Intestine

“ This process is repeated with every food mass as it comes through from the stomach into the intestine until, finally, usually three or four hours after the first food has commenced to come into the intestine from the stomach, the whole mass has been propelled the length of the small intestine and what is left has been passed on through into the large intestine. The small intestine is about twenty-five feet long in man; flesh-eating animals of about the same size have intestines only about one-half as long ”

“ The small intestine commences at the pylorus, winds into many convolutions, and terminates in the large intestine. In the adult it is about 20 feet in length. It is arbitrarily divided into three parts—viz., the duodenum, the jejunum, and the ileum. It constitutes four-fifths of the whole intestines, the larger making up the other fifth. They are used to aid in assimilating the food after digestion, and convey forward the excrementiticus matter. ”

“ The chyme leaving the stomach, enters the small intestine, as we have described and comes in contact with the pancreatic and intestinal juices and with the bile, and intestinal digestion ensues. These fluids dissolve most of the food that has not already been softened. ”

“ The small intestine is the segment of the alimentary canal in which digestion of the non-nitrogenous food substances takes place, and which affords the necessary area of mucous surface for the absorption of all digested matters. ”

“ As the food passes along the colon, pushed slowly ahead by the peristaltic wave, or rhythmic muscular contractions of the intestinal wall, it is seized upon by the four hundred varieties of friendly bacteria which inhabit the intestines of every healthy person, and is changed into a form which the body can assimilate. Digestion in the stomach and small intestine is carried on by means of certain digestive juices, but in the large intestine it is the bacteria which do the work. ”

“ The sphincter between the stomach and small intestine is operated by hydrochloric acid, making up a remarkably ingenious arrangement for securing the emptying of the stomach as fast as the food is ready to be passed on into the small intestine. In order that gastric digestion may have full opportunity, it is necessary that the food should be thoroughly mixed with the gastric juice. ”

“ 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. ”

“ When peritoneal adhesions that cannot be easily torn are present it may be necessary to remove the intestines with mesentery attached.
After the removal of the intestines from the body they are opened by the intestinal shears, beginning either with the jejunum or the large intestine, the cut being made in the line of the mesenteric attachment. As the intestine is opened careful attention should be paid to the contents of each portion. It is very poor technique to dilate the intestine with water or to run water through it before it is opened. ”

“ 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. ”

“ The course of the food in the small intestine.—Chyme is not forced from the stomach by every wave that passes over the antrum, but only at intervals. When the pylorus relaxes, the food, moved towards the pylorus under considerable pressure, is squirted along the duodenum for two centimetres or more. Careful watching of this food shows that usually it lies for some time in the curve of the duodenum until additions have been made to it from the stomach, and a long, thin string of food is formed. ”

“ It serves both as a support and as a medium of attachment to fix the intestine in its place. By its smooth, soft, and lubricated surface, it admits readily of the change of place among the bowels necessarily produced by respiration, exercise, and even by different degrees of distention of the bowels themselves. Every time we breathe, an undulating motion is communicated to the whole intestines, which facilitates their action, but which could not take place unless they were capable of gliding easily and freely over each other. ”

“ The peristaltic movements are greatly increased in rapidity and force, and the faeces are carried rapidly from the upper to the lower parts of the intestine. They are thus passed through the large intestine in so short a time that the fluid they already contain has not time in which to be reabsorbed, a process which apparently takes place normally in the large intestine. At the same time there is a much larger quantity of fluid secreted into the lumen of the intestine than takes place in the normal animal. ”

“ While water and salt are absorbed both in the stomach and in the small intestine, the evident purpose in leaving the larger part of the water to be absorbed in the large intestine is that it may assist the intestinal contents in passing along. ”

“ R, reticulum; C, abomasum; V.c.d., right pouch of the rumen; Ig, small intestine.
116It is by methodically observing, grouping, and classifying the symptoms presented that one is enabled to detect the links connecting them.
Intestine. The intestinal mass is contained in the right half of the abdomen above the compartment of the stomach. The large intestine occupies the upper zone, corresponding externally with the hollow of the flank from the thirteenth rib to the haunch. The small intestine occupies the middle zone from the thirteenth rib to the entrance to the pelvis and the stifle region ”

