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282 Cards in this Set
- Front
- Back
What is the PO2 in the arteries?
|
100
|
|
What is the PCO2 in the arteries?
|
40
|
|
What is the PO2 in the veins?
|
40
|
|
What is the PCO2 in the veins?
|
46
|
|
What happens when the diaphragm contracts?
|
Inhalation; expanding the volume of the thorax
|
|
Where does gas exchange take place?
|
The alveolar ducts and alveoli
|
|
What is the alveolar wall?
|
An array of capillary segments
|
|
What cells make surfactant?
|
Alveloar type 2 cell; pneumocyte type 2
|
|
What is the total atmospheric pressure?
|
760 mmHg
|
|
How much of the total atmospheric pressure does O2 make up?
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21%
|
|
How much of the total atmospheric pressure does N2 make up?
|
79%
|
|
What is the partial pressure of 02?
|
160 mmHg
|
|
What is the partial pressure of N2?
|
600 mmHg
|
|
What is the equation of a partial pressure of a gas?
|
Pgas=Fgas * Ptot
|
|
Does the partial pressure change in the airways? Why?
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Yes; due to water vapor
|
|
What is the partial pressure of water vapor?
|
47 mmHg
|
|
What is the partial pressure of O2 and N2 in the airways?
|
713 mmHg
|
|
What is the partial pressure of O2 in the airways?
|
150 mmHg
|
|
What is the parial pressure of N2 in the airways?
|
563 mmHg
|
|
How do gases move?
|
Down a partial pressure gradient
|
|
What is the A-a difference?
|
The difference between the PAO2 and the PaO2
|
|
If the A-a dfference is large, what does this mean?
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That it is a poor exchanger
|
|
What factors determine how much gas is exchanged by the system?
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Area, thickness, solubility, concentration gradient, and degree of matching
|
|
What is the ideal exchanger?
|
When the ventilation and the perfusion are perfectly matched
|
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If the ventilation and the perfusion are perfectly matched, what is the A-a difference?
|
Minimal
|
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What happens when an airway is blocked?
|
There is no ventilation but there is perfusion
|
|
When there is no ventilation but there is perfusion, what is this called?
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Right to left lung shunt
|
|
What does the shunt result in?
|
Lowering the partial pressure of O2 in the mixed blood leaving the lung
|
|
What happens when there is an embolus?
|
There is no perfusion but there is ventiation.
|
|
When there is no perfusion but there is ventilation, what is this called?
|
Dead space; wasted ventilation
|
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What happens to the PAO2 and the PaO2 in dead space?
|
The PAO2 will be higher than normal and the PaO2 will be normal
|
|
What keeps the lungs inflated?
|
A negative pleural pressure of 7.5
|
|
What happens to the chest wall on inspiration?
|
The diaphragm is pulled up, the rib cage is pulled in, and the lung is inflated
|
|
What is the lung's elastic recoil force acting to do?
|
Collapse the lung
|
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What is the chest wall's elastic recoil force acing to do?
|
Expand the chest wall
|
|
What is the functional residual capacity (FRC)?
|
When the elastic recoil forces of the lung and chest wall are equal and opposite; equiibrium
|
|
What is happening at FRC?
|
Your mouth is open and your respiratory muscles are all relaxed
|
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What is the main contributor to lung recoil?
|
Surface tension
|
|
What is Laplace's Law?
|
P=T/R
|
|
What does surfactant do?
|
Lowers surface tension
|
|
If surfactant is not present, what happen?
|
Lung recoil forces are very high
|
|
Is surfactant more concentrated in a smaller lung or bigger lung?
|
Smaller lung
|
|
Is surfactant hydrophobic or hydrophilic?
|
Hydorphobic
|
|
What keeps the pressure the same in lungs of different sizes?
|
Surfactant
|
|
What does surfactant do to compliance?
|
Lowers compliance
|
|
Where does the recoil force come from?
|
Tissue elastic recoil forces and surface tension forces
|
|
Is inhalation an active or passive process?
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Active process
|
|
Is exhalation an active or passive process?
|
Passive process
|
|
Is forced exhalation and avtive or passive process?
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Active process
|
|
What is the pressure in the alveoli at FRC?
