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Physiology Block 7 > Mechanics Of Breathing And Gas Eschange > Flashcards

Mechanics Of Breathing And Gas Eschange Flashcards

(79 cards)

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1
Q

What is respiration due to

A

Pressure change in alveoli with respect to atmospheric pressure

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2
Q

Volume and pressure are inversely related

A

Boyles law

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3
Q

What happens when inspiration muscles contrast

A

Increase chest volume

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4
Q

When the chest volume in crease (contraction of inspiration muscles) what happens

A
  • lungs expand due to pleural attachment
  • lowers alveolar pressure
  • air flows in
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5
Q

What does relaxation of the inspiration muscles do

A

Decreases chest volume

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6
Q

What happens there the chest volume decreases (due to relaxation of inspiratory muscles)

A
  • lungs recoil to original size
  • increases alveolar pressure
  • air is expelled
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7
Q

When is alveolar pressure increased

A

After expiration

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8
Q

What always has a negative pressure and is always lower than alveolar pressure

A

Intrapleural pressure

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9
Q

Elasticity of respiratory system

A

Very elastic

  • each piece wants to be in a nonstretched state
  • chest wall wants to expand further than allowed
  • lungs want to collapse
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10
Q

What allows for open links and air movement?

A

That fact that the chest wall wants to expand further than it is allowed and that the lungs want to collapse

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11
Q

How do the interplay of the lungs and chest wall allow for open lungs and air movements

A

Generation of pressure differences compared to outside environment

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12
Q

What is the difference in pressure from the outside environment measured by

A

Intrapleural pressure

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13
Q

What is the pressure holding the lungs open due to pleural attachments

A

Intrapleural pressure

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14
Q

Change in volume per change in pressure

A

Compliance

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15
Q

What gets altered in diseased states

A

Compliance

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16
Q

How is compliance related to elastance

A

Inversely

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17
Q

What is the equilibrium point of compliance?

A

Wher ethe forces are equal and opposite

  • chest wall expansion balanced by lung collapsing
  • equal to FRC
  • will return to this point if energy is removed
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18
Q

If all energy is removed from the system, what point will the system return to

A

FRC

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19
Q

Energy required to maintain FRC

A

None

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20
Q

If the lungs were gone at FRC

A

Chest would expand

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21
Q

If the chest wall was gone at FRC

A

Lungs would collapse

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22
Q

What does emphysema do to FRC

A

Increases it

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23
Q

What is emphysema

A

Loss of elastic fibers

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24
Q

What does emphysema do to compliance

A

Increases, harder to get air out of the lungs

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25
What does fibrosis do to FRC
Decrease it
26
What is fibrosis
Lungs lose compliance, cant stretch enough when inhaling
27
Collapsing force in fibrosis
Greater, harder to get air in
28
Normal exhalation is a process that required no energy. This is due to
Lungs collapsing pressure
29
Surface tension
Alveoli are lined with a thin film of water, water attracts other water molecules and makes the alveoli want to collapse
30
What helps counter surface tension in the alveoli?
Surfactant
31
Where is surfactant made
Type II epithelial cells
32
Surfactant
Protein and lipid mixture Keeps lungs open Makes inspiration easier
33
What makes inspiration easier
Surfactant
34
Surfactant in premature babies
It is the last thing to develop in lungs | -can cause respiratory distress of the newborn
35
Reason for changing compliance during breathing
Surfactant
36
What allows expiration to occur more rapidly at low volumes
Surface tensions
37
What kind of arrangement in airway resistance
Similar to blood flow | Parallel and series
38
_______bronchioles reduces air flow
Constricting
39
Where is there the fastes air flow
In large conducting areas such as the trachea
40
Where is the air flow the slowerst
Alveoli, allows air and blood enough time to meet
41
Where is there most control over airway resistance
Medium sized bronchioles
42
What constricts the bronchioles
PNS | Increases resistance of airways
43
What dilates bronchioles
SNS and epinephrine | Decreases airway resistance
44
Where does the bretithng cyle being
FRC
45
When the inspiratory muscles contract and the volume of the chest increases, what happens to pressure?
Falls below atmospheric pressure, which allows air to enter the lungs
46
Relaxation of the inspiratory muscles causese the chest to return to FRC and does what to pressure
Increases above atmospheric, air exits the lungs
47
Forcefully contract the expiration muscles, further reduce the chest volume and expel more air. Large increase in airway and alveolar pressure
Forced exhalation
48
What pressure is responsible for keeping the lungs open
Intrapleural
49
Between alveolar and atmospheric pressure, which is lower during inspiration
Alveolar
50
Between atmospheric and alveolar, which pressure is lower during exhalation
Atmopsheric
51
Modification of inhaled air
- heavily modified - humidified by sinuses - increases water vapor content - reduces O2 content - mixes with dead space ventilation from last exhalation to increase CO2
52
What does the inhaled air increase with CO2 content
Because it mixed with dead space centralization from last exhalation
53
What does the water content increase in inhaled air
Because the air is humidified by the sinuses
54
How is exhaled air modified
Mixes with inhalant air so it reduces in CO2 composition
55
What would happen to PAO2 if you were at altitude where the partial pressure of oxygen is reduced
Decrease. Less O2 outside, less that will get inside
56
Main function of lungs
Allow for gas exchange
57
How does transport for gas exchange occur
Simple diffusion in alveolus
58
What must happen to gas before it can be transported in blood
Dissolved
59
Gas dissolving in blood is dependent upon
Partial pressure
60
How are the partial pressure and the cxn gradient related
Directly, the higher the partial pressure, the higher the cxn gradient
61
Amount of single gas in a mixture
Partial pressure
62
How much O2 is in the air
About 20%. 160mmHg
63
Only gas in the _______ can be exchanged
Alveoli | Dead space volume is wasted ventilation
64
Air is brought to alveolus with
Blood supply
65
Ventilated alveoli with no blood supply
Wasted ventilation, you want to try to reduce this as much as possible
66
When O2 diffuses into blood what does it do
Saturates hemoglobin
67
What CO2 diffuses out of blood, where does it go
Alveolar air
68
Gas particles can me ______ limited or ______ limited
Diffusion | Perfusion
69
CO2 is _______ limited
ALWAYS perfusion | -much more permeable than O2 but low gradient
70
O2 is ______ limited
Usually perfusion | Not as permeable as CO2, but high cxn gradient
71
How can O2 become diffusion limited
In heavy exercise or lung fibrosis
72
CO is ________ limited
ALWAYS diffusion limited | -this is why CO poisoning is bad, once it gets in, it cant get out
73
Can measure the effective exchange by measuring what
A-a gradient - difference between arteriol O2 cxn and alveolar O2 cxn - PA02-PaO2
74
What is the A-a gradient usually
10mmHg | Low
75
What does a high A-a gradient tell you
Something is wrong with oxygen exchange - fibrosis - physiological shunt - exercise
76
What increases the distance between air and blood
Fibrotic diseases - increases distance between air blood, therefore reducing diffusion - takes longer to equilibrate
77
What does extreme exercise do to A-a gradient
Increases blood flow, reduces time blood spends in the caps
78
What do physiological shunts (right to left shunt) do to A-a gradient
-allows deox blood to enter arteriolar circulation
79
What would happen to a persons A-a gradient if they were at a high altitude where PIO2 was reduced
No change | O2 saturation would change though

Physiology Block 7 (10 decks)

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