Respiratory System — Multiple Choice

1. Which process describes gas exchange between alveoli and pulmonary blood?

A. Ventilation

B. Internal respiration

C. External respiration

D. Oxygenation

Answer: C. External respiration

2. What structure serves as the primary site of gas exchange in the lungs?

A. Bronchioles

B. Alveoli

C. Trachea

D. Pharynx

Answer: B. Alveoli

3. Which structure prevents food from entering the trachea during swallowing?

A. Glottis

B. Soft palate

C. Epiglottis

D. Pharynx

Answer: C. Epiglottis

4. What does Boyle’s law state?

A. Pressure and temperature are directly proportional

B. Volume and temperature are inversely related

C. Pressure varies inversely with volume at constant temperature

D. Gas solubility increases with temperature

Answer: C. Pressure varies inversely with volume at constant temperature

5. Which pressure keeps the lungs inflated under normal conditions?

A. Intrapulmonary pressure

B. Atmospheric pressure

C. Intrapleural pressure

D. Transpulmonary pressure

Answer: D. Transpulmonary pressure

6. Which hormone or signal dilates bronchioles during an asthma attack?

A. Histamine

B. Acetylcholine

C. Epinephrine

D. Serotonin

Answer: C. Epinephrine

7. Which cells produce surfactant in the alveoli?

A. Type I alveolar cells

B. Type II alveolar cells

C. Macrophages

D. Ciliated epithelial cells

Answer: B. Type II alveolar cells

8. What happens to air pressure inside the lungs during inspiration?

A. It rises above atmospheric pressure

B. It stays the same

C. It drops below atmospheric pressure

D. It equals intrapleural pressure

Answer: C. It drops below atmospheric pressure

9. Which condition results from a loss of negative pressure in the pleural cavity?

A. Asthma

B. Pulmonary fibrosis

C. Lung collapse

D. Hyperventilation

Answer: C. Lung collapse

10. What is the primary chemical stimulus for breathing?

A. Low oxygen

B. High carbon dioxide

C. Low blood pH

D. High nitrogen

Answer: B. High carbon dioxide

1. What is the function of the epiglottis?

A. Amplifies voice resonance

B. Produces surfactant

C. Prevents food from entering the larynx

D. Connects alveoli to capillaries

Answer: C. Prevents food from entering the larynx

2. Which respiratory structure is responsible for voice production?

A. Pharynx

B. Trachea

C. Larynx

D. Epiglottis

Answer: C. Larynx

3. What determines the pitch of your voice?

A. Length and tension of the vocal cords

B. Amount of air pressure in lungs

C. Shape of the nasal cavity

D. Thickness of alveolar walls

Answer: A. Length and tension of the vocal cords

4. Which of the following is a role of the nasal conchae?

A. Equalize pressure in lungs

B. Produce surfactant

C. Filter, warm, and moisten air

D. Absorb CO₂

Answer: C. Filter, warm, and moisten air

5. What is the major function of surfactant?

A. Stimulate coughing

B. Increase mucus production

C. Reduce surface tension in alveoli

D. Decrease oxygen diffusion

Answer: C. Reduce surface tension in alveoli

6. What happens if type II alveolar cells are deficient in newborns?

A. Hyperventilation

B. Infant respiratory distress syndrome

C. Lung fibrosis

D. Asthma

Answer: B. Infant respiratory distress syndrome

7. What is anatomical dead space?

A. Area of collapsed alveoli

B. Volume of air that doesn’t participate in gas exchange

C. Area of lungs with maximum perfusion

D. Residual volume in alveoli

Answer: B. Volume of air that doesn’t participate in gas exchange

8. Which pressure is always negative and helps prevent lung collapse?

A. Atmospheric pressure

B. Intrapulmonary pressure

C. Intrapleural pressure

D. Alveolar pressure

Answer: C. Intrapleural pressure

9. What are the conducting zone structures responsible for?

A. Gas exchange

B. Oxygen transport

C. Air filtration and movement to respiratory zone

D. Surfactant production

Answer: C. Air filtration and movement to respiratory zone

10. What structure connects the respiratory and digestive systems?

A. Trachea

B. Bronchi

C. Larynx

D. Pharynx

Answer: D. Pharynx

1. What are the two layers of pleura surrounding the lungs?

A. Thoracic and pericardial

B. Visceral and parietal

C. Mucosal and serosal

D. Bronchial and alveolar

Answer: B. Visceral and parietal

2. What is the primary function of the trachealis muscle?

A. Produces mucus

B. Assists in phonation

C. Controls diameter of trachea during coughing

D. Filters pathogens

Answer: C. Controls diameter of trachea during coughing

3. What volume of air remains in the lungs after a forced exhalation?

A. Tidal volume

B. Residual volume

C. Inspiratory reserve volume

D. Functional capacity

Answer: B. Residual volume

4. What is total lung capacity (TLC)?

A. Volume of air during quiet breathing

B. Maximum amount of air lungs can hold

C. Gas exchanged in a single breath

D. Air that remains in alveoli after exhalation