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Zero
|
|
What is the alveoli pressure during inspiration?
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Negative
|
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What is the alveoli pressure at the end of inspiration beginning of exhalation?
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Zero
|
|
What is the alveoli pressure during expiration?
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Positive
|
|
What is the alveoli pressure at the end of the respiratory cycle?
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Zero
|
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What is the pleural pressure at FRC?
|
Negative
|
|
What is the pleural pressure during inspiration?
|
More negative
|
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What is the pleural pressure at the end of inspiration beginning of expiration?
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More more negative
|
|
What is the plueral pressure during expiration?
|
Less negative (than during expiration)
|
|
What is the pleural pressure at the end of the respiratory cycle?
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Negative
|
|
What kind of pleural pressure does forced exhalation give?
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Positive
|
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What holds the lung expanded during normal breathing?
|
Negatvie pleural pressure
|
|
In the pressure-volume graph, what does slope measure?
|
Compliance
|
|
What is a cheap and easy way to measure lung compliance?
|
Spirometer
|
|
What does the spirometer measure in order to tell us lung compliance?
|
Relaxation pressures
|
|
What does fibrosis due to lung compliance?
|
Lowers it because it makes it harder to inflate
|
|
If surfactant is lost, what happens to lung compliance?
|
It is lowered
|
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What does emphysema do to lung compliance?
|
It raises lung compliance becuase of the loss of elastic fibers; lung is easier to inflate
|
|
What are the pleural and alveoar pressures during forced expiration?
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Both are positive
|
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What happens to the airways during forced exhalation?
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They collapse
|
|
What expels gas in a noraml passive exhalation?
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Lung elastic recoil force
|
|
What does less recoil force mean?
|
Less airflow
|
|
What kind of exhalation are emphysema patients using?
|
Forced exhalation
|
|
What happens to the side wall pressure when gases are flowing fast?
|
It decreases
|
|
What happens to airways when the flow is fast?
|
They collapse
|
|
Where is flow rate the greastest?
|
In the large airways
|
|
What promotes stability of airways or alveoli?
|
Tethering--interconnections attaching aveoli to their neighbors
|
|
What are 2 factos that can keep airways open?
|
"Pursed-lip" breathing and PEEP
|
|
What does pursed lip breathing do?
|
Keeps a higher pressure along the airway to prevent collapse
|
|
Where is pleural pressure the most negative?
|
The uppermost part of the thorax
|
|
Where is pleural pressure the least negative?
|
The lowermost part of the thorax
|
|
What is repsonsible for the distribution of ventilation?
|
Gravity
|
|
During inhalation, do alveoli at the top of the lung or at the bottom of the lung have the greatest voume change?
|
The alveoli at the bottom of the lung
|
|
Which part of the lung is the most ventilated?
|
The bottom part of the lung
|
|
What is the single most valuable pulmonaty function test you can do?
|
Spirometer
|
|
What is FEV?
|
Forced expiratory volume in 1 sec
|
|
What is FEV an estimate of?
|
Airway resistance
|
|
The larger the FEV.....
|
The lower the resistance is
|
|
The smaller the FEV.....
|
The higher the resistance is--indicative of disease
|
|
What happens to the volume-flow loop in emphysema?
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It is shifted to the left--concave curve
|
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What happens to the volume-flow loop in asthma?
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Limits flow but does not affect volume; shorter
|
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What happens to the volume-flow loop in fibrosis?
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The loop is shifted to the right; smaller volumes; no affect on flow rates
|
|
What is the residual volume?
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The amount of gas left behind after a maximal exhalation
|
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What is the tidal volume?
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The amount of gas inhaled or exhaled during normal breathing
|
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What is the FRC?
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The volume remaining in the lung after normal relaxed exhalation
|
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What happens to the volume-flow loop in fibrosis?
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The loop is shifted to the right; smaller volumes; no affect on flow rates
|
|
What the the vital capacity?
|
The volume of gas expired when you for from full inhalation to a maximum exhalation
|
|
What is the residual volume?
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The amount of gas left behind after a maximal exhalation
|
|
What is the tidal volume?
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The amount of gas inhaled or exhaled during normal breathing
|
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What is total lung capacity?
