Ventilation • Respiration • Perfusion
Define ventilation, external respiration, internal respiration, and perfusion—how do they link? [Slides: Lecture 3; Tutorial 3]
Ventilation = air in/out alveoli; external = lung gas exchange; internal = tissue gas exchange; perfusion = pulmonary blood flow. Oxygenation requires alignment (V/Q match)
Dalton’s law in one line and why it matters for diffusion. [Slides: Lecture 15–16; Tutorial 10–11]
Each gas has its own partial pressure; diffusion follows partial pressure gradients across the membrane.
Most O₂ is carried in blood how? [Slides: Lecture 25]
Bound to haemoglobin.
Primary brainstem site for basic respiratory rhythm + one key peripheral chemoreceptor location. [Slides: Lecture 32–34]
Medulla; carotid bodies (also aortic bodies).
List the three main layers and explain why thickness matters for gas exchange. [Slides: Lecture 18–19]
Alveolar epithelium (type I) → fused basement membrane → capillary endothelium; ↑thickness (oedema/fibrosis) ↓diffusion → hypoxaemia.
What does V/Q mismatch mean? Give one example. [Slides: Lecture 22]
V ≠ Q. Low V/Q (pneumonia); high V/Q (PE → dead space).
Henry’s law explains why ↑FiO₂ can ↑PaO₂. State how. [Slides: Lecture 13–14; Tutorial 12, 15–16]
Dissolved gas ∝ partial pressure → giving O₂ increases dissolved O₂ and drives diffusion.
Bohr effect—what shifts the O₂–Hb curve right, and what’s the tissue effect? [Slides: Lecture 25; Tutorial 13]
↑CO₂/↑H⁺(↓pH), ↑Temp, ↑2,3‑BPG → right shift → easier O₂ unloading at tissues.
In obstructive disease, what happens to FEV₁/FVC and why? [Slides: Lecture 10 & 35; Tutorial 18]
Ratio ↓ due to airway narrowing/air trapping → reduced rapid expiratory flow.
Name two physical factors that increase work of breathing and why. [Slides: Lecture 8]
↑Airway resistance (bronchoconstriction/mucus); ↓compliance (fibrosis/oedema) → larger pressure change needed for same VT.
Two structural features of the respiratory membrane that promote rapid diffusion. [Slides: Lecture 18–19; Tutorial 5]
Extremely thin barrier (type I alveolar cell + fused basement membrane + capillary endothelium), huge surface area, dense capillary network.
Most CO₂ travels as what, and where is it formed? [Slides: Lecture 28; Tutorial 14]
Bicarbonate (HCO₃⁻), formed in RBCs via carbonic anhydrase; Haldane effect supports CO₂ carriage
During an asthma attack, list two bedside manifestations you’d expect. [Slides: Lecture 43–44; Tutorial 20–21]
Wheeze, prolonged expiration, cough, chest tightness, accessory muscle use, tachypnoea; severe: silent chest/cyanosis/↓LOC.