Term
| A patient blows into a spirometer as hard and fast as possible. You notice that the FEV1 of the patient is only 1.1L, about 30% of their FVC. This patient could have... |
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Definition
| Obstructive pulmonary disease (Emphysema) |
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Term
A patient blows into a spirometer as hard and fast as possible. You notice that although the FEV1 of the patient is 87% of their FVC, the total volume of air expired (FVC) is about 3L. You suspect that the patient has...
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Definition
| Restrictive pulmonary disease (Fibrosis) |
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Term
| How does pulmonary circulation keep resistance low even in the face of an increased CO (as in exercise)? |
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Definition
| Additional capillary channels are opened, increasing the number of parallel vessels and thus lowering resistance. |
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Term
| These vessels bring and take blood from alveolar vessels. They become compressed with expiration. |
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Definition
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Term
| These vessels deal with blood delivery/removal from alveoli. They are compressed with inspiration. |
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Definition
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Term
| Why is the oxygen tension of blood in the left atrium slightly lower than the oxygen tension of blood in the early pulmonary veins? |
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Definition
| Bronchiole veins empty into the pulmonary veins, slightly mixing in deoxygenated blood (PvO2=40mmHg) with oxygenated blood (PvO2=100mmHg). |
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Term
| Which extravascular force in the lung help keep extra alveolar vessels open at high lung volumes? |
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Definition
| radial traction on the extra alveolar vessels. |
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Term
In the top of the lung (zone 1) which vessel has the highest pressure?
A)Pa
B)Pv
C)PA |
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Definition
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Term
In the middle of the lung (zone 2) which vessel has the highest pressure?
A)Pa
B)Pv
C)PA
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Definition
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Term
In the bottom of the lung (zone 3) which vessel has the lowest pressure?
A)Pa
B)Pv
C)PA
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Definition
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Term
| What does FIO2 stand for and what is its normal value? |
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Definition
| Fraction of Oxygen in the atmosphere. 21% |
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Term
What does PIO2 stand for and what is its normal value?
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Definition
| Partial pressure of inspired oxygen. 150mmHg |
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Term
What does PAO2 stand for and what is its normal value?
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Definition
| Partial pressure of oxygen in the alveoli. 100mmHg |
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Term
What does PaO2 stand for and what is its normal value?
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Definition
| Partial pressure of oxygen in the pulmonary veins. 90mmHg |
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Term
What does PvO2 stand for and what is its normal value?
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Definition
| Partial pressure of oxygen in pulmonary arteries. 40mmHg. |
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Term
What does PaCO2 stand for and what is its normal value?
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Definition
| Partial pressure of carbon dioxide in pulmonary arteries. 40mmHg. |
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Term
What does PvCO2 stand for and what is its normal value?
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Definition
| partial pressure of oxygen in the pulmonary veins. 46mmHg |
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Term
What does CaO2 stand for and what is its normal value?
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Definition
| The content of oxygen in the blood as a volume. 20.6ml O2/100ml blood. |
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Term
How can one calculate the PIO2 in an individual?
How can this be used to calculate PAO2? |
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Definition
PIO2=(PB-PH2O)xFIO2 normally 150mmHg
PAO2=PIO2-PCO2 normally 100mmHg |
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Term
| Is oxygen or CO2 more soluble in the alveoli? How is this difference made up? |
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Definition
CO2. O2 has a larger pressure driving force:
PAO2-PvO2=100mmHg-40mmHg=60mmHg
PvCO2-PACO2=46mmHg-40mmHg=6mmHg |
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Term
| When the membrane of the alveoli is the restriction for a substance's diffusion into the blood, this is a... |
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Definition
| diffusion limited substance (e.g. is carbon monoxide) |
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Term
| When the flow of blood is the limiting factor to a substance's entry into the bloodstream, this is called... |
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Definition
| A perfusion limited substance (e.g. is nitric oxide) |
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Term
| Why are O2 partial pressure changes more drastic than CO2 changes in a person with a diffusion impairment? |
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Definition
| higher than normal CO2 levels induce hyperventilation to blow off extra CO2 while O2 does not have this effect in and of itself. |
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Term
A decreased V/Q ratio indicates what type of pulmonary disease?
How does this occur? |
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Definition
Obstructive pulmonary disease (emphysema).
Ventilation ceases, lowering PAO2 and raising PACO2 slightly. Thus, ventilation decreases while flow remains unchanged. |
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Term
an increased V/Q ratio indicates what kind of pulmonary disease?
