Respiratory Physiology Flashcards
(196 cards)
1
Q
Name the 4 functions of the lung.
A
-prime function: gas exchange. Also metabolizes some compounds, filters unwanted materials from the circulation, and acts a resevoir for blood.
2
Q
Oxygen and carbon dioxide are exchanged by what process?
A
simple diffusion, from high pressure to low pressure
3
Q
What does Fick’s law state?
A
the amount of gas that moves across a sheet of tissue is proportional to the area of the sheet but inversely proportional to its thickness.
4
Q
The conducting airways contain no _________ and therefore do not participate in gas exchange.
A
alveoli
5
Q
Any part of the airway that does not participate in gas exchange is called?
A
dead space
6
Q
What is the typical volume of normal anatomical dead space?
A
150mL
7
Q
The terminal bronchioles divide into the ________ which have occasional alveoli budding from their walls.
A
respiratory bronchioles
8
Q
Terminal bronchioles divide into respiratory bronchioles which then come to ___________ which are completely lined with alveoli.
A
alveolar ducts
9
Q
The alveolated region of the lung where gas exchange occurs is known as the _____________.
A
respiratory zone.
10
Q
The portion of the lung distal to the terminal bronchiole forms an anatomical unit called the:
A
acinus
11
Q
The _________ zone makes up most of the lung, its volume being about 2.5 to 3 liters at rest.
A
respiratory
12
Q
During inspiration the diaphragm _______ and the intercostal muscles _________ the ribs, thus increasing the cross-sectional area of the thorax.
A
descends; raise
13
Q
Because the velocity of gas falls rapidly in the region of _____________, inhaled dust frequently settles out there.
A
terminal bronchioles
14
Q
The airway is divided into 2 zones. They are:
A
conducting zone and respiratory zone.
15
Q
Volume of the anatoic deadspace is about:_______mL.
A
150
16
Q
Volume of the alveolar region is about ____ to ____ liters.
A
2.5-3
17
Q
Gas movement in the alveolar region is chiefly by: _________
A
diffusion
18
Q
The arteries, veins and bronchi run close together but toward the periphery of the lung what happens?
A
The veins move away to pass between the lobules, whereas the arteries and bronchi travel together down the center of the lobules.
19
Q
The capillaries form a dense network in the walls of the ___________.
A
alveoli
20
Q
The diameter of a capillary segment is about _________
A
7-10 micrometers, just large enough for a red blood cell.
21
Q
The extreme thinness of the blood-gas barrier means that the capillaries are easily _________.
A
damaged
22
Q
When damage occurs to the capillaries they______________
A
leak plasma and even RBCs into the alveolar space
23
Q
The pulmonary artery receives __________ of the cardiac output.
A
100%
24
Q
The resistance of the pulmonary circuit is (large/small)
A
very small
25
Each RBC spends about ____ seconds in the capillary network.
0.75 seconds. In this time it probably traverses 2-3 alveoli.
26
How is blood supplied to the conduction airways down to the terminal bronchioles.
By the bronchial circulation. This circulation is returned on the pulmonary vein to the L. atrium, thereby contributing a small amount of used, deoxygenated blood to be circulated to the body.
27
The blood/gas exchange area is (thick/thin)?
extremely thin. Only 0.2 -0.3 micrometers over much of its area.
28
The surface area of the blood/gas interface is (large/small)?
enormous. 50-100 meters squared.
29
The blood gas interface contains how many alveoli?
about 500 million
30
The blood gas interface is so thin that large changes in capillary pressure can\_\_\_\_\_\_\_\_\_\_\_.
damage the barrier.
31
Can the lung function without the bronchial circulation?
Yes. the bronchial circulation is a mere fraction of that through the pulmonary circulation. An example of someone living without this circulation is a lung tranplant recipient. The lung functions fairly well without it.
32
Because of the ________________ of the liquid lining the alveoli, relatively large forces develop that tend to __________ the lung.
surface tension; collapse.
33
The diameter of the capillaries is about:\_\_\_\_\_\_\_\_\_\_\_\_
7-10 micrometers
34
The thickness of much of the blood gas barrier is less than\_\_\_\_\_\_\_\_\_.
