Duodenum

“ As soon as the food is reduced to a state of fluidity, the pyloric orifice of the stomach is unclosed, and it is thrust onwards through the alimentary canal, receiving in the duodenum the secretions of the liver and pancreas, after which it yields to the lacteals its nutrient portion, and the residuum is expelled from the body. ”

“ DISEASES OF THE LIVER. Liver complaints are always closely related to other diseases of the digestive organs. The colon being clogged, the intestines are rendered sluggish, which in turn acts upon the duodenum, or second stomach, and prevents the food from properly passing out—then fermentation takes place. Bile is poured out on the accumulated food again and again, for the presence of anything in the duodenum is a demand for the secretion of bile. ”

“ Icterus, clay-colored stools, and bile in the urine show that the catarrh is in the duodenum and involves the opening of the common bile-duct. The absence of diarrhoea, with flatulence and colics, limits the area of inflammation to the duodenum. Symptoms of duodenal indigestion accompany this form of catarrh; the failure of bile to neutralize the acid chyme impairs the effect of the pancreatic secretion. Fats are not digested and there is fatty diarrhoea. ”

“ The duodenum is not a U-shaped loop, but makes one together with the stomach; the pancreas lies between it and the stomach, and is more compact than the rabbit's. There is no separate pancreatic duct, but the bile duct runs through the pancreas, and receives a series of ducts from that gland as it does so. The ileum is shorter, there is no sacculus rotundus, and the large intestine has no caecum, none of the characteristic sacculations of the rabbit's colon, and does not loop back to the stomach before the rectum section commences. ”

“ Intestinal Digestion.—The chemical changes which food undergoes in the small and large intestines are exceedingly complex. Digestion in the intestine is due to the combined action of the bile, pancreatic juice, and succus entericus. The material which enters the duodenum from the stomach is known as the chyme. The acid chyme provokes a flow of bile and pancreatic juice. It acts upon the prosecretin in the duodenal mucous membrane in such a manner that secretin, a hormone, is formed and carried by the blood to the cells of the pancreas which it stimulates. ”

“ With fixation of the hepatic flexure and adhesion of the ascending colon, such as occurs in man, the duodenum is carried dorsad against the ventral surface of the right kidney, and now anchoring of the duodenum, by obliteration of the mesoduodenum and adhesion to the prerenal parietal peritoneum, takes place as already detailed above. To return now to the formation of the duodeno-jejunal fossa by means of this fold, as illustrated in the cat. Perform the manipulations already described in rotation of the intestine. ”

“ The enterotome is then placed through the pylorus and the duodenum cut in the median line of its anterior wall throughout its entire length. When the duodenum is opened, the papilla, the ductus choledochus and the ductus Wirsungianus are to be carefully examined. The papilla can usually be easily found by stretching the duodenal mucosa transversely over the head of the pancreas. It lies below the middle of the head of the pancreas, and about four finger-breadths below the pylorus. ”

“ After the delay in the stomach, the food-substances make another halt in the duodenum, which, being very thin and slender, would have great difficulty in containing them at the time of their grand entry, an hour or two after a meal, were it not that it possesses the property of expanding itself to such an extent, that it swells out on grand occasions to the usual size of the stomach itself, so that it has sometimes been considered as a second stomach. ”

“ An epidemic of duodenitis26 has been reported where many persons were simultaneously attacked, all the cases having had the same traits—headache, pain in the line of the duodenum at the left edge of the right hypochondrium, pain in the first and second lumbar vertebræ, constipation, jaundice, slow pulse, and mental depression. ”

“ And it is not at all strange that they should, since there is so much pressure from within, so much pressure downward, and so much pressure from without—all through the requirements of fashion, indulgence, and ignorance. But the stomach, upper portion of the duodenum, and small intestine, cæcum, the ascending colon, and especially the transverse colon and sigmoid flexure, are susceptible to various forms of displacement, inhibiting the ready flow or passage of food stuffs, gases, and feces from one segment of the digestive apparatus to another, until the vent is reached. ”

“ It may also result from constipation and a resultant absorption of toxic matter as described above.
Many cases of billiousness are occasioned by obstruction of the opening of the bile ducts into the intestines, which is often occasioned by an excess of mucus in the duodenum. In such cases exercise for the intestines is clearly indicated.
In the bending, twisting and squirming movements which the infant in the cradle makes, the liver is regularly squeezed and relaxed. The same is true in the free movements of an active child at play. ”

“ The pharynx communicates with the exterior through five gill slits (g.s.) , and has, of course, no glottis or other lung opening. There is a wide oesophagus passing into a U-shaped stomach (st.) , having, like the rabbit's, the spleen (sp.) on its outer curvature. There is no coiling small intestine, but the short portion, receiving the bile duct (b.d.) and duct of the pancreas (pan.) , is called the duodenum (d'dum.) . The liver has large left (L.lv.) ”

“ From the important and complex function of the intestinal juices, and the very great share they take in the solution of food, there must be many phases of departure from the normal state. The processes of intestinal digestion are more intricate than those of gastric digestion, of a higher grade, and the chemical reactions are more numerous, depending upon the participation of the bile, the pancreatic juice, and the succus entericus; while intestinal absorption is a more complex act than that of gastric absorption. ”