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Total amount of gas in the lungs after maximal inhalation
|
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What is the FRC?
|
The volume remaining in the lung after normal relaxed exhalation
|
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What do you measure with a standard spirometer?
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FEV
|
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What the the vital capacity?
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The volume of gas expired when you for from full inhalation to a maximum exhalation
|
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What do you measure with a helium spirometer?
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FRC
|
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What is total lung capacity?
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Total amount of gas in the lungs after maximal inhalation
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What is the main respiratory muscle?
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Diaphragm
|
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What do you measure with a standard spirometer?
|
FEV
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What do you measure with a helium spirometer?
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FRC
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What is the main respiratory muscle?
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Diaphragm
|
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How much air do we pump into alveoli every minute?
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3600 ml
|
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How much O2 is extracted per minute from the gas in the alveoli?
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250 ml
|
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How much CO2 do we put into the aveoli per minute?
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200 ml
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After gas exchange, how much O2 do the alveoli contain?
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506 ml
|
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After gas exchange, how much CO2 do the alveoli contain?
|
200 ml
|
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After gas exchange, how much N2 do the aleveoli contain?
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2844 ml
|
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What is the mole fraction of O2 after gas exchange?
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0.142
|
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What is the mole fraction of CO2 after gas exchange?
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0.056
|
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What is the mole fraction of N2 after gas exchange?
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0,801
|
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How many total ml's of gas do the alveoli contain after gas exchange?
|
3550 ml
|
|
What is the equation for tidal ventilation?
|
Vt * f = Vd * f + Va * f; f=frequency of breaths per minute
|
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What is Va?
|
Ventilation of exchanging areas
|
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What is Vd?
|
Ventilation of dead space
|
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What is the alveolar gas equation 1?
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PaCO2~VCO2/Va
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In the alveolar gas equation 1, what happens if you double the Va?
|
Halve the PaCO2
|
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In the alveolar gas equation 1, what happens to the VCO2 if you double the PaCO2?
|
Double the VCO2
|
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What happens to PaCO2 during hyperventilation?
|
The PaCO2 is halved
|
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What happens to the PaCO2 during hypoventilation?
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The PaCO2 is doubled
|
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What is the PaCO2 set by?
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The rate of ventilation and the rate of CO2 production
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What is the alveolar gas equation 2?
|
PAO2 = PiO2 - PaCO2 / R
|
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What happens to PAO2 during hyperventilation?
|
Raised PAO2
|
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What happens to PAO2 during hypoventilation?
|
Lowers PAO2
|
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What happens to PAO2 during high altitude?
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Lowers PAO2
|
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What are the two types of dead space?
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Anatomical dead space and physiological dead space
|
|
Where is anatomical dead space?
|
The large airways
|
|
Where is physiological dead space?
|
Alveoli that are venitlated but are not perfused
|
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When we measure dead space, are we measuring physiological or anatomical dead space?
|
Physiological dead space
|
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Where is O2 transported?
|
From the lungs to the tissues
|
|
Where is CO2 transported?
|
From the tissues to the lungs
|
|
In metabolizing organs, what happens to O2 and CO2?
|
O2 is consumed and CO2 is produced
|
|
What is the amount of O2 dissolved in blood a funtion of?
|
The partial pressure of the gas and the solubility of the gas in the liquid
|
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For blood in the lungs, where PO2 is 100, the amount of O2 dissolved is?
|
O.3 ml/dl
|
|
What two forms is O2 carried in?
|
Dissolved in the plasma and bound to hemoglobin
|
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Is O2 poorly or greatly soluble in water?
|
Poorly soluble in water
|
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What does hemoglobin do for O2?
|
Serves as a buffer
|
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How is O2 tranported throughout the blood?
|
Hemoglobin
|
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How is the vast majority of hemoglobin carried in the blood?
|
Bound to hemoglobin
|
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How does O2 move in and out of blood?
|
Through the dissolved compartmet
|
|
What is the total amount of hemoglobin in the blood equal to?
|
The amount dissolved plus the amount bound to hemoglobin
|
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How is CO2 transported in the blood?