0.3 micrometers
35
Blood spends about ________ seconds in the capillaries/
0.75
36
Some of the cells lining the alveoli secrete\_\_\_\_\_\_\_\_\_, which dramatically lowers the surface tension of the alveolar lining.
surfactant
37
Large particles that try to enter the lungs are filtered out by:
the nose
38
Smaller particles that deposit in the conducting airways are removed by:
mucociliary escalator, a moving stairway of mucus that continually sweeps debris up to the epiglottis where it is swallowed.
39
The mucus of the mucociliary escalator is secreted by?
mucous glands and goblet cells in the bronchial walls
40
The mucociliary escalator moves rhythmically under normal conditions but are paralyzed by:
inhaled toxins (smokers)
41
How do the alveoli get rid of particles that reach them?
alveoli have no cilia so the particles are engulfed by large wandering cells called macrophages. The foreign material is then removed from the lungs by lymphatics or in the blood flow.
42
What is the advantage of having a thin blood gas barrier with a large surface area?
ideal for gas exchange by passive diffusion
43
The conducting airways extend to the terminal bronchioles, with a total volume of about \_\_\_\_\_\_\_mL. All the gas exchange occurs in the respiratory zone, which has a volume of about \_\_\_\_liters.
150 mL; 2.5-3 Liters
44
\_\_\_\_\_\_\_\_\_\_ flow takes inspired gas to about the terminal bronchioles; beyond this movement of gas is typically by:\_\_\_\_\_\_\_\_
Convective flow; Diffusion in the alveolar region
45
When oxygen moves through the thin side of the blood-gas barrier from the alveolar gas to the hemoglobin it traverses what layers?
Surfactant; epithelial cell; interstitium; endothelial cell; plasma; red cell membrane
46
What is the Po2 in mmHg of moist inspired gas of a climber on the summit of Mt. Everest? (barometric pressure 247mmHg)
Po2= FiO2 x (pressure - vapor pressure) Po2= 0.21 x (247 -47 mmHg) Po2= 42 mmHg.
47
In the alveolar ducts, the predominant mode of gas flow is _________ rather than \_\_\_\_\_\_\_\_.
diffusion rather than convection
48
The functions of getting gas into and out of blood are carried out by what 3 functions?
ventilation, diffusion, and blood flow.
49
The amount of air inspired and expired in regular, relaxed breathing is the \_\_\_\_\_\_\_\_\_\_.
tidal volume
50
A maximal inspiration followed by a maximal expiration is the:\_\_\_\_\_\_\_ .
Vital Capacity
51
Even after maximum exhalation, some gas is left in the lung (it won't deflate down to nothing). This volume is the \_\_\_\_\_\_\_\_\_\_\_\_.
Residual volume
52
Ater a normal exhalation, the gas left in the lung is the \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.
Functional Residual Capacity
53
Which three volumes cannot be measured with a simple spirometer?
Neither the functional residual capacity nor the residual volume nor the total lung capacity.
54
How can functional residual capacity and residual volume be measured if they cannot be read by spirometry?
Gas dilution technique. The patient inhales helium which is insoluble in the blood, after some breathes the helium in the lung with equalize with the amount being administered. Another way is by body plethysmograph, where the subject sits in an airtight box and pressure and volumes are measured as the patient breathes.
55
Do the body plethysmograph and the helium dilution method measure result in the same numbers?
No, body plethysmograph measures the total volume of gas in the lung, including any that is trapped behind closed airways. The helium dilution technique measures only communicating gas. or ventilated lung volume. (In a healthy patient, these numbers are virtually the same, but in someone with diseased lungs with air trapping, the numbers would be different)
56
Why is helium used in the gas dilution test?
Because of its low solubility in the blood.
57
The use of body plethysmograph depends on which gas law?
Boyles law.
58
What is the difference between total ventilation and alveolar ventilation?
total ventilation calculates the mL per breath x the RR. It gives the total amount of air leaving the lung each minute. However; because some is dead space, not all of that volume is available for gas exchange. Alveolar ventilation is more specific and accounts for the dead space.
59
What are the 4 stages of respiration?
1. Ventilation- air into lung 2. Gas exchange from alveoli to pulmonary capillaries. 3. Gas transport from pulmonary capillaries to peripheral tissue capillaries 4. peripheral gas exchange from tissue capillaries into the cells.
60
Flow in the lungs is affected by \_\_\_\_\_\_\_\_\_\_\_\_, \_\_\_\_\_\_\_\_\_\_\_\_\_, and \_\_\_\_\_\_\_\_\_\_.
frictional reistance, shape of the conduit, and the nature of the gas
61
Bulk flow in the conducting apparatus occurs in response to \_\_\_\_\_\_\_\_\_\_\_\_\_.
