Respiratory membrane a Is the structure through which oXygen diffuse from the alveolus into the blood. and carbon dioxide in the opposite direction alveolus capillary endothelial cell surfactant epithelial cell red blood cell interstitial space
Respiratory membrane surfactant epithelial cell interstitial space alveolus capillary red blood cell endothelial cell O2 CO2 ◼ Is the structure through which oxygen diffuse from the alveolus into the blood, and carbon dioxide in the opposite direction
Ventilation- perfusion ratio通气/血流比值 a Alveolar ventilation(=4.2 L a Pulmonary blood flow(Q)=5L a V/Q=0.84(optimal ratio of air supply and blood supply
Ventilation-perfusion ratio 通气/血流比值 ◼ Alveolar ventilation (V) = 4.2 L ◼ Pulmonary blood flow (Q) = 5 L ◼ V/Q = 0.84 (optimal ratio of air supply and blood supply)
Ventilation-perfusion ratio Effect of gravity on V/Q Top(Apex) pulmonary Physiologic dead space circulation Physiologic shunt Bottom rib cage diaphragm
Ventilation-perfusion ratio VA/QC Effect of gravity on V/Q Physiologic dead space Physiologic shunt
Pulmonary hrombosis Bronchospasm V/Q Normal v/Qt vQ↓ Mismatching of the air supply and blood supply in individual alveoli The main effect of ventilation-perfusion inequality is to decrease the Po, of systemic arterial blood
Normal Mismatching of the air supply and blood supply in individual alveoli. The main effect of ventilation-perfusion inequality is to decrease the Po2 of systemic arterial blood
Gas transport in the blood a Respiratory gases are transported in the blood in two forms Physical dissolution Chemical combination Alveoli Blood Tissue O2 dissolve-combine-dissolve7O2 cO2 dissolve← combine← dissolve←CO2
Gas transport in the blood ◼ Respiratory gases are transported in the blood in two forms: – Physical dissolution – Chemical combination Alveoli Blood Tissue O2 →dissolve→combine→dissolve→ O2 CO2 ←dissolve←combine←dissolve← CO2