|
Dissolved in plasma, as bicarbonate, and bound to hemoglobin
|
|
How is most CO2 transported?
|
In the form of bicarbonate
|
|
Is CO2 poorly or highly soluble in water?
|
Highly soluble in water
|
|
In the RBC, the reaction of CO2 and water is catalyzed by what?
|
Carbonic anhydrase
|
|
Does CO2 show saturation kinetics on a graph?
|
No
|
|
Can deoxygenated hemoglobin carry more or less CO2 as carbamino?
|
Can carry more CO2
|
|
What type of curve is the relationship between PCO2 and CO2?
|
Linear--no saturation kinetics
|
|
Can you average the PO2's from two different samples?
|
No, you have to average the O2 content of the samples to see what the resulting PO2 of the sample is
|
|
Can you average the PCO2's from two different samples?
|
Yes, because it is a linear relationship
|
|
What is P50?
|
The PO2 at which hemoglobin is 50% saturated with O2
|
|
What are 3 things that lower the affinity for O2?
|
H+ ion concentation, temperature, and PCO2
|
|
In tissues, is H+ concentration high or low?
|
High
|
|
In tissues, is temperature high or low?
|
High
|
|
In tissues, is HbCO2 high or low?
|
High
|
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When H+, temperature, and HbCO2 are all high, what happens to the O2 saturation curve?
|
It shifts to the right because the affinity is lowered
|
|
What does lowering the affinity for O2 mean?
|
Favors the unloading of O2
|
|
In the lungs, is the H+ concentration high or low?
|
Low
|
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In the lungs, is the temperature high or low?
|
Low
|
|
In the lungs, is the HbCO2 low or high?
|
Low
|
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What does the H+ concentration, temperature, and HbCO2 all being low do to the O2 saturation curve?
|
It shifts it to the left because of increased affinity
|
|
What does a high affinity for O2 mean?
|
It favors loading of O2 and unloading of CO2
|
|
In the alveolar capillaries, is O2 loaded or unloaded into blood?
|
Loaded into blood
|
|
In the alveolar capillaries, is CO2 loaded or unloaded into blood?
|
Unloaded from blood
|
|
In the tissue capillaries, is O2 loaded or unloaded from the blood?
|
Unloaded
|
|
In the tissue capillaries is CO2 loaded or unloaded into the blood?
|
Loaded
|
|
In alveolar capillaries, what is the H+ concentration and temperature?
|
Both are low
|
|
In the tissue capillaries, what is the H+ concentration and temperature?
|
Both are high
|
|
What is the cooperative effect?
|
When one gas is removed from the blood, it enhances the uptake of the other
|
|
In the lungs, the removal of CO2 does what to the O2 concentration?
|
It promotes the uptake of O2 which raises the affinity
|
|
What does 2,3 DPG do to O2 affinity and which way does it shift the curve?
|
It lowers O2 affinity shifting the curve to the right
|
|
What does hypoxia do to 2,3 DPG?
|
Increases the level of 2,3 DPG
|
|
What is a good way to estimate the PO2 inside an organ?
|
Measure the PO2 in the venous blood from that organ
|
|
What volume % of O2 does arterial blood contain?
|
20 vol %
|
|
What vol % of O2 does venous blood contain?
|
15 vol %
|
|
What is the normal PVO2?
|
40
|
|
What is the Hb-O2 curve for anemia compared to a normal curve?
|
Lower than normal
|
|
What does CO do to the O2 saturation curve?
|
It shifts it to the left---increases the affinity for O2
|
|
How is the amount of O2 that is taken up from the blood determined?
|
By the rate of perfusion of pulmonary capillaries
|
|
Is O2 perfusion or diffusion limited?
|
Pefusion limited
|
|
Is CO2 perfusion or diffusion limited?
|
Diffusion limited
|
|
What does the pulse oximeter tell us?
|
The saturation of hemoglobing ONLY!
|
|
What is the affinity of hemoglobin regulated by?
|
2,3 DPG
|
|
Does fetal hemoglobin have a high or low affinity for O2?
|
High affinity
|
|
What are the two variables regulated in the respiratory system?
|
H+ in the blood and H+ in the brain interstitium
|
|
Is the blood PO2 subject to control?
