This section is from the book "Diseases Of The Intestines", by Max Einhorn. Also available from Amazon: Diseases Of The Intestines A Text-Book For Practitioners And Students Of Medicine.
The intestinal tract is rich in ganglionic cells and nerves. The plexus mesentericus Auerbach and the plexus entericus Meissner accompany it through its entire length. The vagus and the splanchnic nerves surround the intestinal canal with numerous branches and form ramifications with the ganglionic plexus. Although a thorough knowledge of the exact action of these different nerve groups has not yet been acquired, still we are certain that they govern the secretory, absorptive, and motor functions of the intestinal canal.
Secretion seems to be dependent a great deal upon the ganglionic plexus, as can be learned from Moreau's 1 experiment. This investigator ligated an intestinal coil and severed all the nerves belonging to it. In a few hours the coil, thus treated, was found filled with a fluid showing amylolytic qualities and containing small quantities of albumin. In order to prove the secretory influence of nerves upon the intestines Fleischer2 justly refers to the fact demonstrated by Quincke, Demant, and Mass-loff,3 that in man as well as in animals after ingestion of food into the stomach, secretion takes place in the lower part of the intestine, long before the arrival of the chyme.
1 Moreau: Centralbl. f. die med. Wissensch., 1868, No. 14. 2 R Fleischer: "Krankheiten des Darins." Wiesbaden, 1896. 3 Massloff: "Untersuchungen aus dem physiologischen Institut zu Heidelberg," Bd. ii.
This also shows that the nerves of the intestinal tract are influenced by reflex action from the nerves or the stomach.
Vasomotor nerve filaments have also been proven to exist in the intestines. Thus stimulation of the splanchnic nerve causes a contraction, while its section is followed by dilatation of the intestinal blood-vessels. These vasomotor nerve filaments are undoubtedly also much concerned with absorption.
The motor function of the nerves and their influence upon peristalsis have been studied in an exhaustive manner by Nothnagel, Brahm-Houkgeest, and others, and have been described in the chapter on physiology (page 28).
Although under normal conditions we scarcely perceive any sensations within the intestinal tract, we are nevertheless certain that sensory filaments exist in the nervous apparatus of the intestines. This is revealed by the fact that the action of some stimuli of greater intensity than normal upon the intestinal wall, gives rise to sensations of pain and pressure. Thus, a person not accustomed to a coarse diet, after ingestion of a large quantity of cabbage and beans, for instance, may suffer after six to eight hours from pains in the lower part of the abdomen caused by the undue irritation of the small intestine. In pathological conditions the sensory character of the intestinal nerves is evinced very frequently. In fact this is one of the important points which we have to consider in almost any affection of the intestinal canal.
The neuroses of the intestine may be classified into: 1, motor neuroses; 2, sensory neuroses; and 3, secretory neuroses. Very often these different neuroses exist in combination. Thus, a motor neurosis may exhibit features belonging to secretory or sensory derangements. The designation of the neurosis, however, should depend upon the type most prevalent. All affections of the intestines in which no anatomical lesion can be discovered are classified as neuroses or functional diseases of the intestines.
Intestinal neuroses may be primary, i.e., the affection emanates from the intestinal tract, or they may be secondary, occurring in connection with nervous manifestations in other organs. Etiologically we know that psychical influences, mostly of a depressing nature, as fear, fright, worry and anxiety, are often the causative factors of intestinal neuroses. Neurasthenia and hysteria as well as a general neurotic tendency are also liable to produce nervous affections of the intestinal tract. In some instances the latter conditions are due to a reflex action originating from some other diseased organ (stomach, the genito-uri-nary tract, uterus, etc.).