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OLD "MBS 603" > Exam 3 -- Lecture 1 > Flashcards

Exam 3 -- Lecture 1 Flashcards

1
Q

What is compliance?

A

distensibility of the lung and chest wall

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2
Q

What does lung compliance depend on?

A

amount of elastic tissue

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3
Q

When you breath in, the thoracic cavity becomes larger and the pressure in the thorax pressure RISES/FALLS?

A

pressure falls; allowing lungs to expand and fill

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4
Q

When alveoli are filled to their limit, are they MORE/LESS compliant?

A

less compliant; stiffer

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5
Q

When you breath out, the thoracic cavity becomes smaller and the pressure in the thorax pressure RISES/FALLS?

A

pressure increases; forcing air out of lungs

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6
Q

What is the relationship of compliance with volume and pressure?

A

compliance is proportional to volume
compliance is inversely proportional to pressure

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7
Q

What is hysteresis?

A

pressure and volume are different for inspiration vs expiration

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8
Q

Why does the pressure volume curve look different for inspiration vs expiration?

A

different surface tensions at air-liquid interface of lungs
* air-liquid interface is special

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9
Q

Its difficult for alveoli to expand because there is a strong molecular force holding liquid in them together, what solves this problem?

A

surfactant

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10
Q

What cells make surfactant?

A

type II alveolar cells

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11
Q

What is surfactant made of ?

A

phospholipids

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12
Q

How does surfactant work?

A

breaks the surface tension allowing lungs to expand/inflate rapidly

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13
Q

Exhaling is a passive process so as you exhale lung surface area decreases faster than surfactant can be removed so the density of surfactant in epithelial fluid __________ and the curve is fairly flat. However as lung volume decreases, surfactant is removed and surface tension begins to ___________ again.

A

increases

increase

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14
Q

Why does the saline inflation of a lung has more compliance?

A

doesn’t have to get past air-fluid interface to break surface tension

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15
Q

What is the law of LaPlace?

A

attractive forces between molecules of liquid causes small alveoli to have very high surface tension that is hard to overcome

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16
Q

What is the relationship between pressure and radius?

A

inversely proportional
- larger radius alveoli = lower pressure (easier to keep open)

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17
Q

SMALL/LARGE alveoli make it harder to breathe

A

small

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18
Q

Smaller alveoli make it harder to breath but they are required for…

A

gas exchange (increased surface area)

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19
Q

The smaller the alveoli the LARGER/SMALLER the pressure

A

larger

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20
Q

_____ is the substance that keeps small alveoli open and available for gas exchange

A

surfactant

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21
Q

Without surfactant atelectasis would happen, what does that mean?

A

small alveoli would collapse

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22
Q

Does surfactant increase or decrease lung compliance?

A

increase (reduces work required)

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23
Q

What secretes surfactant lipids in type II alveolar cells?

A

lamellar bodies

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24
Q

If lungs were deficient in surfactant, would the opening pressure be higher or lower?

