1.
Bronchoconstriction during an asthmatic
attack reflects:
Correct Answer
B. A decrease in the diameter of the conducting zone airways
Explanation
B is correct
A is wrong because the respiratory zone has no smooth muscle
C is wrong because bronchoconstriction deals with smooth muscle not with alveolar sacs.
D is wrong because reistance in the airways actually INCREASES with bronchoconstriction
E is wrong because the diffusion of respiratory gases occurs
in the respiratory zone at the alveoli. Bronchoconstriction does not occur at this location
2.
The compliance of the lung is:
Correct Answer
A. Decreased in a premature infant with inadequate secretion of surfactant
Explanation
A is correct because Surfactant decreases the surface tension and thereby increases the compliance of the Lung. Premature infants often lack adequate secretion of surfactant
B is incorrect because compliance varies with the size of the lung and therefore also with the volume of the lung
C is incorrect because at RV or TLC the compliances are actually low and we rarely fill our lungs to tlc because of the very high energy cost
D is wrong because Emphysema actually INCREASES the Compliance--unfortunately this increase makes the peripheral airway diameters more dependent on extra-alveolar pressures and may create a Starling resistor which causes resistance to airflow
E is incorrect because FRC changes with Compliance. For example as compliance decreases it tends to reduce the FRC as well
3.
Which of the
following comparisons is correct at mid-inspiration during exercise?
(Patm = atmospheric pressure, Ppl = intrapleural pressure, PA =
alveolar pressure and Pm = mouth pressure). Be sure all indicated relationships (>, <, =) are correct.
Correct Answer
E. Patm > Ppl < PA < Pm
Explanation
E is correct because during inspiration regardless of excercise the pressure must be greater in the mouth than it is in the alveoli in order to create a gradient for air flow. Also the pleural pressure is negative and there for less than atmospheric pressure and alveolar pressure. E is the only choice that accounts for these conditions
4.
The conducting
airways:
Correct Answer
B. Contain ciliated cells and mucus-secreting cells.
Explanation
B is correct because the upper airways of the conducting zone contain ciliated cells and mucus-secreting cells.
A is incorrect because the conducting airways contain smooth muscle
C is incorrect because the respiratory bronchioles are part of the respiratory zone
D is incorrect because it is type II cells that secrete surfactant and furthermore they are found within the alveoli which are not part of the conducting zone
E is incorrect because the conducting zone has no capacity to senst the atmoshperic oxygen concentration
5.
The respiratory quotient (RQ):
Correct Answer
D. Is calculated as the amount of CO2 produced divided by the amount of O2 consumed
Explanation
D is correct because RQ = CO2 produced / O2 consumed
A is incorrect because it refers to the amount of CO2 produced
B is incorrect because an RQ of .7 would indicated a diet of only fats. A diet of only carbohydrates would be ~ 1.0
C is incorrect because the RQ actually drops as you increase your fat intake
E is incorrect because the value changes depending on diet and metabolic demand
6.
The instantaneous rate of diffusion of oxygen (the
number of O2 molecules diffusing per second) from the lung into the
blood is DECREASED by:
Correct Answer
E. The presence of carbon monoxide (CO)
Explanation
E is correct because the presence of carbon monoxide would decrease the affinity of Oxygen to bind to Hb
A is incorrect because an increase in surface are of the lung would actually INCREASE the rate of diffusion
B is incorrect because an increase in the concentration gradient would also likewise INCREASE the rate of diffusion
C is incorrect because it should say an INCREASE in the thickness of the membrane to be true
D is a junk answer. Hb is always present in the red blood cell
7.
The alveolar pressure is:
Correct Answer
A. Equal to atmospheric pressure whenever there is no flow
Explanation
A is correct
B is incorrect because to be at rest alveolar pressure must be equal to atmospheric pressure
C is incorrect because if alveolar pressure were subatmospheric the pressure gradient would cause INSPIRATION
D is incorrect because the pleural pressure is usually around -4 mm Hg and alveolar is usually around 100 mm Hg
8.
What is the correct
sequence of events for inspiration to occur?