How does this occur? |
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Definition
A restrictive pulmonary disease (fibrosis).
PAO2 increases, but PCO2 becomes 0 because there is little to no perfusion. Thus, V/Q approaches infinity. |
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Term
| How is it that the top of the lung has a higher V/Q ratio than the bottom of the lung? |
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Definition
| Ventilation decreases as you ascend along the lung, but perfusion decreases even more. |
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Term
| A brain trauma patient becomes hypoxic. What is a likely cause? |
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Definition
| hypoventilation (causes pCO2 to increase) |
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Term
A patient suffering from pulmonary edema suffers from hypoxemia. What is the cause?
What would this person's PACO2 value be? |
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Definition
| Impaired diffusion. PACO2 will probably be 40mmHg if not extremely severe and with hyperventilation. |
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Term
| A patient is suffering from tachypnea. is it safe to assume that they are hypoxic? |
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Definition
| No. Measure pCO2 via a pulse oximeter. |
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Term
| A young infant is cyanotic and has a high breathing rate. What is a possible cause? |
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Definition
| anatomic shunt (patent foramen ovale) |
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Term
| A chronic smoker suffers from hypoxia. what is a possible cause? |
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Definition
| Ventilation- perfusion inequality due to emphysema |
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Term
| What would the PO2, blood saturation level and blood oxygen content levels in a patient do in anemia? |
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Definition
PO2=nothing
SAT=nothing
Content=reduced (less Hb) |
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Term
What would the PO2, blood saturation level and blood oxygen content levels in a patient do in CO poisoning?
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Definition
PO2=nothing
SAT=go down (CO competition for Hb)
Content=go down (less free Hb) |
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Term
What would the PO2, blood saturation level and blood oxygen content levels in a patient that lives in the mountains of Colorado?
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Definition
PO2=go down (FIO2 is reduced at high altitude)
SAT=go down (Less available O2)
Content=go down slightly, but return to normal (more Hb would be made with chronic hypoxia) |
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Term
| What factors induce Hb release of O2? |
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Definition
Temperature,
dropped pH
Increased CO2 levels
Increased BPG levels |
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Term
| How is most CO2 transported in the bloodstream? |
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Definition
| Transported as carbonic acid (90% arteriolar, 60% venous) |
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Term
| Decreased O2 levels and increased CO2 levels in an arteriole does what to arteriolar capillaries surrounding it? |
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Definition
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Term
| why does pulmonary artery pressure increase in patients with emphysema? |
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Definition
| Large portions of the capillary bed are destroyed, decreasing the number of available parallel vessels to decrease resistance. Also, widespread hypoxia induces constriction of the alveolar capillaries. Hypoxia also induces polycythemia, increasing blood viscosity. Lastly, radial traction is lost, keeping lung volume chronically high and the arteriolar vessels compressed even more. |
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Term
| Why is there a small tendency for fluid leakage into the lung interstitium? |
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Definition
| higher than normal interstitial oncotic pressure just out paces capillary hydraulic pressure, causing net filtration. Keeping alveoli free from this fluid via lymphatics is key to maintaining this oncotic pressure. |
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Term
| What can cause pulmonary edema? |
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Definition
increased capillary hydrostatic pressure (heart failure, MI, etc.)
increased capillary permiability
decreased lymph drainage
decreased interstitial oncotic pressure (causes fluid to leak directly into alveoli). |
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Term
| Which spinal nerves give rise to the phrenic nerve? |
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Definition
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Term
| Which brain stem section is responsible for the quality of a respiratory breath (breath is on time and proper inspiration/expiration depth) |
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Definition
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Term
| Which brain stem section is responsible for maintaining the proper breathing rate? |
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Definition
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Term
| Which brain stem section is responsible for the actual initiation of breathing? |
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Definition
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Term
| When are the dorsal nerve groups most actively firing? What other nerve group that is attached to the glossopharyngeal and vagus nerves is associated with this the dorsal nerve group? |
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Definition
Initiating inhalation.
Nucleus of the tractus solitarius. |
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Term
| These lung receptors sense interstitial pressure. |
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Definition
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Term
| Why can't the chemosensitive regions of the brain stem detect O2 levels like the carotid chemoreceptors? |
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Definition
| O2 cannot directly cross the blood brain barrier while CO2 can. |
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