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
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Intrapleural pressure is always POSITIVE / NEGATIVE with respect to atm pressure and alveolar pressure
negative
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Volume of pleural cavity
15 mL
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The inner membrane of the pleura is called...
visceral pleura
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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