Fistula, Artificial

in experimental physiology, an opening (canal or passageway) through which a hollow organ communicates with the exterior or with another organ. Artificial fistulas are created by means of special operations for use in prolonged experiments on animals to study the activity of organs of digestion and urinary excretion, the rate of blood flow, and the composition of blood. Metal or plastic tubes are attached to the body and inserted into the cavities of organs or sewn to the walls of blood vessels. The procedure of exteriorizing ureters, salivary ducts, intestines, and segments of the stomach (for example, in sham feeding of animals) is also widely used in physiological experiments. Artificial fistulas can be used to obtain digestive juice in pure form and to study the condition and movements of internal organs, the dynamics of urinary excretion, and the composition of blood flowing out of the organs.