Ventilation and Perfusion: Matching Airflow and Blood Flow in the Lungs

Question 1

Which mechanism is responsible for the matching of ventilation and blood flow in the lungs?

Accepted Answer

Hypoxic pulmonary vasoconstriction

Answer

Alveolar dead space

Answer

Bronchial collateral ventilation

Answer

Sympathetic innervation of pulmonary vessels

Question 2

Describe the primary function of the respiratory system in the context of ventilation and perfusion:

Accepted Answer

Gas exchange

Answer

Temperature regulation

Answer

Fluid balance

Answer

pH regulation

Question 3

Which of the following lung volumes represents the air remaining in the lungs following a maximal expiration?

Accepted Answer

Residual volume

Answer

Tidal volume

Answer

Functional residual capacity

Answer

Inspiratory capacity

Question 4

Identify the primary factor determining the diffusion of gases across the respiratory membrane:

Accepted Answer

Partial pressure gradient

Answer

Surface area of the membrane

Answer

Thickness of the membrane

Answer

Solubility of the gas

Question 5

Which component is NOT part of the conducting zone of the respiratory system?

Accepted Answer

Bronchioles

Answer

Nose

Answer

Pharynx

Answer

Trachea

Question 6

Which clinical signs may indicate a ventilation-perfusion mismatch causing low blood oxygen levels?

Accepted Answer

Shortness of breath

Accepted Answer

Bluish skin or lips (cyanosis)

Answer

High blood pressure (hypertension)

Answer

Rapid heart rate (tachycardia)

Question 7

Increased pulmonary perfusion in the lungs primarily leads to:

Accepted Answer

Enhanced oxygen uptake

Answer

Reduced carbon dioxide elimination

Answer

Improved ventilation-perfusion ratio

Answer

No significant change in gas exchange

Question 8

How does the presence of dead space in the airways impact ventilation and perfusion?

Accepted Answer

Reduces the efficiency of gas exchange

Answer

Improves the ventilation-perfusion ratio

Answer

Enhances tissue oxygenation

Answer

Has no effect

Question 9

Which of the following factors is NOT involved in the regulation of ventilation?

Accepted Answer

Arterial baroreceptors

Answer

Central chemoreceptors

Answer

Peripheral chemoreceptors

Answer

Lung stretch receptors

Question 10

How does exercise affect ventilation and perfusion in the lungs?

Accepted Answer

Increases both ventilation and perfusion

Answer

Increases ventilation only

Answer

Increases perfusion only

Answer

Decreases both ventilation and perfusion

Question 11

Explain how smoking negatively impacts ventilation and perfusion, outlining the underlying mechanisms and the resulting respiratory consequences.

Accepted Answer

Smoking causes vasoconstriction, reducing pulmonary blood flow and perfusion.

Answer

Smoking increases surfactant production, enhancing lung compliance and ventilation.

Answer

Smoking decreases airway resistance, facilitating increased ventilation.

Answer

Smoking has no significant effects on either ventilation or perfusion.

Question 12

Which of the following factors DOES NOT affect ventilation-perfusion matching?

Accepted Answer

Myocardial contractility

Answer

Gas solubility

Answer

Diffusion distance

Answer

Surface area of the alveoli

Question 13

What is the anatomical structure that allows for the exchange of gases between the alveoli and the blood?

Accepted Answer

Alveolar-capillary membrane

Answer

Bronchi

Answer

Trachea

Answer

Bronchioles

Question 14

What is the term for the partial pressure of carbon dioxide in the blood?

Accepted Answer

PaCO2

Answer

PaO2

Answer

SaO2

Answer

PvO2

Question 15

What is the physiological basis for the use of positive end-expiratory pressure (PEEP) in mechanical ventilation?

Accepted Answer

To maintain lung volume and prevent alveolar collapse

Answer

To reduce pulmonary vascular resistance

Answer

To decrease airway resistance

Answer

To enhance surfactant production

Question 16

What physiological mechanism plays a primary role in determining the distribution of blood flow within the lungs?

Accepted Answer

Pulmonary vascular resistance

Answer

Alveolar ventilation

Answer

Cardiac output

Answer

Tidal volume

Question 17

How is oxygen primarily transported in the blood?

Accepted Answer

Bound to haemoglobin

Answer

Dissolved in plasma

Question 18

Which of the following is a characteristic of emphysema?

Accepted Answer

Destruction of the alveolar walls

Answer

Hypersecretion of mucus

Question 19

What is the diaphragm's role in ventilation?

Accepted Answer

To contract and increase thoracic volume

Answer

To relax and decrease thoracic volume

Question 20

Which of the following is a measure of lung function that indicates the ability to move air in and out of the lungs?

Accepted Answer

Vital capacity

Answer

Residual volume

Question 21

What is the primary function of the respiratory system?

Accepted Answer

To exchange oxygen and carbon dioxide

Answer

To regulate blood pH

Question 22

What is the name of the respiratory centre in the medulla oblongata that controls the rate and depth of breathing?

Accepted Answer

Respiratory rhythm centre

Answer

Apneustic centre

Question 23

What is the primary function of pulmonary surfactant in the lungs?

Accepted Answer

Reduces surface tension, allowing alveoli to expand and contract easily.

Answer

Increases the rate of oxygen diffusion from alveoli to bloodstream.

Answer

Prevents alveoli from collapsing during exhalation.

Answer

Promotes blood clot formation in pulmonary arteries.