A

higher

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25
If lungs were deficient in surfactant, would it be easier or harder to inflate?
harder
26
If lungs were deficient in surfactant, would the deflation stability be better or worse?
worse
27
If lungs were deficient in surfactant, would the lung volume increase or decrease?
decrease
28
If you have increased compliance, will the line on a pressure volume curve move left or right?
left easily breathe in & harder to breathe out (increased volume with lower pressure)
29
If you have decreased compliance, will the line on a pressure volume curve move left or right?
right harder to breathe in & easier to breathe out (decreased volume with higher pressure)
30
What is a disorder that has increased compliance?
emphysema/COPD
31
What is a disorder that has decreased compliance?
fibrosis
32
In emphysema, is it harder to breath in or out?
harder to breathe out
33
In fibrosis is it easier to breath in or out?
harder to breathe in
34
Why is there an increase in compliance in emphysema/COPD?
loss of elastic fibers causes difficulty in contracting lungs to breathe out but they fill easily
35
Why is there an decrease in compliance in fibrosis?
build up of scar tissue causes difficulty pulling air in to expand lungs but they exhale easily
36
What is the condition NRDS?
lack of surfactant common in premature babies
37
Is the pressure normally in the pleural space positive or negative and why?
negative parietal pleura are attached to chest wall and are being pulled outwards HELPS HOLD LUNGS OPEN
38
If there is a puncture in the pleura the lungs ________ and the chest wall ________
collapse springs out
39
What are the 3 types of pneumothoraxes?
closed open tension
40
What is a closed pneumothorax?
damage to lungs causing air to leave lungs and into the pleural space
41
In a closed pneumothorax, the pleural space pressure is <, >, = atmospheric pressure?
pleural pressure < atm
42
What is an open pneumothorax?
damage to chest wall causing air to rush from outside into pleural space cavity
43
In an open pneumothorax, the pleural space pressure is <, >, = atmospheric pressure?
pleural pressure = atm
44
What is a tension pneumothorax?
damage to chest wall but flat covers hole resulting in air building up in pleura space because it cannot leave air comes in pleural space but cannot come out
45
In a tension pneumothorax, the pleural space pressure is <, >, = atmospheric pressure?
pleural pressure > atm
46
What is so life threatening about a tension pneumothorax?
pressure of chest can push on heart lowering cardiac output and venous return resulting in shock
47
What is the normal value for PA O2?
(alveolar) 104 mmHg
48
What is the normal value for Pa O2 in systemic arterial blood?
(arterial) 100 mmHg
49
What is the normal value for PA CO2?
(alveolar) 40 mmHg
50
What is the normal value for Pa CO2 in systemic arterial blood?
(arterial) 40 mmHg
51
What is the normal value for Pa CO2 in mixed venous blood?
(arterial) 46 mmHg
52
What is the normal value for Pa O2 in mixed venous blood?
(arterial) 40 mmHg
53
What 3 reasons are the PA O2 is lower than atmospheric air?
1. water vapor reduces amount of O2 2. some old air left in alveolar 3. Co2 being taken up into alveolar dilutes O2 levels
54
Pulmonary circulation is the output of the _______ ventricle
right
55
Is pulmonary circulation a high or low pressure system?
low pressure
56
How is pulmonary flow regulated?
change in resistance in pulmonary arterioles
57
What is the most important regulator of pulmonary flow?
PA O2 (alveolar pressure of O2)
58
If PA O2 falls, resistance INCREASED/DECREASES and blood flow RISES/FALLS.
resistance increases flow falls * doesn't seem right but its because blood flow diverts flow hypoxic alveolar to ones that work
59
When PA O2 drops why does the resistance there increase and blood flow decreases?
want to divert blood away from hypoxic alveoli to ones that work
60
Gas exchange relies on a __________
gradient
61
Why is distribution of blood flow uneven in the lungs?
gravity
62
Where is blood flow the lowest in the lungs?
zone 1 (apex)
63
Where is blood flow the highest in the lungs?
zone 3
64
In zone 1 of the lungs, PA ___ Pa ___Pv
PA > Pa > Pv
65
In zone 2 of the lungs, Pa ___ PA ___Pv
Pa > PA > Pv
66
In zone 3 of the lungs, Pa ___ Pv ___PA
Pa > Pv > PA
67
Why is ventilation in zone 1 of lungs lowest?
alveoli get filled first so they are largest = less compliant = decreased blood flow (alveoli pushing on vessel) * see slide 27
68
Why is ventilation in zone 3 of lungs highest?
alveoli are filled last so they are small = more compliant = increased blood flow (alveoli aren't pushing on vessel) * see side 27
69
Why is there a difference in the extent of ventilation in the lungs?