Pressure gradient
62
Flow, or __________ responds to a \_\_\_\_\_\_\_\_\_\_\_\_\_.
volume over time; responds to a pressure gradient.
63
The high velocity conducting airways are the ______ and \_\_\_\_\_\_\_.
trachea and bronchi
64
The low velocity respiratory zone is comprised of __________ and \_\_\_\_\_\_\_\_\_\_\_.
bronchioles and alveolar ducts.
65
As cross sectional area decreases, pressure gradient ________ and velocity of flow \_\_\_\_\_\_\_.
decreases; decreases
66
In the alveolus, O2 and CO2 move from air to blood by simple ________ in response to a _________ .
by simple diffusion in response to a pressure gradient. (Fick's law)
67
Which gas is more diffusable CO2 or O2?
CO2
68
In a healthy person, does every RBC get exposed to oxygen in the capillary?
Yes, there is just enough room for one RBC to file through in a single file nature (everyone lines up to get a cookie)
69
How much more diffusable is CO2 than O2?
at least 20x. Think of a carbonated drink, how easily CO2 escapes. Even in a pathological state, CO2 will always be more diffusable.
70
What 2 types of cells line the alveolus?
Type 1 and Type 2 pneumocytes.
71
Which type of cells secrete surfactant?
Type 2 pneumocytes.
72
The pulmonary circulation is a (low/high) resistance circuit?
Low, pressures upon entering the circuit are low at about 12mmHg and go even lower as blood travels through, down to about 8 mmHg.
73
Name 4 factors that affect pulmonary circulation.
1. the pressures around the alveolus 2. blood flow 3. The presence of vasoconstrictors or vasodilators. 4. Acid base status
74
What kinds of pressures affect the alveolus?
pressure in the alveolar vessels (on the alveolus themselves) and the extra alveolar vessel pressures from the vessels surround the alveolus.
75
Increased blood flow, or recruitment, as in the type that occurs with exercise causes a (decrease/increase) in resistance.
decreases resistance
76
Hypoxemia vasoconstricts or vasodilates the pulmonary vasculature?
vasconstricts. As oxygen supply decreases to a region of the lung, the vessels will constrict so that blood is shunted to a part of the lung that has more oxygen available for exchange.
77
Name 2 pulmonary vasodilators?
Nitric Oxide and Oxygen
78
How does acid base status affect vasodilation or constriction?
More alkaline blood will cause pulmonary vasodilation (So, Dr. N. runs the pH a little high in patients with pulmonary hypertension)
79
If you give inhaled Nitric Oxide to a patient, as treatment for pulmonary hypertension, what is the effect on systemic blood pressure?
Nil. Nitric oxide is bound to hemoglobin quickly and is inactivated within the pulmonary vasculature, so it won't travel out to the rest of the body or have any effect on systemic BP.
80
The perfect storm for efficient oxygen exchange occurs when lung volume is ________ and pulmonary resistance is \_\_\_\_\_\_\_\_\_\_\_.
Optimal volume at low resistance. As you increase volume you will actually compress the vessels and less blood will be able to get through and be available for gas exchange.
81
As the lung expands, what happens to extra alveolar vessels?
Alveoli are pulled apart, this expands extra-alveolar vessels and decreases resistance.
82
At low lung volumes, extra alveolar resistance ___________ and alveolar or capillary vessel resistance \_\_\_\_\_\_\_\_\_\_\_
Increases; decreases (not squashed)
83
At high lung volumes, extra alveolar resistance _________ and alveolar or capillary vessel resistance \_\_\_\_\_\_\_\_\_.
decreases; increases (squashed)
84
True or False, a Saline filled lung is easier to expand than an air filled lung.
True, because there is no air/fluid interface with surface tension
85
As a healthy lung expands, surface tension \_\_\_\_\_\_\_\_\_\_.
increases
86
As a healthy lung recoils back down, surface tension\_\_\_\_\_\_\_\_\_\_\_.
decreases. which prevents the alveoli from deflating completely and makes it easier to get that next breath in.
87
Name the substance that keeps surface tension down at low lung volumes.
surfactant
88
Surface tension occurs at :
air/ liquid interfaces
89
Surfactant does 2 things. They are:
maintains stability, reduces surface tension at low lung volumes.
