body parts, organs, or systems, separated from the body and placed in an artificial nutrient medium and temporarily retaining their principal functional properties.
Muscle, nerve, intestine, uterus, heart, extremity, head, and organs may be isolated. In physiology, isolated organs can be used to study certain aspects of organ activity; in pharmacology, to elucidate the action of medicinal substances and poisons. Complete isolation from the central nervous system makes possible the investigation of mechanisms of local regulation. Thus, it was established on an isolated heart that the character and intensity of heart contractions depend not only on the influence of the central nervous system and the effect of humoral factors but also on the degree of expansion of the fibers of the heart muscle and regulation by intracardiac neural formations. Comparatively simple conditions are required to preserve the viability of the isolated organs of cold-blooded animals. Thus, to maintain the functional capacity of a neuromuscular preparation from a frog for several hours it is necessary only to prevent it from drying out by moistening it periodically with normal saline. Isolating organs of warm-blooded animals is considerably more difficult: immediately after separation from the body it is necessary to provide for the delivery of nutritive substances and oxygen and the removal of metabolic products and to maintain the temperature at 37°-38°C. Isolation of the brain or head presents an especially difficult problem. Isolated organs taken from a donor or corpse are also used in transplants.
G. I. KOSITSKII and I. N. D’IAKONOVA