Explain the detection and response to hypoxaemia.
A logical approach to answering this question included a definition of hypoxaemia and then a discussion of the sensors, integrators and effectors involved. It was expected that candidates would cover the peripheral chemoreceptor response (including the respiratory, cardiovascular and autonomic effects), time course of the ventilatory response, hypoxia-inducible factors, vascular effects (hypoxic vasoconstriction in the pulmonary circulation and vasodilatation in the systemic circulation) and metabolic changes (switch to anaerobic metabolism). No marks were awarded for discussing the causes of hypoxaemia. Many candidates incorrectly stated that hypoxaemia is detected by the central chemoreceptors.
Definition of hypoxaemia
Detection of hypoxaemia
Response to hypoxaemia
Semenza, Gregg L. "Hypoxia-inducible factors in physiology and medicine." Cell 148.3 (2012): 399-408.
Ward, D. S., S. B. Karan, and J. J. Pandit. "Hypoxia: developments in basic science, physiology and clinical studies." Anaesthesia 66 (2011): 19-268.
Fukuda, Yasuichiro, et al. "Autonomic nerve and cardiovascular responses to changing blood oxygen and carbon dioxide levels in the rat." Journal of the autonomic nervous system 28.1 (1989): 61-74.