Structure
Q: What are the two main functional zones of the respiratory system?
A: The conducting zone (nose → terminal bronchioles) that moves and conditions air, and the respiratory zone (respiratory bronchioles → alveoli) where gas exchange occurs.
Q: What is dyspnea?
A: A subjective sensation of uncomfortable or difficult breathing.
Q: What is Cheyne-Stokes respiration?
A: A pattern of alternating periods of deep, rapid breathing and apnea, often seen in heart failure, brain injury, or end-of-life.
Q: Why is COPD considered only partially reversible, unlike asthma?
A: In COPD there is permanent structural damage—such as destruction of alveolar walls (emphysema) and chronic airway remodeling with mucus gland enlargement (chronic bronchitis)—so airflow limitation persists even after bronchodilators and anti‑inflammatory treatment, making it only partially reversible.
Q: What is the primary function of the alveoli?
A: To provide a large, thin, moist surface for gas exchange between air and pulmonary capillary blood.
Q: What is paroxysmal nocturnal dyspnea (PND)?
A: Sudden episodes of severe shortness of breath at night that wake the person from sleep, often associated with heart failure.
Q: Why does Cheyne-Stokes breathing occur?
A: Because of delayed response of the respiratory center to changes in blood CO₂, leading to cyclical over- and under-ventilation.
Q: Briefly differentiate chronic bronchitis from emphysema.
A: Chronic bronchitis: chronic productive cough and mucus hypersecretion; emphysema: permanent enlargement of airspaces and destruction of alveolar walls with loss of elastic recoil.
Q: What is surfactant and what is its main role?
A: A phospholipid-rich substance produced by type II alveolar cells that reduces surface tension, preventing alveolar collapse at end-expiration.
Q: What is acute cough typically associated with?
A: Short-term respiratory infections such as colds, acute bronchitis, or pneumonia.
Q: What is apnea, and why is it clinically significant?
A: Apnea is a complete absence of breathing for a period of time; it is clinically significant because prolonged apnea leads to hypoxemia, hypercapnia, and can result in loss of consciousness, brain injury, or death if not corrected.
Q: How is dyspnea different from tachypnea?
A: Dyspnea is the subjective feeling of difficult breathing; tachypnea is an objectively increased respiratory rate, which may or may not be perceived as distress.
Q: What is a pulmonary embolism?
A: An obstruction of the pulmonary artery or its branches by a thrombus (usually from DVT), fat, air, or other material.
Q: What is the function of the pleural space and pleural fluid?
A: It provides lubrication to reduce friction during breathing and creates a negative pressure that helps keep the lungs expanded.
Q: What defines a chronic cough?
A: A cough lasting more than 3 weeks (often more than 8 weeks in adults), frequently due to chronic bronchitis, asthma, GERD, or postnasal drip.
Q: What is digital clubbing?
A: A bulbous enlargement of the distal fingers or toes, with increased nail curvature and spongy nail beds.
Q: What is acute cough most often caused by?
A: Viral upper respiratory infections, acute bronchitis, allergic reactions, or pneumonia.
Q: What is the function of the diaphragm in respiration?
A: The diaphragm is the primary muscle of inspiration; when it contracts, it flattens and moves downward, increasing thoracic volume and creating negative pressure that draws air into the lungs.
Q: What is Kussmaul breathing and when is it usually seen?
A: Deep, rapid, labored breathing usually seen in metabolic acidosis, especially diabetic ketoacidosis.
Q: What does digital clubbing usually indicate?
A: Chronic hypoxemia, commonly due to chronic lung diseases, cyanotic heart disease, or other long-standing cardiopulmonary disorders.
Q: Why is it important to recognize paroxysmal nocturnal dyspnea (PND)?
A: Because it is a key sign of left-sided heart failure and pulmonary congestion and may require urgent evaluation and treatment.