“ 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. ”

“ At the time when the intestine still presents the primitive arrangement of the umbilical loop (Figs. 104 and 130) this vessel passes between the layers of the dorsal mesentery through the narrow duodeno-colic neck to reach the two limbs and the apex of the intestinal loop. In its course it gives off successively branches to the gut from each side. Those from the right side of the main vessel pass to the duodenum, pancreas, jejunum and ileum. ”

“ The integrity of the functions of the intestines is of supreme importance, for it is here that absorption and assimilation of most 183of our food occurs. If our intestines are not in perfect order we shall soon waste and dwindle away, even within a short period, and sometimes very rapidly. Thus if we wish to retain our strength we must treat the intestine with the greatest care. This is especially the case in old age, for then an atrophy of the glandular mechanism of the digestive tract, stomach, and intestines, takes place. ”

“ The stomach, after a variable length of time, during which the peptic ferments accomplish their allotted task more or less thoroughly and completely, delivers the resultant mass over to the small intestine, where the secretions from the pancreas, liver, and intestinal glands, by finishing the transformation of the starch begun before the stomach was reached, emulsifying the fatty constituents, etc., complete the complex work of digestion. ”

“ When the large intestine is full, palpation through the abdominal wall demonstrates that the material in the lower descending colon and in the sigmoid flexure is usually composed of hard, incompressible lumps, while that in the ascending and transverse colon and the cæcum is soft, permitting the walls of the gut to be easily pushed together. ”

“ Not only the digestion in the stomach, but also the absorption of food transformed into a liquid from the intestines is much assisted by thorough mastication; while, as the result of insufficient mastication, as with fast eaters, the food may cause much greater work to the walls of the stomach. Being much less absorbed from the intestine it may irritate it as a foreign body until expelled by greater efforts of the intestinal walls. ”

“ All substances which, after being taken into the stomach, are not absorbed, which are thus pushed onwards along the inner coat of the intestine, and by their mere accumulation excite its muscular contraction, must operate more or less as indirect purgatives. ”

“ 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. ”

“ During the slow passage of the food mass through the small intestine the processes of digestion and absorption are completed, so that very little material enters the large intestine except the indigestible parts of the original food. ”

“ The food is masticated by a very complicated system of jaws and teeth, and after it has been mixed with a secretion, which is poured into the mouth by salivary glands, it passes through a long muscular œsophagus into the stomach, where it is acted upon by fluids furnished by a liver and other glands, before it passes into the long, convoluted intestine, where the nutritive portions are absorbed into the blood, while the waste products are discharged from the body through the anus. ”

“ Only in our own day has come the greatest confirmation of the notion then first introduced into physiology, of the surpassing importance of intestinal digestion. The removal of the whole stomach for malignant disease is now undertaken without any fears as to the ultimate result on the patient's general nutrition. The operation has been done many times, and the surgeon's confidence that the intestines would compensate, as far as digestion of food was concerned, for the absent stomach has been amply justified. ”

“ This all takes time, and probably from the time they enter the skin to the time they begin their murderous work on the lining of the intestines requires about two months. In the intestine the larvæ develop into adults ”

“ 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. ”

“ Great care should be exercised in the quality of the food. The freshness of various foods is of the greatest importance to the intestines, since the main function of the stomach is principally a mechanical one, serving to reduce the food into a convenient form and carry it to the intestines, ready to be there prepared, through the influence of the intestinal juices, into a condition fit for absorption and assimilation. During this process the food is being reduced to its simpler elements, and the more noxious substances are being freed to commence their baneful activity. ”

“ 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. ”

“ Many believe they have free movements when actually they are suffering from a sluggishness in the rectum and other parts of the lower intestine. A rectal examination often reveals unsuspected fecal residues. ”

“ The other intestines are by association excited into more powerful action, while the lymphatics, that open their mouths into them, suffer an inversion of their motions corresponding with the lymphatics of the stomach, and duodenum; which with a part of the abundant secretion of bile is carried downwards, and contributes both to stimulate the bowels, and to increase the quantity of the evacuations. ”