Describe the role of carbon dioxide in the control of alveolar ventilation.
Better answers considered the role of CO2 in the control of alveolar ventilation in terms of sensors, central processing and effectors - with an emphasis on sensors. Features of central and peripheral chemoreceptors should have been described in detail. The PCO2/ventilation response curve is best described using a graph, with key features of the curve identified (including gradient and axes). Various factors affecting the gradient of this curve and how CO2 affects the response to hypoxic drive should be described.