Respiratory Physiology 2023

Question 1 of 74

Which of the following will increase the alveolar ventilatory response to an increase in PaCO2?

General anesthesia
Chronic obstructive pulmonary disease
Sleep
Metabolic acidosis
Morphine

Question 2 of 74

What is the term for the compensatory mechanism of widening pulmonary vasculature in response to increased pulmonary arterial pressure?

Retention
Pulmonary hypertension
Distention
Recruitment
Elongation

Question 3 of 74

Which of the following pneumocytes are immature in premature infants causing trouble with alveolar ventilation?

Type I
Type II
Type IV
Type V
Type III

Question 4 of 74

Which of the following is NOT cause hypoxemia?

An A-a gradient of 7 mmHg
A decreased partial pressure of inspired O2
Right to left shunt
Diffusion impairment
V/Q inequality

Question 5 of 74

Which of the following changes will NOT occur at high altitude?

Respiratory acidosis
Increased cardiac output
Increased red cell mass
Decreased plasma volume
Hyperventilation

Question 6 of 74

Which type of respiratory neural inputs are found outside of the lungs?

Central chemoreceptors
Bronchial C-fibers
Juxta-capillary receptors
Lung stretch receptors
Irritant receptors

Question 7 of 74

What process causes increased pulmonary vascular resistance at high lung volumes?

The supply vessel dilation effect
Left ventricular hypertrophy
Right ventricular hypertrophy
The capillary compression effect
The left heart compression effect

Question 8 of 74

What is the most important driver of the respiratory cycle?

Large surface tension in the fluid on the alveolar walls
Negative pleural pressure
Alveolar ventilation changes that are caused by the upward movement of the diaphragm
Compliance differences within the lungs
Airway diameter changes which facilitate spontaneous airflow

Question 9 of 74

The alveolar to arterial oxygen gradient should be less than which of the following to be considered a non-pathologic shunt?

10 mmHg
15 mmHg
7 mmHg
12mmHg
5 mmHg

Question 10 of 74

A person comes to you with the complaint that whenever he ascends to higher altitudes, he starts having a headache and dizziness. He also starts vomiting occasionally. Which of the following is the best choice for symptom control?

Captopril
Acetazolamide
Omeprazole
Nifedipine
Atropine

Question 11 of 74

Which of the following ions do the central chemoreceptors sense?

Potassium
Magnesium
Sodium
Hydrogen
Calcium

Question 12 of 74

How many oxygen molecules can bind to one hemoglobin protein?

4
1
2
5
3

Question 13 of 74

Which of the following will NOT show a prolonged forced expiration on pulmonary function testing?

Emphysema
Asthma
Aspirated foreign object
Pulmonary edema
Chronic bronchitis

Question 14 of 74

A patient in the ICU has an ABG sent for analysis. Test results show a PaO2 of 93 mmHg, PaCO2 of 38 mmHg, and a barometric pressure of 750 mmHg. What is the A-a gradient?

13 mm Hg
9 mm Hg
6 mm Hg
8.2 mm Hg
7.0 mm Hg

Question 15 of 74

A mountain climber comes to you with the complaint that while he was climbing a mountain he started having hallucinations and felt dizzy. Which of the following would best explain the pathophysiology of his symptoms?

Increased permeability of blood-brain barrier
Hypoventilation
Tachycardia
Increased number of red blood cells
Decreased carbon dioxide in the blood

Question 16 of 74

Where is the pneumotaxic center located?

In the pons
In the medulla
In the cerebrum
In the cerebellum
In the lungs

Question 17 of 74

Why does the oxygen-hemoglobin dissociation curve have a sigmoidal shape?

As each oxygen binds to hemoglobin the dissolved content of oxygen decreases.
As each oxygen binds to hemoglobin the dissolved content of oxygen increases.
As each oxygen binds to hemoglobin the affinity for the next oxygen is increased.
As each oxygen binds to hemoglobin the affinity for the next oxygen is decreased.
As each oxygen unloads from hemoglobin the affinity for the next oxygen is increased.