|
Only if the PO2 is dangerously low
|
|
What are the 2 sets of chemsensors?
|
The carotid bodies and the central sensor that is located in the brainstem
|
|
What are the carotid bodies detectors of?
|
Blood H+ and blood PO2
|
|
What are the central chemsosensors sensitive to?
|
The H+ in the brain interstitial fluid
|
|
What does the controller do?
|
Receives inputs from the chemosensors and regulates the activity of the respiratory muscles
|
|
What does the effector do?
|
Muscles that control ventilation; dipahragm and intercostal muscles
|
|
What do the sensors in the carotid bodies repspond to?
|
Blood H+, blood PCO2, and blood PO2 (only responds to PO2 when it is low)
|
|
When CO2/H+ increases in the brainstem, what do central chemoreceptors do?
|
Increased ventilation
|
|
Does CO2 move freely across the blood brain barrier?
|
Yes
|
|
What are the respiratory chemorecptors mainly driven by in the blood and brain interstitum?
|
H+ concentration
|
|
What does increasing the number of H+ ions in the blood do to ventilation?
|
It increased ventilation
|
|
What degree of hypoxia must be present for PO2 to increase ventilation?
|
Moderate to sever hypoxia
|
|
Does the response to hypoxia ever adapt?
|
No
|
|
What does the combination of high H+ and hypoxia do to respiratory drive?
|
Increases it
|
|
What does an increase in ventilation do to H+?
|
Lowers H+ causing respiratory alkalosis
|
|
What does a decrease in ventilation do to H+?
|
Increases H+ causing respiratory acidosis; will also cause hypoxemia and elevated CO2
|
|
What does fever do to ventilation?
|
Increased ventilation
|
|
What does mild hypothermia do to ventilation?
|
Increased ventilation
|
|
What does severe hypothermia do to ventilation?
|
Decreases ventilation
|
|
What does brain injury or drug overdose do to ventilation?
|
Depresses ventilation
|
|
What does painful stimuli do to ventilation?
|
Increases ventilation
|
|
What does panic do to ventilation?
|
Can result in hyperventilation
|
|
What are some drugs that reduce respiratory drive?
|
Alcohol
Opiates Benzodiazepines Barbituates Anesthetics |
|
What are some drugs that increase respiratory drive?
|
Cocaine
Amphetamine Caffeine Cyanide |
|
What is Zone 1 in the lung?
|
Defined as the region that is not perfused and it at the apex of the lung
|
|
What is the arterial pressure in Zone 1?
|
Zero
|
|
What is Zone 2?
|
Region that is perfused but perfusion is independent of Pv
|
|
What is Zone 3?
|
Region where perfusion is determined by both Pa and Pv and is located at the base of the lung
|
|
Is the perfusion pressure constant in Zone 3?
|
Yes--8 cm H2O
|
|
Does the resistance to blood flow decrease or increase as you move to the bottom of the lung?
|
Resistane decreases
|
|
Where is perfusion of the lung smallest?
|
At the top of the lung
|
|
Where is perfusion of the lung the greatest?
|
At the base of the lung
|
|
What is one way to collect an alveolar gas sample?
|
Long slow exhalation
|
|
What is the A-a gradient a good measurement of?
|
Lung function or disease
|
|
When is gas exchange ideal?
|
When there is uniform distribution of V and Q
|
|
What does the number 0.8 represent?
|
A perfect match of V and Q
|
|
What does Q but no V represent?
|
Perfusion but no ventilation; shunt
|
|
What does V but no Q represent?
|
Ventilation but no perfusion; dead space
|
|
What part of the lungs receives the best perfusion and ventilation?
|
The bottom of the lungs
|
|
Does the bottom of the lungs have a high or low V/Q ratio?
|
Low ratio--meaning it is overperfused and acting somewhat shunt like
|
|
Does the top of the lungs have a high or low V/Q ratio?
|
High ration--meaning it is over ventilated acting somewhat like dead space
|
|
What is the V/Q ratio in the bottom of the lungs?
|
0.3
|
|
What is the V/Q ration in the top of the lungs?
|
3.o
|
|
Which part of the lung is overperfused and under ventilated?
