PSL301: Respiratory 2 Flashcards Preview

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Flashcards in PSL301: Respiratory 2 Deck (72):
1

Tachypnea

rapid breathing

2

Tachycardia

rapid heart rate

3

Cyanosis

Person turns blue, especially under the nails

4

Trachypnea, tachycardia, grunting when expiring, and cyanosis are symptoms of...

Respiratory distress syndrome of the newborn

5

Treatment for respiratory distress syndrome of the newborn

Artificial surfactants
Respirator

6

Boyle's Law

P1V1 = P2V2

7

relationship between pressure and volume

Inversely proportional

8

How does air get into lungs?

Diaphragm contracts, increasing thoracic volume = decreasing thoracic pressure.
Atm pressure > alveolar pressure
Air flow down pressure gradient

9

How does air get out of the lungs?

Diaphragm relaxes, decreasing thoracic volume = increasing thoracic pressure.
Atm pressure < alveolar pressure
Air flow down pressure gradient

10

Diaphragm is controlled by __ nerve

phrenic nerve

11

Where is the phrenic nerve located?

spinal segments C3, C4, C5

12

Scalenes are attached to the...

first 2 ribs

13

sternocleidomastoids are attached to the...

sternum

14

Inspiratory muscles consist of...

external intercostals
sternocleidomastoids
scalenes

15

The rib cage can increase in dimension in 2 ways

1. anterior-posterior (pump handle)
2. lateral (bucket handle)

16

When are expiratory muscles used?

- voluntary expiration
- fast breathing frequency

17

Internal intercostals effect on rib cage during expiration

contract -> force rib cage inwards

18

Abdominal muscles effect on rib cage during expiration

contract -> force rib cage inward & force abdomen into thoracic cavity to decrease lung volume

19

How does the movement of diaphragm and rib cage affect the lungs when they are not attached to the thoracic wall?

Fluid in pleural cavity has enough surface tension, and act as glue

20

Intrapleural pressure

Pressure in pleural cavity

21

Intrapleural pressure is always POSITIVE / NEGATIVE with respect to atm pressure and alveolar pressure

negative

22

Volume of pleural cavity

15 mL

23

The inner membrane of the pleura is called...

visceral pleura

24

The outer membrane of the pleura is called...

Parietal pleura

25

Are expiratory muscles normally used?

No, expiration is usually a passive process

26

What creates the intrapleural pressure?

The opposing forces between the chest wanting to expand and the lungs wanting to collapse

27

___ of the chest wall tries to pull chest outwards

elastic recoil

28

____ of the lungs creates an inward pull

elastic recoil

29

Pneumothorax

Collapsed lung
Puncture in the intrapleural cavity makes it atm = no more glue

chest and lungs do whatever they want:
chest expand out
lungs collapse in

30

Treatment for penumothroax

- wet dressing to wound (air in pleural cavity can only flow outwards)
- CPR to re-inflate lungs

31

How does the alveolar pressure change during inspiration & expiration?

sin graph
min = middle of inspiration (-1 mmHg)
max = middle of expiration (+1 mmHg)

32

How does the intrapleural pressure change during inspiration & expiration?

-3 at the beginning of inspiration
-6 at the beginning of expiration

Remember that it is always negative!

33

Which takes longer, inhale or exhale?

Exhale takes about 3x longer

34

2 factors that influence breathing

1. lung compliance
2. airway resistance

35

Lung compliance

Degree the lungs will comply by changing their volume when subjected to change in intrapleural pressure

36

Lung compliance is influenced by...

1. elastin fibre
2. surface tension in alveoli

37

Airway resistance

Force that opposes the movement of air

38

Airway resistance is influenced by...

1. type of flow
2. airway diameter

39

Elastin fibres are found...

between alveolar cells

40

Elastin fibers are composed of...

single elastin molecules cross-linked with each other

41

What happens to elasticity of lungs as we get older?

decreases

42

What happens to elasticity in people with empysema?

decreases

43

Relationship between elasticity and compliance?

Inverse

44

Formula: lung compliance

CL = change in volume / change in distending pressure

45

distending pressure

pressure difference between alveoli and intrapleural cavity

46

Pulmonary fibrosis causes lung compliance to...

get worse (harder to expand)

47

Emphysema causes lung compliance to...

get better (expand easily)

48

surfactants ___ the surface tension

reduce

49

Increased surface tension will cause alveoli to...

shrink
(more pressure pushing on the bubble)

50

Law of LaPlace

P = 2T/r

51

According to LaPlace, what size alveoli experience greater pressure?

smaller ones

52

Purpose of surfactants at the aveoli

To equalize the pressures experience by the big and small bubbles

53

Why don't we want smaller alveoli collapsing into bigger ones?

Smaller ones have more SA, which is better for gas exchange

54

Respiratory distress syndrome of the newborn is due to...

Premature baby:
Type II alveolar cells don't produce enough surfactant, so less SA at alveoli -> less gas exchange

55

3 types of flow

1. laminar
2. turbulent
3. intermediate

56

What type of flow is in the respiratory system?

Intermediate:
mainly laminar, but turbulent at branch points

57

Formula for resistance

Ln/r^4

L = length of tube
n = viscosity of air
r = radius of tube

58

90% of the resistance in the airway comes from...

trachea & bronchi

59

How does the bronchioles contribute to resistance?

Not much (large x-section area)
By changing diameter (smooth muscles)

60

Histamine causes the bronchioles to...

constrict

61

CO2 / E on B2-adrenergic receptors cause bronchioles to...

dilate

62

When resistance in airway is increased, what happens to the pressure?

More negative alveolar pressure during inspiration
More positive alveolar pressure during expiration

Needed to maintain constant volume of air

63

Total pulmonary ventilation tells us...

how much air moves into and out of the lungs per minute

64

Formula: total pulmonary ventilation

minute ventilation = VT * respiration rate

65

Normal respiration rate

12 breaths/min

66

Normal minute ventilation

6000 mL/min

67

Formula: alveolar ventilation

(VT - DSV) * RR

68

How much air is usually in the dead space?

150 mL/br

69

Alveolar ventilation is...

volume of air reaching the gas exchange areas per minute

70

Difference between total ventilation and alveolar ventilation

Alveolar ventilation takes into account DSV, which does not reach the alveoli

71

Typical alveolar ventilation is...

4200 mL/min

72

How to increase the ventilation of the lungs?

Increase tidal volume AND increase breathing frequency