Question 18 of 74

Which of the following statements is true for Poiseuille’s law?

Resistance is not affected by the diameter of the tube.
Resistance is inversely proportional to the radius to the fourth power.
Resistance is eight times the length of the tube.
Resistance is nine times the radius of the tube.
Resistance is inversely proportional to viscosity.

Question 19 of 74

Which of the following will increase the uptake of oxygen in the blood?

A decrease in PA02 to 50 mmHg
An increase in PA02 above 100 mmHg
A decrease in blood flow through the lungs
An increase in blood flow through a right-to-left shunt
An increase in cardiac output

Question 20 of 74

Which of the following is NOT part of the pathophysiology of high-altitude pulmonary edema?

Filling of alveoli with fluid
Vasoconstriction of pulmonary arteries
Vasodilation of pulmonary arteries leading to spillage of blood
Increase in pulmonary artery pressure
Stress failure of pulmonary capillaries

Question 21 of 74

Which of the following types of channels are present on type-I glomus cells?

Oxygen-dependent calcium channels
Oxygen-dependent sodium channels
Oxygen-dependent magnesium channels
Oxygen-dependent chloride channels
Oxygen-dependent potassium channels

Question 22 of 74

Which of the following variables changes when a person with polycythemia is at 100% saturation?

The dissolved arterial oxygen content
The oxygen concentration
The bicarbonate concentration
The partial pressure of oxygen
The partial pressure of carbon dioxide

Question 23 of 74

Which of the following changes does NOT occur in emphysema?

Pleural pressure is always less than alveolar pressure.
Dynamic obstruction of the airways takes place.
The airways are dynamically decompressed.
Airway resistance is increased.
Elastic recoil of the lungs is decreased.

Question 24 of 74

Which zone of the upright lung is best described by the following pressures: Pa > PA > Pv?

Zone 3
Zone 2
Zone 1
Zone 5
Zone 4

Question 25 of 74

The pathophysiology of acute mountain sickness is not yet fully understood. However, which of the following is a major factor in the development of acute mountain sickness?

Anemia
Acidosis
Hypoxia
Hypercarbia

Question 26 of 74

Which of the following types of channels open after depolarization of glomus cells at low partial pressures of O2?

L-type chloride channels
T-type calcium channels
L-type potassium channels
L-type sodium channels
L-type calcium channels

Question 27 of 74

Which of the following are the normal values for PaCO2, PACO2, and PvCO2 respectively?

46 mmHg, 40 mmHg, 40 mmHg
40 mmHg, 95 mmHg, 100 mmHg
40 mmHg, 40 mmHg, 46 mmHg
90 mmHg, 40 mmHg, 46 mmHg
100 mmHg, 95 mmHg, 40 mmHg

Question 28 of 74

Which of the following is true regarding the relationship between alveolar ventilation and PACO2?

As PACO2 increases so will alveolar ventilation.
They are directly proportional.
They do not affect each other.
They are inversely proportional.
They are only inversely proportional between a PACO2 of 40 – 50 mmHg.

Question 29 of 74

Which of the following happens as you descend into the water?

The gas partial pressures in the blood will decrerase.
The gas partial pressures in the lungs will decrease.
The gas volume and partial pressure will increase.
The gas partial pressures in the lungs will increase.
The gas volume in the lungs will increase.

Question 30 of 74

Which of the following is the best option for the management of high-altitude cerebral edema?

Hypertonic saline solution
Hypotonic saline solution
Mannitol
Dexamethasone
Isotonic saline solution

Question 31 of 74

Which of the following changes will occur in the body in response to PO2 < 60 mmHg?

Normal breathing rate
Increase in ventilation
Decrease in carbon-dioxide
Decrease in ventilation
Relaxation of diaphragm

Question 32 of 74

Which of the following statements is NOT true regarding carbon dioxide transport in the blood?

