l

Here are the answers to your multiple-choice questions:

Question 1

Out of the following, where would you expect PO2 to be lowest?

* inferior vena cava (This blood has just returned from the systemic circulation, having delivered oxygen to the tissues.)

* left atrium

* alveoli

* pulmonary veins

Question 2

A low ventilation-perfusion (V/Q) ratio would:

* Increases PAO2

* Increase in PaO2

* Activate the cardiopulmonary reflex

* Decrease PaO2 (A low V/Q ratio means there is inadequate ventilation for the amount of blood flow, leading to less oxygen uptake and thus a lower partial pressure of oxygen in the arterial blood.)

Question 3

Which of the following is not a mechanism of CO2 transport in the circulation:

* Transported as a bicarbonate ion

* Dissolved in plasma

* Bound to albumin (While albumin can bind some substances, it's not a primary mechanism for CO2 transport. CO2 is primarily transported as bicarbonate, dissolved in plasma, or as carbaminohemoglobin.)

* As carbaminohemoglobin

Question 4

Which of the following would not initiate a rightward shift in the oxygen-hemoglobin dissociation curve:

* Decreased pH

* Decreased temperature (A decrease in temperature would cause a leftward shift, increasing hemoglobin's affinity for oxygen.)

* Increased temperature

* Increased CO2

Question 5

Pulmonary surfactant is secreted by:

* type II alveolar epithelial cells

* Alveolar macrophages

* Lymphocytes

* type I alveolar epithelial cells

Question 6

Which of the following is not a volumetric measure usually obtained during spirometry:

* Vital capacity

* Tidal volume

* Alveolar volume (Alveolar volume is a theoretical volume, not directly measured by spirometry as a distinct volumetric measurement. Spirometry measures capacities and volumes that involve air movement in and out of the lungs.)

* Inspiratory reserve volume

Question 7

Lung compliance is best defined as:

* Change in lung volume per change in transpulmonary pressure

* Change in lung volume per change in expiratory flow rate

* Change in transpulmonary pressure per change in lung volume.

* Change in transpulmonary pressure for a given expiratory flow.

Question 8

Afferent feedback from the peripheral chemoreceptors travels via:

* The phrenic and vagus nerve to the nucleus tractus solitarius

* The glossopharyngeal and vagus nerve to the nucleus tractus solitarius

* The phrenic and glossopharnyngeal nerve to the nucleus tractus solitarius

* The glossopharyngeal and vagus nerve to the cerebellum

Question 9

Which of the following is not considered in the alveolar gas equation?

* Atmospheric pressure

* Pulmonary artery pressure (The alveolar gas equation calculates the partial pressure of oxygen in the alveoli, primarily considering atmospheric pressure, water vapor pressure, and the partial pressures of oxygen and carbon dioxide.)

* Water vapour pressure

* PaCO2

Question 10

Mucociliary clearance relies on the motion of cilia to move mucus towards which structure:

* Alveolar macrophages

* Terminating bronchiole

* Nasal conchae

* Pharynx (The mucociliary escalator moves mucus and trapped particles up towards the pharynx to be swallowed or expelled.)

Question 11

During a period of drug-induced hypoventilation, which of the following would be true:

* Rise in PaCO2 and an increase in pH

* A decrease in PaCO2 and an increase in pH

* Rise in PaCO2 and a decrease in pH (Hypoventilation leads to CO2 retention, which increases PaCO2 and lowers pH due to the formation of carbonic acid.)

* A decrease in PaCO2 and a decrease in pH

Question 12

What is meant by the term 'physiologic' shunt?

* The shunt of blood from the pulmonary veins back into the pulmonary artery

* Where there is inadequate blood flow relative to alveolar ventilation (i.e. high V/Q).

* Where blood reaching the left heart is relatively deoxygenated due to inadequate gas exchange (i.e. low V/Q) (Physiologic shunt refers to blood that bypasses ventilated alveoli or goes through areas of very low V/Q, leading to deoxygenated blood returning to the systemic circulation.)

* Where CO2 is shunted from the venous to arterial circulation.

Question 13

Which of the following is true regarding the control of alveolar ventilation:

* A lower PO2 increases alveolar ventilation at a given PCO2 (Peripheral chemoreceptors are sensitive to low PO2 and will stimulate an increase in ventilation.)

* A higher pH increases alveolar ventilation at a given PCO2

* PO2 does not influence alveolar ventilation at any level of PCO2

* A higher PO2 increases alveolar ventilation at a given PCO2

Question 14

At rest, a normal breathing rate and tidal volume is approximately:

* 12 breaths/min and 500mL

* 12 breaths/min and 5000mL

* 12 breaths/min and 50mL

* 30 breaths/min and 500mL

Question 15

In a patient with anemia (low iron leading to low hemoglobin in blood), which of the following is true:

* PaO2 will be substantially reduced due to low hemoglobin concentration.

* PaO2 may not be changed as O2 bound to hemoglobin does not contribute to the partial pressure of O2 in blood. (PaO2 reflects the dissolved oxygen in plasma, not the oxygen bound to hemoglobin. While total oxygen content would be reduced in anemia, the partial pressure might remain normal as long as alveolar ventilation and gas exchange are efficient.)

* PaO2 will be substantially increased as O2 cannot bind to hemoglobin so instead it dissolves into plasma.

* PaO2 will be substantially reduced as the ability of plasma to dissolve O2 becomes impaired.

Question 16

Which of the following describes the pleural pressure

* Slightly negative to promote efficient alveolar gas exchange

* Slightly negative to create a suction effect holding the lungs to the chest wall. (The slightly negative intrapleural pressure is crucial for maintaining lung inflation and allowing the lungs to follow the movements of the chest wall.)