Answer: B. Maximum amount of air lungs can hold

5. What effect does fibrosis have on lung compliance?

A. Increases compliance

B. No effect

C. Decreases compliance

D. Eliminates compliance entirely

Answer: C. Decreases compliance

6. What is the function of the nasal mucosa?

A. Humidify and filter air

B. Perform gas exchange

C. Move food into esophagus

D. Stimulate breathing

Answer: A. Humidify and filter air

7. Why do bronchioles have more smooth muscle than bronchi?

A. To produce mucus

B. To aid in oxygen diffusion

C. To control airflow resistance

D. To increase lung compliance

Answer: C. To control airflow resistance

8. Which of the following contributes to voice loudness?

A. Size of alveoli

B. Air pressure from lungs

C. Number of vocal folds

D. Tension of epiglottis

Answer: B. Air pressure from lungs

9. What structure helps equalize air pressure throughout the lungs?

A. Bronchioles

B. Alveolar pores

C. Cilia

D. Capillaries

Answer: B. Alveolar pores

10. What is the opening between the vocal cords called?

A. Glottis

B. Larynx

C. Pharynx

D. Uvula

Answer: A. Glottis

Respiratory System — Multiple Choice Questions (Set 4)

1. Which respiratory volume increases significantly in obstructive disorders like asthma?

A. Residual volume

B. Inspiratory reserve volume

C. Tidal volume

D. Vital capacity

Answer: A. Residual volume

2. What is the function of type I alveolar cells?

A. Secrete surfactant

B. Produce mucus

C. Form the thin wall for gas exchange

D. Trap dust particles

Answer: C. Form the thin wall for gas exchange

3. What part of the brain controls rhythmic breathing?

A. Cerebellum

B. Frontal lobe

C. Medulla oblongata

D. Hippocampus

Answer: C. Medulla oblongata

4. Which structure allows equalization of pressure in the middle ear?

A. Alveolar duct

B. Vestibular fold

C. Pharyngotympanic tube

D. Cricoid cartilage

Answer: C. Pharyngotympanic tube

5. What happens to pH during hypoventilation?

A. Increases (alkalosis)

B. Decreases (acidosis)

C. No change

D. Becomes neutral

Answer: B. Decreases (acidosis)

6. Why does gas exchange become impaired when respiratory membranes thicken?

A. Surface area increases

B. Diffusion slows down

C. Ventilation increases

D. Capillary blood flow stops

Answer: B. Diffusion slows down

7. What causes the PO₂ to decrease from atmospheric air (160 mm Hg) to alveolar air (104 mm Hg)?

A. CO₂ replacement

B. Humidification and mixing with residual air

C. Nitrogen exchange

D. Rapid blood flow

Answer: B. Humidification and mixing with residual air

8. What is cyanosis a sign of?

A. High oxygen levels

B. Hypoxia

C. Bronchial obstruction

D. Lung overinflation

Answer: B. Hypoxia

9. How is most carbon dioxide transported in the blood?

A. Bound to iron in hemoglobin

B. Dissolved in plasma

C. As carbonic acid

D. As bicarbonate ions

Answer: D. As bicarbonate ions

10. What is the Bohr effect?

A. O₂ increases CO₂ binding

B. CO₂ and low pH promote O₂ release from hemoglobin

C. High oxygen blocks CO₂ transport

D. Hemoglobin binds O₂ more tightly at low temperatures

Answer: B. CO₂ and low pH promote O₂ release from hemoglobin

1. What role does hemoglobin play in oxygen transport?

A. Acts as a surfactant

B. Dissolves oxygen directly in plasma

C. Binds to oxygen for transport in red blood cells

D. Neutralizes CO₂ in tissues

Answer: C. Binds to oxygen for transport in red blood cells

2. What happens to hemoglobin’s affinity for oxygen as more O₂ binds?

A. It decreases

B. It stays the same

C. It increases

D. It becomes irreversible

Answer: C. It increases

3. What causes the oxygen-hemoglobin dissociation curve to shift right?

A. Cold temperature

B. High pH

C. High CO₂, low pH, or increased temperature

D. Decreased CO₂ and low temperature

Answer: C. High CO₂, low pH, or increased temperature

4. Which factor most strongly stimulates breathing under normal conditions?

A. Low oxygen

B. High nitrogen

C. Increased carbon dioxide

D. Blood glucose

Answer: C. Increased carbon dioxide

5. What is the Haldane effect?

A. Low CO₂ increases hemoglobin binding

B. High O₂ promotes CO₂ release from hemoglobin

C. High pH decreases CO₂ transport

D. More O₂ increases CO₂ solubility

Answer: B. High O₂ promotes CO₂ release from hemoglobin

6. What is the most abundant gas in atmospheric air?

A. Oxygen

B. Carbon dioxide

C. Nitrogen

D. Hydrogen

Answer: C. Nitrogen

7. What law explains why gases diffuse down their pressure gradients?

A. Henry’s Law

B. Boyle’s Law

C. Dalton’s Law

D. LaPlace’s Law

Answer: C. Dalton’s Law

8. What is minute ventilation?

A. Air that remains after maximal expiration

B. Volume of air exchanged per breath

C. Total air movement per minute (TV × respiratory rate)

D. Gas exchanged in the alveoli only

Answer: C. Total air movement per minute (TV × respiratory rate)

