Q

compliance is measured on the ____ limb

A

expiration

45
Q

what would happen if there were pressure differences between alveoli?

A

air would move to low pressure system and alveolus with the larger pressure would collapse

46
Q

in smaller alveoli, molecules of surfactant are ___ in relation to each other, which decreases_____ more than in larger alveoli

A

closer; surface tension forces

47
Q

what is responsible for stabilizing pressure in the alveoli?

A

surfactant

48
Q

what is surfactant made of ?

A

mix of proteins and phospholipids

49
Q

what cells secrete surfactant?

A

type 2 alveolar cells

50
Q

surfactant ___ lung compliance

A

increases

51
Q

secretion of surfactant is increased by ____

A

taking a large breath that will stretch type 2 alveolar cells

52
Q

type 2 alveolar cells are not made until the ___ week pf pregnancy

A

24

53
Q

babies with RDSN have to work harder to breathe due to ___ compliance

A

decreased

54
Q

if a mother is going into premature labour (24 weeks or before), what can be given to them to increase their babies alveolar 2 activity?

A

corticosteroids

55
Q

wha can be given to a baby after birth to better their breathing?

A

exogenous surfactant