Describe the control of gastric emptying.
This was another important, relevant and essential aspect of basic physiology, for which
candidates tended to lack sufficient breath and depth of the required knowledge. For a good
answer candidates were expected to mention liquids empty much faster (and in an exponential
fashion) than solids (which have a linear pattern), rate of emptying depends on the pressure
gradient generated by the antrum against pyloric resistance. Antral pump activity is of most
importance and that it is influenced by signals from both the stomach (eg distension) and the
duodenum (volume, osmolarity, pH) and humoral factors (gastrin, cholecystikinin, secretin) and
nervous stimulation (general parasympathetic nervous stimulation enhances gastric motility and
sympathetic stimulation opposes it).
References: Guyton and Hall Textbook of Medical Physiology, Chp 63, Power and Kam, Principles
of Physiology for the Anaesthetists, pg 193