90
What is the treatment for PPHN?
Inhaled Nitric Oxide
91
How does inhaled nitric oxide work?
It diffuses into the pulmonary vascular bed, relaxing the pulmonary arteries.
92
Name 5 non-respiratory functions of the lung.
1. Defense- filter small particles 2. Metabolize vasoactive substances (produces angiotensin converting enzyme), 3. Metabolize bronchoactive substances (such as leukatreines- which causes bronchospasms) 3. Produces Immunoglobulins, especially IgA 4. Contain mast cells which contain Heparin.
93
What do leukatrienes do in the lung?
cause bronchospasm
94
What do mast cells do in the lung?
Produce heparin
95
The key enzyme in salt and water homeostasis is?
ACE
96
What is renin?
Renin is an enzyme secreted by the kidney that converts angiotensinogen (in the liver) to angiotensin I
97
What is ACE?
ACE is an enzyme in the lungs that converts angiotensin I to angiotensin II.
98
What 2 things does angiotensin II do to increase BP?
It constricts arterioles and expands the extracellular fluid
99
As the lung expands, extra-alveolar vessels are pulled apart. This expands the extra-alveolar vessels and \_\_\_\_\_\_\_\_\_\_\_\_resistance.
decreases
100
What are some problems that might face a lung transplant recipient?
They will have a lack of ACE, a lack if IgA, a lack of mast cells (heparin) and difficulty metabolizing bronchoactive substances like leukotrines.
101
Boyle's law tells us that as ________ increases pressure decreases.
volume
102
Is inspiration is active or passive?
active
103
During inspiration the diaphragm moves down, the ribs move forward, upward and outward. This increases the lung volume. So pressure in side the lung must \_\_\_\_\_\_\_\_\_\_\_
decrease
104
When pressure in the lung decreases below atmospheric pressure a _________ is established and bulk air flow into the lung occurs.
gradient
105
Is expiration active or passive?
Passive. Due to the elastic recoil of the chest
106
As the chest wall volume decreases in exhalation, the pressure inside \_\_\_\_\_\_\_\_\_\_\_\_\_.
increases
107
Can expiration be an active process?
Yes, for example, when playing a wind instrument or in patients with asthma
108
When expiration is active, what muscles are typically used?
abdominal, and internal intercostals.
109
Bulk flow depends on 3 factors. They are:
1. The size of the pressure gradient 2. The size and resistance of the conduit 3. The nature of the gas
110
Describe the two types of flow.
**Laminar:** smooth, streamlined, fastest flow is through the midde. **Turbulent:** at branch points and asthma, or any state that creates increased resistance, the velocity of the gas slows down and increased pressure is needed to overcome it. Not smooth flow.
111
Transitional flow occurs at:
branch points. Transition flow is turbulence not caused by a disease state but rather at normal transitional points in the airway.
112
What is one manipulatable variable in turbulent air flow?
the density of the inspired gas. For example, heliox, which is low density, is used to treat airways obstructed by croup or asthma.
113
What is heliox?
Heliox is a combination of 80 parts helium and 20 parts oxgyen.
114
How does heliox work?
The low density heliox converts turbulent flow to laminar flow.
115
Name 2 factors affecting airway resistance.
Generation of the airway and lung volume.
116
Most airway resistance occurs up to the __________ generation.
7th
117
The greater the lung volume the ________ the lung resistance.
lower
118
How does bronchial smooth muscle affect airwary resistance?
If bronchial smooth muscle is contracted, airway resistance goes up.
119
If beta 2 receptors are blocked, what happens to airway resistance?
resistance goes up
120
Name two naturally occuring substances in the body that would block beta 2 receptors and cause bronchoconstriction.
acetylcholine and histamine
121
Terbutaline and albuterol have what effect on beta 2 cells?
They are beta agonists that bronchodilate. They are used to treat asthma.
122
Because of the effects of barometric pressure on the gas, the gas inhaled by deep sea divers has increased \_\_\_\_\_\_\_\_.
density
123
The increased density of the gas breathed by deep see divers could cause ________ in the airway.
resistance, turbulent flow. Therefore divers often breathe some form of heliox to overcome this.
124
Forced expiration, like pursed-lip breathing (increases/decreases) airwary resistance.
increases. They dynamic compression of the airways against the pursed lips causes an increase in airway resistance.
