Digestive system

“ The degree of development of the digestive fluids, the stomach, and the teeth must be considered in preparing food for an individual child. In infancy the digestive system is undeveloped, lacking in digestive fluids, stomach small, and there is no provision for chewing.
Until nine months of age babies do not have digestive fluids for starch, or for protein except the curds of milk; their teeth are not yet serviceable for chewing, and solid food of any kind is so indigestible that it often causes convulsions, if given. ”

“ After its ingestion, the digestive organs are taxed to their utmost capacity, and soon become loaded and distended with blood. The digestive system is quite extensive, and is richly supplied with blood-vessels, which are imbedded in rather loose tissue, so that they may dilate, to accommodate the sudden influx from the outlying portions of the body, together with the newly-absorbed products of digestion. ”

“ When we reflect that the object of digestion is to furnish materials for the growth of the body, and to supply the waste which the system is constantly undergoing, it must appear self-evident, that, if the digestive powers be impaired by disease, by improper quantity or quality of food, or by any other cause, the result must necessarily be the formation of an imperfect chyle, and consequently of imperfect blood. ”

“ Not only that the progress of digestion is thus interrupted, not only that the body derives no strength from the inert mass of ingesta, but that mass, by undergoing a putrid instead of peptic decomposition, vitiates the humors of the system it was intended to nourish, irritates the sensitive membranes of the stomach, and gradually impairs the vigor of the whole digestive apparatus. ”

“ 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. ”

“ If the eliminating power of the intestinal canal is normally active, the fortunate individual may eat abundantly, or really in excess of the requirements of the system, and still escape any ill effects, such as indigestion, biliousness, acid in the urine, etc. The hearty consumer of food whose bowels eliminate properly may suffer a loss of appetite, but it will not be accompanied with foulness of the digestive apparatus.
When all the organs of the body perform their functions in a normal manner, no part of the structure is in immediate need of repair. ”

“ If any part of the digestive function is deficient, impaired health, or mental and physical inefficiency expressed in the form of indigestion, is the result. If [Pg 304] the bowel is at fault, constipation is the usual consequence. A perfectly healthy living machine must maintain a perfect digestion and regular bowel movements.
The Function of the Stomach is to mix and churn the food, and to add certain ingredients to the mixture so that before it is carried into the intestines it is (as far as it is the stomach's duty to render it) ready to be absorbed into the system. ”

“ Here, as elsewhere in the digestive tract, the muscles are involuntary, muscular action being under the control of the so-called sympathetic nervous system. Food material in the stomach makes several complete circuits during the process of digestion in that organ. Contrary to common belief, the greatest amount of food is digested after it leaves the stomach. But this organ keeps the food in it in almost constant motion for a considerable time, a meal of meat and vegetables remaining in the stomach for three or four hours. ”

“ The process of digestion is finally ended in the intestines, where absorption into the system takes place. There is no opening at all from the bowels into the body, but the digestive nutriment is picked up by the blood when handed into the body from the intestines by means of countless little cells called villi, that line the walls of the intestines. These villi cells have little hair-like projections extending into the intestines, which constantly move ”

“ Liquids are rapidly removed from the stomach by absorption. Hence, in cases of great prostration, when it is desirable to introduce nutriment into the system, without delay, the animal and vegetable broths are a desirable and convenient form of supplying aliment.
323. The condition of the skin exercises an important influence on the digestive apparatus. Let free perspiration be checked, either from uncleanliness or from chills, and it will diminish the functional action of the stomach and its associated organs. ”

“ The OMENTUM (caul) consists of four layers of the serous membrane, which descends from the stomach and transverse colon. A quantity of adipose matter is deposited around its vessels, which ramify through its structure. Its function is twofold in the animal economy. 1st. It protects the intestines from cold. 2d. It facilitates the movements of the intestines upon each other during their vermicular, or worm-like action.
258. Every part of the digestive apparatus is supplied with arteries, veins, lymphatics, and nervous filaments, from the ganglionic system of nerves. ”

“ I refer to the production of gastric juice in the empty stomach, as a result merely of the swallowing of food in the so-called sham feeding of an œsophagotomised dog. When one takes into consideration the absolute independence of this factor, and the intensity of the effect, which makes itself evident in the secretion of a large quantity of juice of high digestive power, the exciting agency which brings about such secretion must be recognised as one of the most important and effective processes in gastric digestion. ”

“ We will now examine briefly the organs and their secretions that convert food-substances into blood, and, by the blood, into tissue.
The solvents and diluents of food in the human animal economy are the saliva of the mouth, the gastric juice of the stomach, the pancreative juice of the pancreas, the bile of the liver, and the juices of the intestines—the succus entericus.
The digestive apparatus consists mainly of the alimentary canal together with various glands of which it receives the secretions. ”

