Mechanics of ventilation How the lung is supported and moved

Pneumothorax of right lung

Rotation axis ribs

Static recoil Interpleural pressure Air flow inspexsp Interpleural pressure Tidal volume

P=T/r ↑r ↓T P = P ↓CL↓CL Dipalmitol fosfatidil cholin + protein

Alveoli are larger at the apex (upper panel) than base (lower)

∆V ∆P C = ∆V / ∆P

∆P ∆V. R=∆P / ∆V.

Number of airways increases rapidly with generation

Mechanism of dynamic compression

Work done on the lung during breathing

Transport of gas from alveoli to blood

Gas Membrane blood 0.5 μm

Very thin blood-gas barrier

Limitation by perfusion Limitation by diffusion

Respiration at the limit: surviving on the summit of Mt Everest

Highest altitudes attained in the last century

Maximum oxygen uptake at increasing altitudes

Climbers Ranked by their Hypoxic Ventilatory Response

Alveolar Pco 2 at Extreme Altitudes

Pulmonary Gas Exchange on the Everest Summit

O 2 Dissociation Curves in High-Altitude Mammals

Decrease of barometric pressure with altitude

Climber on the Everest Summit

Polycythemia at 4600 m altitude Hemoglobin concentration 19.8 g/dl Arterial PO 2 45 mm Hg O 2 saturation 81% O 2 concentration 22.4 ml/dl

D LO2 = V O2 / P AO2 P c O2 D LCO = V CO / P ACO Time of blood flow through pulmonary capillary