A. Trachea
B. Main bronchi
C. Alveolar duct
D. Pharynx
# The partial pressure of oxygen (pO2) in the alveoli is approximately:
A. 40 mm Hg
B. 160 mm Hg
C. 104 mm Hg
D. 95 mm Hg
# The volume of air that can be inspired forcefully after a normal inspiration is called:
A. Residual Volume (RV)
B. Tidal Volume (TV)
C. Expiratory Reserve Volume (ERV)
D. Inspiratory Reserve Volume (IRV)
# Which of the following would cause the oxy-hemoglobin dissociation curve to shift to the right?
A. Decreased pCO2
B. Increased pH
C. Increased levels of 2,3-DPG
D. Decreased body temperature
# The respiratory center in the brain is stimulated primarily by:
A. High concentration of carbon dioxide in the blood
B. High concentration of oxygen in the blood
C. Low concentration of oxygen in the blood
D. Low concentration of carbon dioxide in the blood
# The serous membrane covering the surface of the lungs is called the:
A. Parietal pleura
B. Mediastinum
C. Visceral pleura
D. Pericardium
# What is the primary muscle of quiet inspiration?
A. Internal intercostals
B. Diaphragm
C. Abdominal muscles
D. External intercostals
# The majority of carbon dioxide is transported in the blood as:
A. Carbaminohemoglobin
B. Dissolved CO₂ in plasma
C. Bicarbonate ions (HCO₃⁻)
D. Carbonic acid (H₂CO₃)
# In restrictive lung diseases like fibrosis, which of the following is typically decreased the most?
A. Tidal Volume (TV)
B. Vital Capacity (VC)
C. Forced Expiratory Volume in 1 second (FEV1)
D. Residual Volume (RV)
# The 'Hering-Breuer reflex' is primarily a response to:
A. High levels of CO₂
B. Over-inflation of the lungs
C. Low levels of O₂
D. Irritants in the airway
# What is the role of surfactant in the alveoli?
A. To increase the surface tension of alveolar fluid
B. To transport oxygen across the alveolar membrane
C. To warm the inspired air
D. To reduce the surface tension of alveolar fluid
# The Bohr effect describes the phenomenon where:
A. An increase in CO₂ and H⁺ ions causes hemoglobin to release oxygen more readily.
B. A decrease in temperature increases hemoglobin's affinity for oxygen.
C. An increase in O₂ causes hemoglobin to release CO₂ more readily.
D. An increase in CO₂ causes hemoglobin to bind more oxygen.
# The structure that prevents food from entering the trachea during swallowing is the:
A. Soft palate
B. Glottis
C. Uvula
D. Epiglottis
# Which of the following lung volumes or capacities cannot be measured by simple spirometry?
A. Vital Capacity (VC)
B. Functional Residual Capacity (FRC)
C. Inspiratory Capacity (IC)
D. Expiratory Reserve Volume (ERV)
# The pneumotaxic center is located in the:
A. Cerebellum
B. Hypothalamus
C. Medulla oblongata
D. Pons
# Dead space air is the volume of air that:
A. Remains in the lungs after maximal expiration.
B. Is exchanged during a normal breath.
C. Occupies the conducting airways and does not participate in gas exchange.
D. Can be forcefully inhaled after a normal inspiration.
# Carbonic anhydrase, an enzyme crucial for CO₂ transport, is found in high concentrations in:
A. Lung surfactant
B. Plasma
C. Alveolar macrophages
D. Red blood cells
# Which of the following conditions is characterized by destruction of alveolar walls and loss of elastic recoil?
A. Acute bronchitis
B. Pulmonary fibrosis
C. Emphysema
D. Asthma
# The 'chloride shift' (Hamburger's phenomenon) refers to the movement of chloride ions:
A. From the blood into the interstitial fluid
B. From the red blood cell into the plasma
C. From the alveoli into the blood
D. From the plasma into the red blood cell
# Hypoxia caused by cyanide poisoning is an example of:
A. Histotoxic hypoxia
B. Stagnant (ischemic) hypoxia
C. Hypoxic hypoxia
D. Anemic hypoxia
# The total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual gases. This is stated by:
A. Henry's Law
B. Dalton's Law
C. Charles's Law
D. Boyle's Law
# The vocal cords are located within the:
A. Trachea
B. Pharynx
C. Esophagus
D. Larynx
# A patient's blood gas analysis shows pH 7.25, pCO₂ 60 mm Hg, and HCO₃⁻ 26 mEq/L. This indicates:
A. Metabolic alkalosis
B. Respiratory alkalosis
C. Metabolic acidosis
D. Respiratory acidosis
# The rate of diffusion of a gas across the respiratory membrane is inversely proportional to the:
A. Partial pressure gradient of the gas
B. Thickness of the membrane
C. Surface area of the membrane
D. Solubility of the gas
# During forceful expiration, which muscles are primarily contracted?
A. Abdominal muscles and internal intercostals
B. Sternocleidomastoid and scalenes
C. Diaphragm and external intercostals
D. Pectoralis minor and serratus anterior
# The Haldane effect facilitates the transport of:
A. Bicarbonate into the red blood cells
B. Carbon dioxide in the blood
C. Nitrogen during diving
D. Oxygen in the lungs
# A characteristic feature of asthma is:
A. Irreversible airflow obstruction