“ Ruminating animals, or animals which chew the cud, such as the Cow, have several stomachs, and the food undergoes mastication several times, at each time being passed into a different stomach, before being finally acted upon by the gastric juice, after which it is transmitted through a long tract of intestines. This is an example of the most complex 360 digestive organ fitted to act upon hard and fibrous food, which must be subjected to the action of several menstrua preparatory to its being acted upon by the gastric juice. ”

“ On the other hand, if we bear in mind the whole mechanism of digestion, it will readily be seen that, in cases of weakness or want of tone on the part of the muscles of the stomach, when every part of the food cannot be properly presented to the action of the digestive juices, the introduction into the stomach of a moderate amount of water may be of no slight benefit. ”

“ 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 lack of a sufficiently vigorous flow of blood is followed by deficient secretion of digestive agents from the glandular elements involved, by decreased motility of the muscular coats of the stomach and bowel, and lessened adaptability throughout for dealing with even slight irregular demands on their powers. ”

“ It is impossible for the stomach to perform its duty satisfactorily if it is never allowed rest, and the introduction of stray morsels of food at irregular times prevents this, and introduces confusion into the digestive work, because there will be in the stomach at the same time food in various stages of digestion. ”

“ Perhaps the most important result of giving plenty of time to the taking of food is that of stimulating the digestive glands to a proper degree of activity. That both the salivary and gastric glands are excited by the sight, smell, and thought of food and, through taste, by the presence of food in the mouth, has been fully demonstrated. Food that is thoroughly masticated and relished will receive more saliva and gastric juice, and probably more of other juices, than if hastily chewed and swallowed. ”

“ Digestion is aided by the movements of the food mass through the contractions of the walls of the stomach, so that anything which lowers the tone of the stomach or impairs the integrity of its lining membrane seriously interferes with the digestive processes. ”

“ 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 digestive processes, the main purpose of which is to break up the carbohydrates, proteins, and fats into substances of much simpler chemical structure, begin in the mouth and are not completed until some time after the food has entered the intestine. As the food moves through the alimentary canal, it is mixed with the various digestive juices containing ferments, such as pepsin, which are the active agents of digestion. Although digestive processes go on automatically, they are, in a degree that is far from negligible, influenced by the mind. ”

“ 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. ”

“ It acts as a digestive organ of importance in preparing the food for further attack in the intestinal canal. But the stomach cannot be regarded as an essential organ, since it has been removed in dogs and in man without apparent interference with nutrition and health. Gastric digestion is brought about by the action of the gastric juice, a clear watery, colourless and strongly acid fluid with a specific gravity of about 1003. ”

“ The normal stool is a mixture of— (a) Water; (b) undigested and indigestible remnants of food, as starch-granules, particles of meat, plant-cells and fibers, etc.; (c) digested foods, carried out before absorption could take place; (d) products of the digestive tract, as altered bile-pigments, mucus, etc.; (e) products of decomposition, as indol, skatol, fatty acids, and various gases; (f) epithelial cells shed from the wall of the intestinal canal; (g) harmless bacteria, which are always present in enormous numbers. ”

“ How very powerful a human stomach may sometimes be, and how large a task in the way of digestion it may sometimes perform without complaint, is known to those who have had the opportunity of observing what certain persons with exceptional power are accustomed to take as food, and do take for a long time apparently with impunity. But these are stomachs endowed with extraordinary energy, and woe be to the individual with a digestive apparatus of moderate power who attempts to emulate the performance of a neighbor at table who perchance may be furnished with such an effective digestive apparatus! ”

“ Comminution of hard food is of first importance, undoubtedly, but insalivation and neutralisation or alkalinisation are, seemingly, much more easily and quickly accomplished in the mouth than farther on in the alimentary canal. The intestines can do all in the way of digestion, even if the mouth and stomach are passed and their assistance in the digestive process is entirely neglected, but it is done at tremendous disadvantage in the supplementary digestive tract of the intestines. ”

“ The mid-gut is essentially the digestive and absorptive region of the alimentary canal, and its surface is, in most cases, increased by pouch-like or tubular outgrowths which not only serve as glands for the secretion of the digestive juices, but may also become filled by the more fluid portion of the partially digested food and facilitate its absorption. ”

“ To this it may be replied, that the stomach is subject to the same law as the muscles and other organs; exercise, within certain limits, strengthens it. If, therefore, we always eat those articles most easily digested, the digestive powers will be weakened; if over-worked, they will be exhausted. Hence the kind and amount of food should be adapted to the maintenance of the digestive powers, and to their gradual invigoration when debilitated.
Observation. Food that is most easily digested is not always most appropriate to a person convalescing from disease. ”

“ When we remember that it takes food from twelve to twenty-four hours to reach the rectum, and that it has during all that time been subjected to the action of the powerful chemicals of the digestive tract, it is hard to imagine a piece of cheese, of whatever variety, strong enough to stop the contraction of the muscles of the upper rectum or to tie the sphincter-muscle into a knot. It would be difficult to find a food which could pass without effect through twenty-seven feet of intestinal tubing only to become suddenly effective on the wall of the rectum. ”