Less carbon dioxide is bound to hemoglobin as compared to oxygen.
There is more CO2 dissolved in the blood than O2.
The majority of the carbon dioxide in the body is in the form of bicarbonate ions.
The solubility of oxygen is greater than carbon dioxide.

Question 33 of 74

Which of the following statements is NOT true regarding the surfactant?

It has polar and non polar sides.
It reduces surface tension.
It is a mixture of lipids and proteins.
It has only non polar sides.
It is produced by type II pneumocytes.

Question 34 of 74

Alveolar pressure will be lower than the arterial and venous pressures in which of the following zones of the lung?

Zone 3
Zone 1
Zone 5
Zone 4
Zone 2

Question 35 of 74

Which of the following is the generally accepted sequence of events leading to high altitude pulmonary edema (HAPE)?

Hypoxia => pulmonary vasoconstriction => pulmonary hypertension => stress failure of pulmonary capillaries => accumulation of extravascular fluid in the alveolar spaces that impairs gas exchange
The correct sequence is not listed.
Hypoxia => pulmonary vasoconstriction => stress failure of pulmonary capillaries => pulmonary hypertension => accumulation of extravascular fluid in the alveolar spaces that impairs gas exchange
Hypoxia => stress failure of pulmonary capillaries => pulmonary vasoconstriction => pulmonary hypertension => accumulation of extravascular fluid in the alveolar spaces that impairs gas exchange
Hypoxia => pulmonary hypertension => pulmonary vasoconstriction => stress failure of pulmonary capillaries => accumulation of extravascular fluid in the alveolar spaces that impairs gas exchange

Question 36 of 74

Which of the following causes an increase in alveolar ventilation?

Increase in blood flow
Decrease in carbon dioxide
Increase in PaCo2
Metabolic alkalosis
Increase in oxygen concentration

Question 37 of 74

Which are normal values for PAO2, PaO2, and PvO2 respectively?

95 mmHg, 100 mmHg, and 40 mmHg
50 mmHg, 95 mmHg, 40 mmHg
95 mmHg, 55 mmHg, 200 mmHg
40 mmHg, 95 mmHg, and 100 mmHg
100 mmHg, 95 mmHg, and 40 mmHg

Question 38 of 74

Which of the following does NOT occur in restrictive lung disease?

Decrease in lung compliance
Use of accessory muscles during respiration
Increase in respiratory rate
Increased negative pressure to fill the lungs
Greater residual lung volumes

Question 39 of 74

Which of the following parameters is increased in the apex of the lung?

Ventilation
Compression of alveoli
pH
Blood flow
The partial pressure of carbon dioxide

Question 40 of 74

What is the mechanism of holding the breath longer when a person hyperventilates?

It increases hydrogen ions, which decrease the stimulus to breathe.
It decreases PaO2, which decreases the stimulus to breathe.
It decreases CO2, which is the stimulus to breathe.
It increases CO2, which decreases the stimulus to breathe.
It increases CO2, which is the stimulus to breathe.

Question 41 of 74

What will happen to pulmonary vascular resistance when pulmonary vascular pressure increases?

It will stay the same.
It will decrease.
It will increase.
It will decrease, then increase.
It will increase, then decrease.

Question 42 of 74

Which of the following is the dissolved concentration of O2 in a normothermic patient, with a PaO2 of 90 mmHg?

0.295 mL of O2 per dL of blood
0.133 mL of O2 per dL of blood
0.124 mL of O2 per dL of blood
0.279 mL of O2 per dL of blood
0.325 mL of O2 per dL of blood

Question 43 of 74

Which of the following would you expect in a patient with obstructive lung disease?

Decreased work of breathing
Increased FEV1
Increased total lung volume
Increased vital capacity
Decreased total lung volume

Question 44 of 74

The ventilation-perfusion ratio is normal in which of the following zones of the lung?

Zone 2
Zone 1
Zone 5
Zone 4
Zone 3

Question 45 of 74

Which of the following pulmonary receptors is responsive to pulmonary edema?