1.
activation of inspiratory muscles
2.
decrease in alveolar pressure
3.
increase in lung volume
4.
activation of DRG inspiratory neurons (premotor neurons
in the brainstem)
5.
increase in the size of the thoracic compartment
6.
decrease in pleural pressure
Correct Answer
A. 4, 1, 5, 6, 3, 2
9.
The alveoli
in the apex of the lung in the upright posture are relatively distended at FRC
because:
Correct Answer
C. Their compliance is relatively high.
Explanation
C is correct
A is incorrect because the pleural pressure at the apex is more negative than that at the base
B is incorrect because FRC is defined when all muscles are relaxed
D is incorrect because the question asked about distendability not resistance to airflow
10.
To generate high velocity expiratory flow during a
cough, you would need to activate the:
Correct Answer
D. Abdominal muscles
Explanation
D is correct
A and B are incorrect because the external intercostal muscles and the diaphragm activate during INSPIRATION
The muscles used for forced expiration are the abdominal muscles and the internal intercostals. D is the only option
11.
The presence of surfactant:
Correct Answer
D. Increases the lung compliance
Explanation
D is correct
A is incorrect because Surfactant DECREASES surface tension
B is incorrect because it is Type II cells that secrete surfactant
C is incorrect because it prevents collapse
E is incorrect because it does not occur in the intrapleural space
12.
In a person that was seated and at rest, a
tight-fitting corset would be expected to decrease all of the following EXCEPT:
Correct Answer
A. Tidal volume
13.
With a tidal volume of 700 mL, a dead space of 200 mL
and a respiratory frequency of 20, the alveolar
minute ventilation would be:
Correct Answer
B. 10 Liters
Explanation
VA =RF (VT-VDS)
=20 (700-200)
=10,000 ml
=10 L
14.
Which of the following statements is TRUE?
Correct Answer
A. Mixed venous blood is usually 75% saturated with oxygen
Explanation
A is correct
B is incorrect because increased hemoglobin concentrations has no affect on the % Hb saturation
C is incorrect becaus it is 10% of CO2 that is transported in the dissolved form--O2 is much less than that I beleive
D is incorrect because the reverse is true
E is incorrect becase the arterial PCO2 is normally about 40, 46 is a tad high
15.
In
patients with respiratory acidosis, you would expect:
Correct Answer
C. Their hemoglobin-oxygen saturation curve to be shifted to the right
Explanation
Remember the curve shifts to the right with an increase in the following values (CO2, [H+], Heat, 2,3-BPG)
16.
Most of the carbon dioxide produced by cells is
transported in the blood as:
Correct Answer
C. HCO3-
Explanation
you better know this one
17.
A patient that has a spinal cord transection at the
level of the first thoracic vertebrae (T1) would be able to breathe using
their:
Correct Answer
B. Accessory muscles and diaphragm
Explanation
accessory muscles are innervated by CN 11 and the diaphram by the phrenic nerve (C3,4,5) These would still be intact after a T1 transection. all other muscles such as the intercostals and abdominals would be wiped out
18.
The basic respiratory rhythm is generated in
the:
Correct Answer
A. Medulla
19.
If I were to fly you to Denver (I’d be a really nice
guy) and then immediately take you to an elevation of about 10,000 feet (maybe
not such a nice guy!), I would expect your alveolar Po2 to be about 60 mm Hg and your ventilation to
_____________(compared to that in Kentucky) and your arterial Pco2
to ___________ (compared to that in Kentucky).
Correct Answer
D. Increase , decrease
Explanation
see notes on group discussion
20.
A patient with respiratory complications which result
in a decreased surface area in the lung apex might experience respiratory
difficulty:
Correct Answer
A. . in the head-down position
Explanation
Blood flow is to the alveoli is usually greater at the base of the lung due to gravity. However, if you turn a person upside down the majority of the blood flow will be at the apex and therefore respiration will depend on the apex more for diffusion of gases. the diffusion of gases required high surface area (as well as a concentration gradient and thin wall)
21.
In a person
with a thickened alveolar – capillary membrane, which of the following
comparisons is TRUE?
Correct Answer
D. Atmospheric Po2 > dead space Po2 > alveolar Po2 > arterial Po2 > venous Po2