* Mostly positive to maintain lung compliance

* Mostly positive to ensure airway stability

Question 17

Pulmonary fibrosis reduces lung compliance. How would this change lung volume measurements?

* Increased vital capacity

* Reduced vital capacity (Reduced compliance means the lungs are stiffer and harder to inflate, leading to smaller lung volumes, including vital capacity.)

* Increased inspiratory reserve volume

* Reduced expiratory flow

Question 18

In the lungs, which of the following statements is true regarding the Bohr and Haldane effects:

* In the lungs, low PaCO₂ and high pH reduce hemoglobin’s affinity for O₂ (Bohr effect), facilitating oxygen offloading. Simultaneously, as hemoglobin becomes deoxygenated, its ability to carry CO₂ is increased, promoting CO₂ loading (Haldane effect).

* In the lungs, low PaCO₂ and high pH enhance hemoglobin’s affinity for O₂ (Bohr effect), facilitating oxygen loading. Simultaneously, as hemoglobin becomes oxygenated, its ability to carry CO₂ is reduced, promoting CO₂ offloading (Haldane effect).

* In the lungs, low PaO₂ and low pH enhance hemoglobin’s affinity for CO₂ (Bohr effect), facilitating CO2 loading. Simultaneously, as hemoglobin becomes loaded with CO2, its ability to carry O₂ is reduced, promoting O₂ offloading (Haldane effect).

* In the lungs, high PaCO₂ and low pH enhance hemoglobin’s affinity for O₂ (Bohr effect), facilitating oxygen loading. Simultaneously, as hemoglobin becomes oxygenated, its ability to carry CO₂ is reduced, promoting CO₂ offloading (Haldane effect).

Question 19

In the medulla, the underlying rhythm of breathing is created by the:

* Lateral respiratory group

* Dorsal respiratory group

* Ventral respiratory group

* Pre-Botzinger complex

Question 20

During periods of intensive exercise, describe the behavior of PaCO2?

* Adaptation of alveolar ventilation maintains a relatively stable PaCO2 during exercise and may decline slightly at higher effort due to hyperventilation. (During exercise, increased CO2 production is met by a proportional increase in ventilation, keeping PaCO2 stable or even slightly lowering it at high intensities due to respiratory compensation for metabolic acidosis.)

* PaCO2 declines during moderate exercise and then increases slightly at maximal effort due to inadequate ventilatory response.

* Increases rapidly due to accumulation of CO2 as a by-product of aerobic respiration

* Hyperventilation leads to PaCO2 being close to zero at maximal effort.

Question 21

Which of the following describes the role of the conducting zone in the respiratory system

* The conducting zone serves as a route for inhaled and exhaled air, warms and humidifies the air, and removes debris and pathogens

* It serves as the principle route of pulmonary blood flow.

* It is the site of gas exchange

* It is the site of the primary respiratory control centre.

Question 22

Which of the following is true:

* Each gram of hemoglobin carries 4mL of O2

* When saturated, each hemoglobin molecule holds four molecules of O2

* When saturated, each hemoglobin molecule holds 16 molecules of O2

* O2 carried on hemoglobin is the major contributor to the partial pressure of O2 in the circulation.

Question 23

Cigarette smoke would induce coughing via:

* stimulation of SARs

* stimulation of peripheral chemoreceptors

* stimulation of RARs

* stimulation of c-fibers (C-fibers are polymodal receptors sensitive to irritants like smoke and often trigger cough.)

Question 24

Which of the following would reduce alveolar gas exchange:

* Increased pressure gradient across alveolar wall

* A reduction in surface area of the alveolar membrane

* Thinning of the alveolar membrane

* An increase in surface area of the alveolar membrane

Question 25

Which of the following might be considered a measure of the efficiency of alveolar gas exchange?

* PaCO2: PaO2 ratio

* PaCO2:VA ratio

* Alveolar to arterial O2 gradient (This gradient reflects the difference between the partial pressure of oxygen in the alveoli and in the arterial blood, indicating how efficiently oxygen is transferred across the alveolar-capillary membrane.)

* arterial to venous O2 gradient

Question 26

Which of the following is not a mechanism of aerosol deposition in the airways

* Hydrostatic settlement

* Diffusion

* Sedimentation

* Impaction (Impaction, sedimentation, and diffusion are the primary mechanisms of aerosol deposition. "Hydrostatic settlement" is not a standard term in this context.)

Question 27

Which of the following structures is primarily responsible for modulating the depth of inspiration during the respiratory cycle:

* Ventral respiratory group

* Vasomotor centre

* Dorsal respiratory group (The DRG primarily controls inspiration, and its activity determines the depth of breathing.)

* Vagus nerve

Question 28

Which of the following is NOT a phase of cough:

* Expiratory phase

* Inspiratory phase

* Isovolumetric phase

* Compression phase (The phases of cough are inspiration, compression, and expiration. "Isovolumetric phase" is not a recognized phase of cough.)

Question 29

During inspiration......

* the diaphragm relaxes to initiate inspiration and contracts for expiration

* the diaphragm contracts to initiate inspiration and then relaxes for expiration

* the diaphragm is mildly active and fully activatess during expiration

* the diaphragm is not active unless required forced inspiration to assist the inspiratory respiratory muscles.

Question 30

Which of the following would increase lung compliance:

* Fibrotic lung disease

* Increased collagen to elastin ratio in the lungs

* Loss of pulmonary surfactant

* Increased elastin to collagen ratio in the lungs (Elastin contributes to the elasticity and stretchability of the lungs, increasing their compliance. Collagen, being stiffer, reduces compliance.)