Central chemoreceptors
Irritant receptors
Stretch receptors
Diaphragm receptors
J-receptors

Question 46 of 74

Which of the following factors shift the oxygen hemoglobin curve to the left?

High temperature
Decrease in pH
High concentration of CO2
Increase in 2,3 DPG
Increase in pH

Question 47 of 74

Which of the following will increase resistance?

Adding parallel circuits
Decreasing the length of a tube
Decreasing the viscosity of the flowing substance
Radial traction
Decreasing the diameter of an airway

Question 48 of 74

Which of the following PaCO2 levels correspond with decreased alveolar ventilation?

40 mmHg
10 mm Hg
50 mmHg
20 mmHg
30 mmHg

Question 49 of 74

Which of the following statements is TRUE for central sleep apnea?

It is caused by obstruction of the airways.
There is a decreased drive to breathe regardless of apnea.
There is no periodic cessation of breathing.
There is a drive to breathe when apnea occurs.
There is a change in pleural pressure.

Question 50 of 74

Which of the following factors will shift the oxygen hemoglobin curve to the right?

A decrease in pH
A decrease in body temperature
A decrease in 2,3 DPG
A decrease in hydrogen ion concentration
A decrease in CO2 concentration

Question 51 of 74

Which of the following will have the highest partial pressure of oxygen, at sea level?

Blood in the pulmonary vein
Alveolar air
Blood in the capillaries
Humidified tracheal air
Mixed venous blood

Question 52 of 74

When is the partial pressure of oxygen the greatest during a breath-hold dive?

Before the descent
When resting
During the ascent
At the start of the descent
At the apex of the dive

Question 53 of 74

Which of the following statements is TRUE regarding pulmonary vascular circulation?

Blood in the pulmonary artery has a low concentration of oxygen.
Blood in the pulmonary artery comes from the left ventricle.
Blood in the pulmonary artery has a high concentration of oxygen.
Blood in the pulmonary vein has a high concentration of carbon dioxide.
It has high resistance.

Question 54 of 74

Which of the following ions is bicarbonate exchanged for in a red blood cell?

Hydrogen
Sodium
Calcium
Potassium
Chloride

Question 55 of 74

Which of the following conditions increases diffusional capacity in the lung?

Increased diffusional distance
Lower gas solubility
A lower partial pressure gradient
Pulmonary fibrosis
Increased surface area

Question 56 of 74

Which of the following factors does NOT increase the breath-hold time?

Focusing on a task
Decreased oxygen demand
Increased lung volume and oxygen content
Hyperventilation
Activity during breath-hold diving

Question 57 of 74

Which of the following lung volumes has the lowest pulmonary vascular resistance?

Residual volume
Low lung volume
High lung volume
Total lung capacity
Moderate lung volume

Question 58 of 74

Which of the following describes alveolar pressure during inspiration and expiration, respectively?

Negative, negative
Positive, negative
Negative, positive
Zero, negative
Positive, positive

Question 59 of 74

How does a right-to-left shunt lead to hypoxemia?

Some venous blood bypasses the pulmonary circulation, which decreases PaO2.
Some venous blood bypasses the pulmonary circulation causing an increase in PaCO2.
It allows more blood to travel through the pulmonary circulation, causing a dilution in PaO2.
Some arterial blood bypasses the bronchial circulation, causing a decrease in Pa02.
It allows more blood to be channeled through under-ventilated areas of the lungs, causing a decrease in PaO2.

Question 60 of 74

Which of the following is a chronic adaptation to breath-hold diving?

An increased ventilatory response to PaCO2
An increased ventilatory response to PaO2
Diving tachycardia
An increased total lung capacity
A decreased inspiratory capacity

Question 61 of 74

Which of the following effects does NOT occur if the oxygen concentration is low in the pulmonary alveoli?