B. Bronchial hyperresponsiveness
C. Decreased lung compliance
D. Destruction of alveolar septa
# The apneustic center in the pons acts to:
A. Stimulate forceful expiration
B. Inhibit inspiration
C. Set the basic rhythm of breathing
D. Prolong inspiration
# Which of these combinations represents the Inspiratory Capacity (IC)?
A. Expiratory Reserve Volume + Residual Volume (ERV + RV)
B. Vital Capacity + Residual Volume (VC + RV)
C. Tidal Volume + Inspiratory Reserve Volume (TV + IRV)
D. Inspiratory Reserve Volume + Expiratory Reserve Volume (IRV + ERV)
# Peripheral chemoreceptors (carotid and aortic bodies) are most sensitive to changes in:
A. Arterial pO₂
B. Arterial pH
C. Venous pO₂
D. Arterial pCO₂
# In a person at high altitude for two weeks, which of the following changes would be expected?
A. Respiratory alkalosis with no renal compensation
B. Decreased heart rate
C. Increased concentration of 2,3-DPG in red blood cells
D. Decreased production of erythropoietin
# The right lung is different from the left lung in that it has:
A. Three lobes
B. A cardiac notch
C. Two lobes
D. A single fissure
# Which type of cell is responsible for producing pulmonary surfactant?
A. Type II pneumocytes
B. Type I pneumocytes
C. Alveolar macrophages
D. Goblet cells
# The FEV1/FVC ratio is characteristically decreased in which condition?
A. Restrictive lung disease (e.g., pulmonary fibrosis)
B. Kyphoscoliosis
C. Obstructive lung disease (e.g., COPD)
D. Pulmonary edema
# What is the primary factor that determines the direction of gas movement across the respiratory membrane?
A. The temperature of the blood
B. The concentration of hemoglobin
C. The speed of blood flow
D. The difference in partial pressures of the gas
# The C-shaped cartilaginous rings of the trachea are open posteriorly to allow for:
A. Expansion of the esophagus during swallowing
B. Attachment of the vocal cords
C. Movement of the neck
D. Expansion of the trachea during inhalation
# Dyspnea is the medical term for:
A. A bluish discoloration of the skin
B. A subjective sensation of difficult or uncomfortable breathing
C. A rapid respiratory rate
D. Cessation of breathing
# Atelectasis refers to:
A. Collapse or incomplete expansion of the lung or a portion of the lung
B. Inflammation of the pleura
C. Air in the pleural space
D. Fluid in the pleural space
# The most powerful respiratory stimulus for a healthy person breathing room air is:
A. Arterial pCO₂
B. Arterial pO₂
C. Venous pCO₂
D. Arterial H+
# What is the approximate value of intrapleural pressure during quiet inspiration?
A. +3 cm H₂O
B. -5 to -8 cm H₂O
C. 0 cm H₂O (equal to atmospheric)
D. -2 cm H₂O
# Vital Capacity (VC) is the sum of:
A. Inspiratory Reserve Volume + Expiratory Reserve Volume + Tidal Volume
B. Functional Residual Capacity + Inspiratory Reserve Volume
C. Tidal Volume + Inspiratory Reserve Volume + Residual Volume
D. Total Lung Capacity - Functional Residual Capacity
# The trachealis muscle is located on the posterior aspect of the trachea. Its contraction leads to:
A. An increase in the diameter of the trachea to allow more airflow.
B. A decrease in the diameter of the trachea, which assists in coughing.
C. Lengthening of the trachea.
D. Prevention of tracheal collapse.
# Which of the following has the highest affinity for hemoglobin?
A. Carbon Monoxide (CO)
B. Oxygen (O2)
C. Carbon Dioxide (CO2)
D. Hydrogen ion (H+)
# The relationship between pressure and volume of a gas at constant temperature is described by:
A. Henry's Law
B. Dalton's Law
C. Boyle's Law
D. Laplace's Law
# Which portion of the pharynx serves only as an air passageway?
A. Nasopharynx
B. Oropharynx
C. Laryngopharynx
D. All parts of the pharynx serve both functions.
# The driving pressure for airflow during breathing is the pressure difference between the:
A. Intrapleural space and the intrathoracic space
B. Atmosphere and the alveoli
C. Alveoli and the intrapleural space
D. Atmosphere and the intrapleural space
# Cheyne-Stokes respiration is a pattern of breathing characterized by:
A. Complete absence of breathing
B. Periods of apnea alternating with periods of hyperventilation
C. Irregular breathing with no discernible pattern
D. Rapid, deep breathing (hyperpnea)
# The amount of O2 that can be transported in blood is primarily determined by:
A. The concentration of hemoglobin
B. The pCO2 of the blood
C. The amount of dissolved O2 in plasma
D. The respiratory rate
# Which of these is considered an accessory muscle of inspiration?
A. Scalene muscles
B. Internal intercostals
C. Diaphragm
D. Rectus abdominis
# The lingula is a tongue-like projection from which lobe of the lung?
A. Middle lobe of the right lung
B. Inferior lobe of the left lung
C. Superior lobe of the right lung
D. Superior lobe of the left lung
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