9. What is the main driver for oxygen unloading at tissues?

A. Low CO₂

B. High PO₂

C. Low PO₂ in tissues

D. High blood pH

Answer: C. Low PO₂ in tissues

10. Which of the following is most soluble in plasma?

A. Nitrogen

B. Oxygen

C. Carbon dioxide

D. Hydrogen

Answer: C. Carbon dioxide

1. Which law explains why CO₂ dissolves more easily in blood than O₂?

A. Dalton’s Law

B. Henry’s Law

C. Boyle’s Law

D. Fick’s Law

Answer: B. Henry’s Law

2. Which of the following happens during quiet expiration?

A. Diaphragm contracts

B. Intrapulmonary pressure drops

C. Muscles contract forcefully

D. Muscles relax and lungs recoil

Answer: D. Muscles relax and lungs recoil

3. What do chemoreceptors in the aortic and carotid bodies detect?

A. Body temperature

B. pH, CO₂, and O₂ levels in the blood

C. Air pressure in lungs

D. Stretch of alveoli

Answer: B. pH, CO₂, and O₂ levels in the blood

4. What is the main function of the respiratory membrane?

A. Prevent pathogens from entering lungs

B. Allow gas exchange between air and blood

C. Absorb nutrients

D. Filter blood

Answer: B. Allow gas exchange between air and blood

5. What is the effect of increasing respiratory rate on CO₂ levels?

A. Increases CO₂ retention

B. Decreases CO₂ levels

C. Has no effect

D. Increases CO₂ solubility

Answer: B. Decreases CO₂ levels

6. Which muscle is most responsible for quiet inspiration?

A. Internal intercostals

B. Sternocleidomastoid

C. Diaphragm

D. Rectus abdominis

Answer: C. Diaphragm

7. What happens when airway resistance increases?

A. Ventilation becomes easier

B. Gas exchange improves

C. Breathing becomes more difficult

D. Lung compliance increases

Answer: C. Breathing becomes more difficult

8. Where is the respiratory control center located?

A. Hypothalamus

B. Pons and medulla

C. Cerebellum

D. Spinal cord

Answer: B. Pons and medulla

9. What structure divides the nasal cavity and helps direct airflow?

A. Septum

B. Uvula

C. Palate

D. Conchae

Answer: A. Septum

10. What causes alveolar collapse in premature infants?

A. Excess mucus

B. Lack of macrophages

C. Absence of surfactant

D. Hyperinflation

Answer: C. Absence of surfactant

Respiratory System — Multiple Choice Questions (Set 7)

1. What is internal respiration?

A. Breathing air into the lungs

B. Gas exchange between blood and tissue cells

C. Gas exchange between lungs and atmosphere

D. O₂ binding to hemoglobin

Answer: B. Gas exchange between blood and tissue cells

2. What causes airflow into the lungs during inspiration?

A. Pressure in lungs exceeds atmospheric pressure

B. Pressure in lungs drops below atmospheric pressure

C. Diaphragm relaxes

D. Air moves due to increased resistance

Answer: B. Pressure in lungs drops below atmospheric pressure

3. What is tidal volume?

A. Air that remains in lungs after full expiration

B. Total lung capacity

C. Air exchanged during normal breathing

D. Air exhaled during forced expiration

Answer: C. Air exchanged during normal breathing

4. What is the role of alveolar macrophages?

A. Secrete surfactant

B. Perform gas exchange

C. Clean debris and pathogens from alveoli

D. Control bronchial diameter

Answer: C. Clean debris and pathogens from alveoli

5. What increases during exercise to meet oxygen demands?

A. Lung compliance

B. Residual volume

C. Respiratory rate and tidal volume

D. Surface tension

Answer: C. Respiratory rate and tidal volume

6. Why does high altitude trigger increased red blood cell production?

A. Increased nitrogen uptake

B. Decreased oxygen levels stimulate erythropoietin

C. Carbon dioxide causes hyperventilation

D. Pressure difference increases oxygen solubility

Answer: B. Decreased oxygen levels stimulate erythropoietin

7. How is most oxygen transported in the blood?

A. Bound to albumin

B. Dissolved in plasma

C. Bound to hemoglobin

D. Converted to CO₂

Answer: C. Bound to hemoglobin

8. Which gas has the greatest partial pressure in atmospheric air?

A. O₂

B. CO₂

C. N₂

D. H₂O vapor

Answer: C. N₂

9. Which part of the lung receives its own bronchus, artery, and vein?

A. Alveolus

B. Lobe

C. Bronchopulmonary segment

D. Hilum

Answer: C. Bronchopulmonary segment

10. What is the primary site of resistance in the airway?

A. Trachea

B. Bronchi

C. Bronchioles

D. Alveoli

Answer: C. Bronchioles