“ Hitherto we have been accustomed to regard the phases of digestion, gastric digestion, pancreatic digestion, and intestinal digestion, as almost separate processes, any of which we might increase indefinitely without doing any harm to the patient. We forget the relation which each bears to the other; and yet such a relation undoubtedly exists, for we find that when pepsin is mixed with bile it is precipitated and rendered inert. Further transformation of foods by the gastric juice is thus arrested as soon as the chyme leaves the stomach. ”

“ Not only do they themselves offer difficulty, but they smear over the other food masses and make it hard for the digestive juices to get at them. Although the enzyme for digesting fat is secreted by the pancreas, its successful working depends on the presence of bile from the liver. If there is an obstruction of the bile passages, so that bile cannot be poured out into the small intestine, the digestion of fats stops and, along with it to a considerable extent, all the other digestive processes of the intestine. ”

“ Intestinal Digestion.—As it leaves the stomach, the partially digested mass of food is intensely acid, from the large quantity of gastric juices which it contains. Intestinal digestion cannot begin until the food becomes alkaline. The alkaline bile neutralizes the gastric juice, and renders the digesting mass slightly alkaline. The bile also acts upon the fatty elements of the food, converting them into an emulsion. The pancreatic juice converts the starch into grape-sugar, even acting upon raw starch. It also digest fats and albumen. ”

“ From what we have just said it is evident that the proper emptying of the stomach and, therefore, the proper carrying on of the whole process of digestion, depends upon the formation and outpouring of ample supplies of acid-containing gastric juice. A failure of gastric secretion is bound to be followed by a failure of the stomach to empty itself. Instead of going on to the small intestine where digestion is completed and the digestion products passed on to the blood stream to be used by the body, the food mass lies inert in the stomach. ”

“ In a state of health the abundantly secreted gastric juice speedily redissolves the chief part of the curd in the stomach, while when it has passed into the intestine the alkaline bile which there becomes mixed with it, completes its solution, and converts the whole into a fluid which closely resembles one of the chief elements of the blood, is consequently very easily taken up by the minute vessels whose office it is to do so, and thus supplies with nourishment the whole body. ”

“ He proved that bile, which used to be considered an excretion, was really an important digestive secretion. He was not able to demonstrate the function of bile as completely as he had done for the gastric juice. The problem of intestinal digestion is much more complicated than that of stomach digestion, and involves a number of factors for which allowance has to be made if the value of any one of them is to be accurately determined. Even in our own day all of the physiological problems in the functions of biliary secretion are not solved. ”

“ Solid food given to the child before it has cut its teeth, enters the stomach unreduced to pulp by the grinders, and unmixed with the saliva, which should help its solution, and which the undeveloped salivary glands do not yet furnish. Too large a quantity of food, or food of an unsuitable character, on which the gastric juice cannot act readily, may pass into a state of fermentation; vomiting, flatulence, sour and offensive breath will be the result, and the food will pass into the intestine unprepared to be acted on by the bile. ”

“ The large intestines are easily cured, but the small ones with difficulty, and the jejunum is utterly incurable, from the multitude of its convolutions and the magnitude of its vessels, and owing to its coats being thin and nervous; besides, it receives all the bile in an undiluted state, and is nearest to the liver. The under and fleshy parts of the stomach we may attempt to cure, for we may succeed, not only because these parts are thicker, but because curative medicines are more readily applied to them, owing to their situation. ”

“ Adjuvants to Digestion.—In atony of the stomach the gastric mucous membrane responds feebly to the stimulus of food. There is failure in both muscular movement and gastric secretion, with slowness of digestion as a result. To meet this condition we seek to increase the digestive power by the addition of certain principles natural to the digestive process—viz. the mineral acids, pepsin, and pancreatin. Of these acids, the hydrochloric should be preferred, because it is the natural acid of the gastric juice. ”

“ Further, the stomach as a reservoir is very useful in bringing everything to a proper and constant temperature before allowing its entry into the intestine. Another fact of some importance is that, contrary to the general view, absorption from the stomach of the products of digestion is not very rapid under ordinary conditions. Even water and soluble salts pass very slowly into the circulation from the stomach. Like the partially digested food material, they are carried forward through the pyloric sphincter into the intestine, where absorption of all classes of material is most marked. ”

“ Experience shows that the delicate stomach suffers severely from these causes. In some instances, the long unemployed organ secretes an excess of mucus, which greatly interferes with digestion. A sufficient amount of food at breakfast has a direct influence on the digestion of dinner; in which process, large quantities of gastric juice—a fluid charged with nitrogenous and other materials—must be suddenly extracted from the blood. ”

“ The retention of fluids, transuded serum, bile, intestinal juices, and partly-altered food is hurtful. Decomposition sets in and gas is developed, which by distending the bowel causes great suffering and increases the inflammation. The movements of the intestine are not entirely under control; the patient must be fed; digestion and assimilation involve the activity of inflamed parts. The stomach can be made to do most of the work, but the sympathy of action is so close between the stomach and intestines that one cannot function without the other being excited into activity. ”