125
In forced exhalation, pressure is built up in the airways up to a _________ point. At which point flow goes racing out like a waterfall effect.
Choke point
126
Once you get past the choke point, what amount of the airflow is from the patients own effort?
None, once past the choke point, flow is effort indepedent.
127
The term that describes a change in volume for a given change in pressure is:\_\_\_\_\_\_\_\_\_
compliance
128
Elastic recoil of the lung occurs faster than the stretching of inhalation. Therefore the deflation curve on a volume pressure graph has a _________ slope.
steeper
129
What are the effects of aging on lung compliance?
Like an old elastic band. Expands easily but does not recoil well. (increased compliance)
130
What are the effects of asthma on lung compliance?
Breathing in is easy but it is difficult to breathe out against restricted airways. (higher compliance)
131
What is the effect of fibrosis on lung compliance?
Fibrosis in the lungs scars the interstium and makes the lung both less stretchable and less able to recoil. decreased compliance.
132
Does a lung with emphysema have increased or decreased compliance?
increased. Can breathe in easily but not out so well.
133
Does a lung with pulmonary fibrosis have increased or decreased compliance.
decreased.
134
Does a lung with alveolar edema have increased or decreased compliance?
decreased
135
Does a lung with atelectalis have increased or decreased compliance?
decreased
136
Does a hypoventilated lung (like with narcotics) have increased or decreased compliance?
decreased
137
Does increased pulmonary venous pressure cause an increase or decrease in compliance?
decrease
138
The elastic recoil of the lung tends to pull it inward but it is balanced by the ___________________ that counters that and balances it.
elastic recoil of the thoracic cage
139
What is the volume of the lung that exists at the point where the elastic recoil of the lung pulling inwards and the elastic reoil of the thoracic cage pulling outward are balanced.
Functional residual capacity
140
Name 2 good things the functional residual capacity does for us.
1. keeps the lung open 2. acts as a bank to supply O2 when needed.
141
By 'keeping the lung open', the functional residual capacity keeps _________ pressure negative.
intrapleural
142
What effect does incentive spirometry have on functional residual capacity?
It maximizes FRC, preventing lung collapse
143
Elastic recoil of the lung depends on _______ at the air-fluid interface of the alveoli.
surface tension
144
Which cells produce surfactant?
Type 2 pneumocytes
145
Name 5 effects surfactant has on the lungs.
1.It decreases surface tension at low lung volumes. 2.Increases compliance of the lung 3. Promotes stability of the alveoli 4.Keeps alveoli dry 5. Contributes to hysteresis
146
What is hysteresis?
The difference in inflation and deflation volumes at a given pressure. The difference exists because of the air- water surface tension at the beginning of inhalation and because deflation is faster with the elastic recoil of the chest.
147
Hysterisis would be less marked in a saline filled lung, why?
Because a fluid filled lung has no surfactant
148
Surfactant _______ (increases/decreases) hysteresis.
decreases
149
What are type 1 pneumocytes?
large, flattened, non-replicating cells involved in gas exchange.
150
What happens when type 1 pneumocytes are damaged?
You get DAD (diffuse alveolar disease) as seen in SARS
151
Type 2 cells can differentiate into ___________ if needed but \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.
Type 1 but type 1 cannot differentiate into type 2s.
152
Are ventilation and pefustion uniform throughout the lung?
No. They are non-uniformally distributed in the upright lung.
153
Blood flow to the lung is _________ in the apex and \_\_\_\_\_\_\_\_\_\_\_at the base because of gravitational effects.
lowest; highest
154
Ventilation is _________ at the apex and ________ at the base.
Lowest; highest
155
The V/Q ratio is ___________ at the apex and _________ at the base.
higher; lower
156
Ventilation (increases/decreases) from the base to the apex of the lung in the upright position.
decreases
157
\_\_\_\_\_\_\_\_\_ (apex/base) is aerated better at baseline because surrounding intrapleural pressure is more negative here.
Apex
158
Per unit volume ventilation is (better/worse) at the base when compared to the apex.
better
159
What is the partial pressure of O2 in the atmosphere?
Since O2 makes up 21% of our air, 21/100 x 760 mmHg = 149.73 or 150mmHg
160
What does R represent in the alveolar gas equation?
R is the respiratory quotient. It represents the amount of CO2 generated per molecule of O2 utilized.
161
What is the normal R value at basal metabolic rate?