|
The bottom
|
|
Which part of the lung is over ventilated and under perfused?
|
The top of the lung
|
|
What part of the lung acts like a shunt?
|
the bottom of the lung
|
|
What part of the lung acts like dead space?
|
The top of the lung
|
|
What does perfusion do to CO2?
|
Brings it into the lungs
|
|
What does ventilation do to CO2?
|
Takes it out
|
|
If the flow is large, what will the PCO2 be?
|
Large also.....the bigger the flow the higher the PCO2
|
|
Where there is V but no Q, what is PCO2?
|
Zero
|
|
Where there is Q but no V, what is PCO2?
|
Same as venous blood, 46
|
|
When the V/Q ratio is high, what is the PCO2?
|
Low
|
|
Ventilation does what to O2?
|
Brings it in
|
|
Perfusion does what to O2?
|
Takes it out
|
|
When there is V but no Q, what is O2?
|
Same as room air, 150
|
|
When there is Q but no V, what is O2?
|
Same as venous blood, 40
|
|
If Q is large, what is PO2?
|
Low
|
|
When the V/Q ratio is high, what is the PO2?
|
High
|
|
A lung unit with low V/Q ratio has what PCO2 and what PO2?
|
A low PO2 and a high PCO2
|
|
A lung unit with a high V/Q ratio has what PCO2 and what PO2?
|
A low PCO2 and a high PO2
|
|
What does a V/Q ratio of 0 represent?
|
Airway obstruction
|
|
What does a V/Q ratio of infinity represent?
|
Pulmonary embolus
|
|
Is the PO2 in the top of the lungs low or high?
|
High
|
|
Is the PCO2 in the top of the lungs high or low?
|
Low
|
|
Is the PO2 in the bottom of the lungs low or high?
|
Low
|
|
Is the PCO2 in the bottom of the lungs low or high?
|
High
|
|
If V is greater than Q, that means....
|
Over ventilated (top of the lungs)
|
|
If V is less than Q, that means......
|
Over perfused (bottom of the lungs)
|
|
What is a normal A-a gradient?
|
0.8 mmHg
|
|
What is the PaO2, A-a gradient, and PaCO2 in an umcompensated, low V/Q mismatch?
|
Low PaO2
Large A-a gradient High PCO2 |
|
What are the compensation mechanisms for V/Q mismatches?
|
Hypoxia causes vascular smooth muscular contraction
Low PaCO2 causes bronchial smooth muscle contraction Hypoxia and hypercapnia both increase ventilation |
|
What does elevated PCO2 cause?
|
An increase in ventilation
|
|
What are some causes of low V/Q mismatches?
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Emphysema
Bronichitis Asthma |
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What is the normal A-a gradient?
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8 mmHg
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As we get older, what happens to our A-a gradient? Why?
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It gets larger because of normal wear and tear on our lungs
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What A-a gradient is suggestive of lung disease?
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20 or more
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What are the 5 causes of hypoxemia?
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Breathing air w/ low PO2
Hypoventilation Shunts Low V/Q mismatch Diffusion probelm |
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What is an example of breathing air w/ low PO2?
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High altitude
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What is the A-a gradient in a patient breathing air w/ low PO2?
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Normal
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What is an example of hypoventilation?
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Brain damage, drugs
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What is the A-a gradient in a pt that is hypoventilating?
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Normal
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What are the CO2 and O2 levels in a patient that is hypoventilating?
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Hypercapnia and hypoxemia
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What is the A-a gradient in a pt with a shunt?
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Large
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What is the A-a gradient in a pt with a low V/Q mismatch?
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Large
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What is an example of a patient with a low V/Q mismatch?
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COPD
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How do you tell the difference between a shunt and a low V/Q mismatch?
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A person with a shunt will have minimal change in their PO2 when given 100% O2; a person with a low V/Q mismatch will respond very well to 100% O2
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What are shunts caused by?
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Filling your lungs with fluid, pus, vomit, or other liquids
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What is a cause of a high V/Q ration?
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Pulmonary embolus
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If a person has poor response to administration of 100% O2, what do they have?
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A R-L shunt
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If a person responds very well to administration of 100% O2, what do they have?
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A low V/Q mismatch
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