Question 24

Where does the primary exchange of gases take place in the respiratory system?

Accepted Answer

Alveoli

Answer

Bronchi

Answer

Pleura

Answer

Trachea

Question 25

How does the structure of the pulmonary microcirculation enhance gas exchange between the alveoli and bloodstream?

Accepted Answer

Thin capillary walls and a large surface area promote diffusion.

Answer

High blood pressure in the capillaries aids filtration.

Answer

Capillary walls contain smooth muscle that controls blood flow and gas exchange.

Answer

The microcirculation is situated in the pleura, maximizing distance from the alveoli.

Question 26

Which of the following factors does NOT influence ventilation-perfusion matching?

Accepted Answer

Body temperature

Answer

Lung volume

Answer

Gravity

Answer

Cardiac output

Question 27

What is the main physiological mechanism responsible for maintaining ventilation-perfusion matching?

Accepted Answer

Hypoxic pulmonary vasoconstriction

Answer

Baroreflex

Answer

Sympathetic innervation

Answer

Diffusion

Question 28

Which of the following measurements is commonly used to assess the efficiency of ventilation-perfusion matching?

Accepted Answer

PaO2/FiO2 ratio

Answer

Heart rate

Answer

Tidal volume

Answer

Respiratory rate

Question 29

What is the main function of the pulmonary circulation?

Accepted Answer

Gas exchange

Answer

Temperature regulation

Answer

Waste removal

Answer

Nutrient delivery

Question 30

Which of the following is NOT a potential consequence of ventilation-perfusion mismatch?

Accepted Answer

Improved gas exchange

Answer

Hypoxemia

Answer

Respiratory acidosis

Answer

Hypercapnia

Question 31

Which of the following factors does NOT impact ventilation-perfusion matching?

Accepted Answer

Gender

Answer

Body position

Answer

Lung volume

Answer

Pulmonary vascular resistance

Question 32

Which of the following is a consequence of significant ventilation-perfusion mismatch?

Accepted Answer

Hypoxemia

Answer

Hypercapnia

Answer

Metabolic acidosis

Answer

Pulmonary edema

Question 33

What is the body's primary adaptive mechanism for chronic ventilation-perfusion mismatch?

Accepted Answer

Hypoxic pulmonary vasoconstriction

Answer

Hyperventilation

Answer

Increased cardiac output

Answer

Increased ventilation

Question 34

What is the primary role of surfactant in facilitating ventilation-perfusion matching?

Accepted Answer

Reduction of surface tension at the air-liquid interface, enhancing lung compliance and stability

Answer

Regulation of pulmonary blood flow

Answer

Facilitation of diffusion of gases across the alveolar-capillary membrane

Question 35

Which of the following techniques is used to assess ventilation-perfusion matching?

Accepted Answer

Multiple inert gas elimination technique (MIGET)

Answer

Spirometry

Answer

Pulse oximetry

Answer

Electrocardiography (ECG)

Question 36

Which of the following is the primary function of the diaphragm in relation to ventilation and perfusion?

Accepted Answer

To separate the thoracic and abdominal cavities, facilitating changes in lung volume during breathing

Answer

To exchange gases between the blood and the air in the alveoli

Answer

To pump blood from the heart to the lungs, ensuring adequate blood supply for gas exchange

Answer

To regulate body temperature by adjusting the rate of respiration

Question 37

What is the name of the process by which oxygen and carbon dioxide move between the alveoli and the blood?

Accepted Answer

Diffusion

Answer

Perfusion, referring to the flow of blood through the pulmonary capillaries

Answer

Ventilation, referring to the movement of air in and out of the lungs

Answer

Respiration, encompassing both ventilation and perfusion

Question 38

What term describes the matching of ventilation and perfusion in the lungs, ensuring efficient gas exchange?

Accepted Answer

Ventilation-perfusion coupling

Answer

Pulmonary circulation, pertaining to the flow of blood through the lungs

Answer

Gas exchange, referring to the actual process of oxygen and carbon dioxide movement

Answer

Bronchial tree, representing the network of airways conducting air to and from the alveoli

Question 39

What is the primary function of the pulmonary arteries in relation to ventilation and perfusion?

Accepted Answer

To carry deoxygenated blood from the heart to the lungs for oxygenation

Answer

To carry oxygenated blood from the lungs to the heart for distribution to the body

Answer

To carry nutrients to the lungs, supporting their metabolic needs

Question 40

What hormone is released in response to low oxygen levels in the blood, stimulating red blood cell production?

Accepted Answer

Erythropoietin

Answer

Thyroid hormone, involved in metabolic regulation

Answer

Adrenaline, a stress hormone with various effects

Question 41

Which of the following is a type of respiratory failure involving a reduced ability of the lungs to expand, affecting ventilation?

Accepted Answer

Restrictive

Answer

Obstructive, involving airflow limitation, primarily affecting ventilation

Answer

Hypoxic, characterized by insufficient oxygen levels in the blood due to impaired gas exchange

Answer

Hypercapnic, characterized by elevated carbon dioxide levels in the blood due to impaired gas exchange

Question 42

What is the main purpose of mechanical ventilation in the clinical setting?

Accepted Answer

To provide respiratory support to patients who are unable to breathe adequately on their own, ensuring adequate gas exchange

Answer

To improve oxygenation, addressing hypoxemia

Answer

To reduce carbon dioxide levels in the blood, specifically targeting hypercapnia