0.8
162
What is the normal value for PaO2 in a healthy lung?
95 mmHg for a healthy person breathing room air at sea level
163
What is the alvelo- arterial gradient? What is the normal level?
The gradient that exists between the alveolar O2 and the arterial O2. PAO2- PaO2. Normal value is 5-10mmHg.
164
Why would there by any difference ( the 5-10mm Hg accepted value) between the PAO2 and the PaO2?
because of physiological shunting. Some blood will enter the left heart without being oxygenated (ex. bronchial circulation) and this is ok at low levels.
165
When would an increased Alveolar arterial gradient occur?
When there is a diffusion problem. As happens when the there is increased thickness in the wall or membrane.
166
How do you calculate minute ventilation?
tidal volume x respiratory rate
167
What are the 4 volumes of the lung?
Tidal volume, Residual Volume, Inspiratory reserve volume and expiratory reserve volume.
168
What are the 4 capacities of the lungs?
Total lung capacity, vital capacity, inspiratory capacity and functional residual capacity.
169
Which two capacities are essentially the same
FVC and VC
170
Anything that involves measuring reserve capacites or volumes (can/ cannot) be measured by basic spirometery?
cannot
171
172
How can you measure anatomic dead space?
By Fowler's method, which uses O2 to washout nitrogen.
173
Physiological dead space contributes to the amount of CO2, true or false.
False. Gas in the dead space does not participate in gas exchange and therefore does not generate CO2.
174
does PACO2 = PaCO2?
Yes, it should. CO2 is highly diffusable so arterial and alveolar CO2 will quickly reach equilibrium
175
Tidal volume includes for both alveolar ventilation and dead space. True or False
True
176
If alveolar ventilation is halved, what should happen to your PaCO2?
it is doubled
177
Oxygen transfer from alveolus to artery is very efficient and is typically only limited by \_\_\_\_\_\_\_\_\_\_\_\_\_.
Perfusion. or the number of RBCs available to pick up a molecule of O2.
178
Which would be more likely to occur at high altitude, hypoxia or hypercarbia?
hypoxia. getting CO2 out is not the issue, getting O2 in is the issue.
179
Which would be more likely to occur in interstitial lung disease, hypoxia or hypercarbia?
hypoxia. CO2 is more easily diffused so it will diffuse out a lot easier than oxygen will diffuse in.
180
Which is more likely to occur in hypoventilaton, hypoxia or hypercarbia?
Hyerpcarbia. If you are breathing less there is more CO2 sitting in the alveolus. Passing blood CO2 will only diffuse out if a gradient exists.
181
The transfer of CO is _________ limited.
diffusion
182
CO is used to measure _________ capacity, which is decreased in interstitial lung fibrosis, sarcoidosis, or asbestosis
diffusion
183
Hypoxemia: (Low O2 tension in arterial blood) could be caused by:
Low inspired O2, Hypoventilation, diffusion limitation, shunt, ventilation-perfusion mismatch.
184
What sorts of things cause hypoventilation?
Drugs (morphine, barbiturates), damage to the chest wall, weakness of the respiratory muscles, increased resistance to airflow, as in deep sea diving.
185
Does hypoventilation cause hypercarbia?
Yes, it always does.
186
If pCO2 rises, what happens to alveolar O2?
it will decrease.
187
Oxygen delivery to the tissues depends on \_\_\_\_\_\_\_\_\_\_.
perfusion
188
Diffusion limitations can be overcome by increasing O2 only if\_\_\_\_\_\_\_\_\_\_\_\_\_
the alveolus is adequately perfused
189
How does increased PO2 in the alveolus increase the PO2 in the artery?
it increases the gradient
190
What are 2 sources of physiological shunts?
bronchial and coronary circulation
191
Name 4 common causes of pathological shunts?
AV malformations, ASDs, VSDs, PDAs.
192
Does oxygen help treat a shunt?
No. it doesn't matter how much O2 you put in the alveolus, if blood isn't getting to it there will be no gas exchange.
193
What happens to oxygen once it enters the blood?
Most of it is bound to hemoglobin but some of it will bubble around as free O2 in the blood exerting a partial pressure.
194
\_\_\_\_\_\_\_\_\_\_\_ law helps us calculate how much O2 is carried in the blood in a dissolved state.
Henry's
195
Henry's law states:
The amount of gas dissolved in a liquid is proportional to the partial pressure of the gas in the liquid.
196