mixture of compliance, weight on lungs, and gravity
70
What alveoli experience greater change in volume and are better ventilated?
zone 3
71
What alveoli have more of a negative intrapleural pressure?
zone 1 expand the most
72
What part of the lungs in the least compliant?
apex (zone 1)
73
Blood flow and ventilation are the highest where in the lungs?
bottom
74
V/Q (ventilation/perfusion) ratio is highest at the top or bottom of the lungs?
top
75
Why is the V/Q ratio highest at the top of the lungs?
more ventilation but less perfusion at top large V / small Q
76
What is the normal V/Q ratio?
0.8
77
What 4 components control breathing?
1. brainstem 2. chemoreceptors 3. mechanoreceptors 4. respiratory muscles
78
What 2 structures in the brain stem control breathing?
medulla Pons
79
The dorsal side of medulla controls inspiration or expiration?
inspiration
80
The ventral side of medulla controls inspiration or expiration?
expiration
81
The dorsal respiratory group controls what?
rhythm of inspiration (send signals to diaphram to contract)
82
The dorsal respiratory group receives input from what?
pre-Botzinger complex
83
Where does the dorsal respiratory group send its message?
diaphragm (to increase contractions)
84
The ____________ respiratory group is not very active during quiet breathing why?
ventral expiration is a passive process
85
When does the ventral respiratory system become active?
exercise
86
The ventral respiratory system plays a role in the ______ reflex via the pre-Botzinger complex
sigh
87
What are the 2 pontine (Pon) centers?
apneustic center pneumotaxic center
88
What is the apneustic center?
(1 of the pontine centers) "stimulatory" causes prolonged inspirations and short expirations
89
What is the pneumotaxic center?
(1 of the pontine centers) "inhibitory" shuts off DRG thereby controlling volume of inspiration
90
Do central chemoreceptors communicate with inspiration or expiration centers?
inspiration centers
91
What gas primarily controls the medulla chemoreceptors?
CO2
92
Central chemoreceptors are most sensitive to changes in _____
pH
93
What enzyme catalyzes the reaction of CO2 + H2O ---> H2CO3 ---> H+ + HCO3-?
carbonic anhydrase
94
What gas is permeable across the BBB and is important for central chemoreceptors?
CO2
95
Can the CO2 + H2O ---> H2CO3 ---> H+ + HCO3- reaction occur in the CNS?
yes; this is how central chemo receptors sense changes in pH
96
Peripheral chemoreceptors are most senstitive to decreases in arterial _______
Pa O2
97
As blood CO2 increases, pH of CNS increases/decrease which is sensed by central chemoreceptors?
decreases
98
When blood CO2 increases, pH of CNS decreases which is sensed by central chemoreceptors which sends a message to DRG to increase/decrease breathing.
increase breathing
99
Where are peripheral chemoreceptors located?
carotid bodies and aortic arch
100
What are peripheral chemoreceptors most sensitive to changes in?
O2
101
Carotid body (peripheral chemo)receptors responds to Pa O2 < ______ mmHg
60
102
What receptor receives more blood than any other organ?
peripheral chemoreceptors
103
Activation of peripheral chemoreceptors increases/decreases the rate of breathing?
increases
104
What activates peripheral chemoreceptors?
drop in O2
105
Decreases in pH are mediated only by peripheral receptors in __________
carotid bodies
106
Sensory information received at peripheral chemoreceptors is relayed to __________
DRG
107
What are mechanoreceptors?
receptors that sense stretch in muscles (of lungs or limbs)
108
What is the Herin-Breur reflex?
mechanoreceptors in lungs sense stretch and initiate creased breathing rate by increasing expiration
109
Mechanoreceptors in limb muscles and joints sense movement and instruct __________ center to increase breathing rate
inspiratory center
110
Mechanoreceptors in the limbs are part of the ___________ response to exercise (feed-forward)
anticipatory
111
What do irritant receptors do?
in between epithelial cells in airways that cause constriction of bronchial muscles to increase breathing rate
112
What do J receptors do?
in alveolar walls that sense growing of capillaries and will increase interstitial fluid volume = decreased breathing rate
113
What zone is pressure highest in the lungs?
zone 1 (apex) alveolar pressure is highest, and pulmonary blood flow is limited
114
What central control center controls holding breath?
pneumotaxic
115
Where are the central chemoreceptos located?
under medualla
116
If you increase dead volume is it harder or easier to breath and why?
harder increases resistance
117
If an airway has a smaller radius, does the resistance increase or decrease?
increased resistance

OLD "MBS 603" (22 decks)

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