Topics
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5. Gas Exchange
Subheadings– Oxygen transport and storage– Oxygen consumption and delivery– Oxyhaemoglobin dissociation curve– Hypoxia– Carbon dioxide Oxygen transport and storage The transport of oxygen flows along a cascade of pressure, from a higher pressure source (atmosphere, 21 kPa) to a lower pressure destination (mitochondria, <5 kPa). At each stage in this cascade there is a subsequent…
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4. Ventilation and Perfusion
Subheadings:– Ventilation-perfusion (V/Q) relationship– Dead space– Shunt– Pulmonary circulation Ventilation Perfusion (V/Q) relationship Ventilation (V) refers to the movement of air into an alveolar space, whilst perfusion (Q) is the flow of blood to an alveolar space. Ventilation and perfusion are two partners of a relationship that is required for gas exchange. There are numerous…
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3. Lung Volumes and FRC
Lung volumes and capacities Lung volumes refer to the volume of gas within the lungs at different times during the inspiratory cycle. Normal tidal breathing, which is the respiratory pattern when at rest, has a volume (tidal volume) of around 500ml, including both inspiration and expiration. At end inspiration on tidal breathing, we still have…