ELECTRICAL ACTIVITY OF ALIMENTARY TRACT

It is possible to describe the characteristic electrical activities of single cells and groups of intestinal muscle cells in terms of slow waves and spikes, but these activities vary depending upon interactions with other cells (nerves, muscle layers, etc.). The mechanism underlying these cellular interactions is not yet understood, but it is possible to say that the activities of cells grouped in certain arrays cannot be deduced from the activities of component cells in isolation (e.g., longitudinal and circular muscle separate and together, circular muscle in very fine strips and in larger strips, resistance between 2 cells and across a single cell). It is possible to believe, although proof is lacking, that most interactions between muscle cells are electrical, although chemical interactions between nerve and muscle cells are probable. Whether or how slow waves in muscles affect nerves is unknown. How nerves or other structures susceptible to anoxia affect slow waves is also unknown. A complete discussion of the relationship between electrical and mechanical activity is beyond the scope of this paper, aside from the statement that slow waves usually trigger spikes and spikes trigger contraction. How slow waves exert control over muscle excitability to bring about the complex motility patterns of the intestine was not discussed; little is known. © 1968 Hoeber Medical Division • Harper & Row, Publishers, Incorporated.