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A 12-year-old boy with a history of asthma experiences shortness of breath and wheezing after
running outside in cold weather. His inhaler (a β2-adrenergic agonist) helps relieve his
symptoms.
Question:How does his inhaler improve his breathing?
A) It stimulates parasympathetic receptors, causing bronchodilation
B) It blocks histamine release from mast cells
C) It activates β2 receptors, relaxing bronchiolar smooth muscle
D) It increases mucus production to trap allergens - Answer -C) It activates β2 receptors, relaxing
bronchiolar smooth muscle - β2-agonists cause bronchodilation by stimulating β2 receptors in
airway smooth muscle, relieving asthma symptoms.
A firefighter is brought to the hospital after exposure to smoke in a burning building. He is
confused, has a headache, and exhibits cherry-red skin coloration.
Question:What is the main reason for his symptoms?
A) Decreased bicarbonate levels
B) Carbon dioxide buildup in the blood
C) Carbon monoxide binding to hemoglobin, preventing oxygen transport
D) Excessive oxygen saturation of hemoglobin - Answer -C) Carbon monoxide binding to
hemoglobin, preventing oxygen transport - CO binds to hemoglobin with high affinity, reducing
oxygen transport and leading to tissue hypoxia.
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,A 35-year-old male arrives at the emergency department after suffering a stab wound to the
right side of his chest. He is experiencing difficulty breathing, and his right lung appears
collapsed on imaging. The physician diagnoses him with a pneumothorax.
What is the most likely reason for his lung collapse?
A) Increased pleural pressure due to air entering the pleural space
B) Excessive surfactant production causing alveolar collapse
C) Increased transpulmonary pressure causing lung hyperinflation
D) A decrease in atmospheric pressure leading to inward lung collapse - Answer -A) Increased
pleural pressure due to air entering the pleural space
A premature infant is diagnosed with neonatal respiratory distress syndrome (NRDS). The
healthcare provider notes that the baby has difficulty expanding the lungs during inspiration.
What is the most likely cause of this condition?
A) Increased alveolar pressure causing air trapping
B) Lack of surfactant leading to increased alveolar surface tension
C) Increased pleural pressure making lung expansion difficult
D) Excessive elastic recoil preventing inhalation - Answer -B) Lack of surfactant leading to
increased alveolar surface tension
A weightlifter is performing a heavy deadlift and is observed holding his breath and straining. He
suddenly feels lightheaded and has a brief moment of dizziness.
What intrathoracic pressure change is most likely responsible for this effect?
A) Decreased pleural pressure due to increased lung volume
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,B) Increased intrathoracic pressure reducing venous return to the heart
C) Increased alveolar pressure promoting better oxygen exchange
D) Decreased transpulmonary pressure causing lung overexpansion - Answer -B) Increased
intrathoracic pressure reducing venous return to the heart
A 65-year-old male with chronic obstructive pulmonary disease (COPD) has difficulty exhaling
and often uses pursed-lip breathing to improve airflow.
What intrathoracic pressure change is most likely responsible for his difficulty exhaling?
A) Increased pleural pressure compressing the alveoli
B) Increased alveolar pressure due to air trapping
C) Decreased transpulmonary pressure preventing lung collapse
D) Decreased pleural pressure leading to excessive lung expansion - Answer -B) Increased
alveolar pressure due to air trapping
A medical student is asked to explain the process of air entry during normal breathing.
Which of the following best describes the mechanism of inspiration?
A) Alveolar pressure becomes more positive, forcing air into the lungs
B) Pleural pressure becomes more positive, reducing lung expansion
C) Alveolar pressure decreases below atmospheric pressure, drawing air in
D) Pleural pressure becomes more positive, increasing lung compliance - Answer -C) Alveolar
pressure decreases below atmospheric pressure, drawing air in
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, An 82-year-old woman presents to the clinic complaining of shortness of breath during mild
exertion. She denies any history of smoking or chronic respiratory disease. Pulmonary function
tests reveal reduced lung compliance and a decreased diffusing capacity for oxygen.
Which of the following best explains her reduced gas exchange efficiency?
A) Increased alveolar surface area due to enhanced lung elasticity
B) Decreased pulmonary capillary density leading to impaired oxygen diffusion
C) Increased respiratory muscle strength allowing for enhanced ventilation
D) Increased lung compliance due to excessive surfactant production - Answer -B) Decreased
pulmonary capillary density leading to impaired oxygen diffusion
A 78-year-old male is undergoing pulmonary function testing. The physician notes that his chest
wall expansion is limited, and his rib cage appears stiff on imaging.
What is the most likely cause of his reduced chest expansion?
A) Increased flexibility of the costovertebral joints
B) Decreased calcification of the rib cartilage
C) Age-related stiffness of the thoracic cage and reduced muscle strength
D) Increased diaphragmatic function enhancing lung expansion - Answer -C) Age-related
stiffness of the thoracic cage and reduced muscle strength
A 75-year-old former marathon runner visits his physician for a routine checkup. Pulmonary
function tests show an increase in residual lung volume and decreased elastic recoil of the
lungs.
What is the most likely cause of the increased residual lung volume?
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