front 1 What are the structures and functions of the conducting and respiratory zones of the lungs? | back 1 Conducting zone: Nose to terminal bronchioles; warms, humidifies, and filters air. Respiratory zone: Respiratory bronchioles to alveoli; site of gas exchange. |
front 2 What structures are involved in gas exchange and how does it occur? | back 2 Structures: Alveoli, alveolar sacs, and capillaries. Mechanism: Diffusion of gases across the alveolar-capillary membrane driven by partial pressure gradients. |
front 3 How is each lung compartmentalized by pleural membranes? | back 3 Visceral pleura: Covers lungs directly. Parietal pleura: Lines thoracic cavity. Pleural space: Between membranes; filled with fluid to reduce friction and maintain negative pressure. |
front 4 What pressure changes occur during inspiration, and how does Boyle’s law explain them? | back 4 Intrapulmonary pressure drops, drawing air in. Boyle’s law: Pressure and volume are inversely related (↑volume = ↓pressure). |
front 5 How do lung compliance and elasticity affect breathing? | back 5 Compliance: Ease of lung expansion. Elasticity: Ability to recoil. High compliance = easier inspiration; high elasticity = more effective expiration. |
front 6 What is pulmonary surfactant and why is it important? | back 6 Surfactant: Lipoprotein that reduces surface tension in alveoli, preventing collapse (especially important in newborns). |
front 7 What muscles are used during quiet inspiration and expiration? | back 7 Inspiration: Diaphragm and external intercostals contract. Quiet expiration: Passive recoil of lungs and diaphragm relaxation. |
front 8 How are forced inspiration and expiration produced? | back 8 Forced inspiration uses: Sternocleidomastoid (neck), scalenes (neck), pectoralis minor (chest), serratus anterior (side ribs), external intercostals (between ribs), diaphragm. How it works: These muscles pull the ribs up and out and push the sternum forward, making the chest bigger so more air can come in. Forced Expiration uses: Internal intercostals (between ribs) and abdominal muscles (abs). How it works: These muscles pull the ribs down and push the diaphragm up, making the chest smaller so air is pushed out quickly. |
front 9 Define tidal volume and vital capacity. | back 9 Tidal volume (TV): Air moved per breath (~500 mL). Vital capacity (VC): Max air exhaled after max inhalation. |
front 10 How is total minute volume calculated and how does exercise affect it? | back 10 Minute volume = TV (tidal volume) × respiratory rate. Increases with exercise due to increased rate and depth. |
front 11 How are VC (vital capacity) and FEV (Forced Expiratory Volume) affected by asthma and pulmonary fibrosis? | back 11 Asthma: ↓FEV (obstructive). Pulmonary fibrosis: ↓VC (restrictive). |
front 12 How is PO₂ (partial pressure of oxygen) of air calculated and how is it affected by altitude, diving, and humidity? | back 12 PO₂ = %O₂ × (atmospheric pressure – water vapor pressure) ↓ with altitude, ↑ with diving, ↓ with high humidity. |
front 13 How is blood PO₂ measured and what is its clinical significance? | back 13 Measured via arterial blood gas (ABG). Reflects lung oxygenation efficiency. |
front 14 Why is systemic arterial PO₂ lower than alveolar PO₂? | back 14 Ventilation-perfusion mismatch and physiological shunting. |
front 15 How is breathing regulated by the CNS? | back 15 Controlled by medulla (rhythm) and pons (modulation). |
front 16 How does ventilation respond to changes in arterial PCO₂? | back 16 Negative feedback: ↑PCO₂ → ↑ventilation to blow off CO₂. |
front 17 How does oxyhemoglobin saturation change with arterial PO₂? | back 17 Sigmoidal curve: Steep rise at low PO₂, plateau at high PO₂. |
front 18 What affects the oxyhemoglobin dissociation curve? | back 18 pH, temperature, CO₂ levels, 2,3-BPG. Right shift = easier oxygen release |
front 19 How do pH and temperature affect oxygen transport? | back 19 ↓pH and ↑temperature = ↓affinity for O₂ (Bohr effect). Occurs during exercise or acidosis. |
front 20 How is CO₂ transported in blood and in what proportions? | back 20 Dissolved (10%), carbaminohemoglobin (20%), bicarbonate (70%). |
front 21 What is the chloride shift and where does it occur? | back 21 Tissues: Cl⁻ enters RBCs as HCO₃⁻ exits. |
front 22 What is the reverse chloride shift and where does it occur? | back 22 Lungs: HCO₃⁻ re-enters RBCs, Cl⁻ exits. |
front 23 How are carbonic acid and bicarbonate formed? | back 23 CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ + HCO₃⁻. Buffer system regulating pH. |
front 24 Define acidosis and alkalosis. What are the two components of acid-base balance? | back 24 Acidosis: pH < 7.35 Alkalosis: pH > 7.45 Components: Respiratory and metabolic. |
front 25 What are the roles of lungs and kidneys in acid-base balance? | back 25 Lungs: Regulate CO₂ (fast). Kidneys: Regulate H⁺ and HCO₃⁻ (slow). |
front 26 What do bicarbonate and carbonic acid do in blood? | back 26 Act as a buffer system to resist pH changes. |
front 27 How do hyperventilation and hypoventilation affect pH? | back 27 Hyperventilation: ↓CO₂ → respiratory alkalosis. Hypoventilation: ↑CO₂ → respiratory acidosis. |
front 28 Why does a person with ketoacidosis hyperventilate? | back 28 To compensate for metabolic acidosis by reducing CO₂ and raising blood pH (e.g., Kussmaul breathing). |