Vasoconstriction causes diversion of blood flow to more oxygenated alveoli.
Pulmonary blood vessels constrict in the area of low oxygen concentration.
Pulmonary blood flow is decreased due to vasoconstriction.
The resistance to blood flow increases due to vasoconstriction.
Pulmonary blood vessels dilate in response to low oxygen concentration.

Question 62 of 74

What is the alveolar ventilation of a patient who is breathing 15 times per minute and has a dead space volume of 300 ml and a tidal volume of 500 ml?

5000 ml/min
7500 ml/min
4500 ml/min
7200 ml/min
3000 ml/min

Question 63 of 74

What is the value of carbon dioxide concentration in the arterial blood in the systemic circulation?

0 mmHg
30 mmHg
10 mmHg
40 mmHg
20 mmHg

Question 64 of 74

Which of the following statements is CORRECT about V/Q matching?

A high V/Q ratio is always better.
A low V/Q ratio is always better.
Any V/Q mismatch will result in a lower overall PaO2.
If blood flow is restricted to a single alveolus, the resulting blood will have a decreased oxygen saturation.
Alveoli that have airway restriction will have a high V/Q ratio.

Question 65 of 74

Which of the following structures sets the central rhythm and frequency of inspiration?

The apneustic center
The dorsal respiratory group neurons
The pneumotaxic center
The caudal portion of the ventral respiratory group neurons
The carotid body receptors

Question 66 of 74

Which of the following statements regarding zone 1 of the lung is CORRECT?

Pressure in the veins is greater than in the arteries.
Low alveolar pressure induces the opening of the arterioles.
Pressure in the alveoli is less than the pressure in the arteries.
It has the highest amount of blood flowing through it.
It has the least amount of blood flowing through it.

Question 67 of 74

Which of the following would likely have the greatest compliance?

A lung with fibrosis at the apex of the lung
The base of an emphysematous lung
The apex of an emphysematous lung
The base of a fibrotic lung
The apex of a normal lung

Question 68 of 74

Which of the following is the a-v O2 gradient very dependent on?

Physiological shunting
Metabolism
Potassium concentration
Water vapor pressure
Sodium concentration

Question 69 of 74

Which of the following is a predictable acute effect of hypobaric hypoxia?

A decrease in the rate and depth of breathing
An increase in mean pulmonary artery pressure
A decrease in hemoglobin concentration
A decrease in urinary output
An increase in the partial pressure gradient of oxygen

Question 70 of 74

Where are the hydrogen ions produced that stimulate the central chemoreceptors?

In the CSF
In the cerebral arterioles
In the neuronal intracellular fluid
In the Schwann cells
In the astrocytes

Question 71 of 74

Which of the following statements is NOT true for zone 3 of the lung?

It has the highest amount of blood flowing through it.
Pressure on the venous end is greater than the alveolar pressure.
Pressure on the venous end is less than arterial pressure.
Pressure on the venous end is lower than the alveolar pressure.
Pressure on the arterial end is greater than the alveolar pressure.

Question 72 of 74

Which of the following is correct when comparing the CO2-hemoglobin dissociation curve to the O2-hemoglobin dissociation curves?

The Haldane effect is exhibited on the O2 curve but not the CO2 curve
Neither molecule affects the other molecule's curve.
They both have higher partial pressures on the arterial side than the venous side.
They are both sigmoidal in shape
The CO2 content is about double the O2 content.

Question 73 of 74

Which of the following is NOT a cause of hypoxia?

Increased fractional of inspired oxygen
Low cardiac output
Anemia
Low tissue perfusion
Hypoxemia

Question 74 of 74

Which of the following is NOT an effect of the hyperventilation response to hypobaric hypoxia?

Stimulation of central chemoreceptors
The depressed activity of central chemoreceptors
The decreased partial pressure of carbon dioxide in the arterial blood
Diffusion of carbon dioxide out of the cerebrospinal fluid
The decreased partial pressure of carbon dioxide in the alveolar gas

Respiratory Physiology 2023

Respiratory Physiology 2023

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