. Elements of human physiology. Physiology. 314 PHYSIOLOGY Different effects are obtained according as the chorda tympani or the sympathetic fibres are stimulated. Stimula- tion of the chorda tympani in the dog gives rise to an active dilatation of the vessels of the gland, and a copious watery secretion containing only a small amount of mucin and formed elements. Stimulation of the sympathetic causes constriction of the vessels, and a scanty flow of very thick viscid saliva, rich in Fig. Diagram of nerve-supply to submaxillary gland. Sub- maxillary gland. Lingual nerve.
. Elements of human physiology. Physiology. 314 PHYSIOLOGY Different effects are obtained according as the chorda tympani or the sympathetic fibres are stimulated. Stimula- tion of the chorda tympani in the dog gives rise to an active dilatation of the vessels of the gland, and a copious watery secretion containing only a small amount of mucin and formed elements. Stimulation of the sympathetic causes constriction of the vessels, and a scanty flow of very thick viscid saliva, rich in Fig. Diagram of nerve-supply to submaxillary gland. Sub- maxillary gland. Lingual nerve. Chorda tympani. Submaxillary ganglion. Wharton's duet. Jugular vein. Carotid artery. Superior cervical ganglion. Sympathetic fibres ramifying on facial artery. (After Foster.) mucin and formed elements. The changes that occur in the cells are much more marked under sympathetic than under chorda stimulation. In consequence of the differences in the action of these two sets of nerve-fibres, they have been supposed to have two distinct functions. The chorda fibres are vaso-dilator and secreto-motor of water; the sympathetic fibres are vaso-constrictor and secreto-motor of organic matter. The latter have been also denoted trophic, because of the marked change in the cells that is caused by their stimulation. They might well be called the katabolic fibres of the gland. There is no doubt that the difference in the action of the two sets of nerves is in some degree dependent on the variations in the blood-supply produced at the same time, and that the chorda saliva is more watery because the gland- cells have more fluid at their disposal. According to Langley the actions of the gland-fibres of the sympathetic and. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Starling, Ernest H
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