Annual report of the Medical College of Bengal : fourteenth year, session 1848-49 / under the immediate control and superintendence of the Council of Education.
- Medical College of Bengal
- Date:
- 1849
Licence: Public Domain Mark
Credit: Annual report of the Medical College of Bengal : fourteenth year, session 1848-49 / under the immediate control and superintendence of the Council of Education. Source: Wellcome Collection.
Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.
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![the 2nd in its passage from the ktter to the ])harynx, and the 3rd and last stage in its passage from the jiharynx through the oesophagus, into the stomach. lu the 1st stage the mouth is closed and the tongue raised against the hard palate. The second stage is very com]>licated. In it, just as the food has passed the anterior jiulatine arches, the palatoglossus muscles of the two sides C(nitract and are drawn in like side-curtains which together with the uvula close the openings into the mouth and the posterior nares, now the food may pass into the laryn.x—this is, however, prevented by the tongue being brought backwards by the styloglossi muscles, and the larynx, raised against its imder-surface by its proper elevators. When all this is accomplished, the stylo-pharyngei act and dilate the pharynx sideways, and the food passes down along an inclined plane into the pharynx. Now commences the 3rd stage—in it the con- structor muscles of the jiharynx, and the longitudinal and circular mus- cular fibres of the oesophagus (the latter especially), act and the food is thereby brought down into the stomach to undergo some of the most important changes that take place in the ])rocess of digestion. (3.) Mooements of the stomach. These principally consist 1 in the passage of the food from the cardiac extremity into the great cul de sac or the splenic end of the stomach, and from the latter and along its great curvature to its pyloric end, and 2 in its return from the pyloric, along the lesser curvature, to the cardiac end. These varied movements are effected by the muscular coat of the stomach, which consists of longitu- dinal, transverse or circular and oblique fibres. Wliile the process of digestion is going on, the stomach assumes a sort of hour-glass shape, it being constricted in the middle by the contraction of its circular fibres— It is also provided with a sort of sphincter muscle in its cardiac orifice, this is formed by its oblique fibres and prevents the reflux of the food into the oesophagus. (4.) Movements of the intestines. After undergoing certain changes in the stomach, the food ])asses into the intestinal canal and in its passage along it excites what are called paristaltic movements in the different parts with which it comes in contact. The ajjparatus that cfTccts these move- ments is the muscular coat of the small and large intestines, which consists of longitudinal fibres externally and circular, internally. Now for the changes, the food undergoes in the different parts of the alimentary canal. These may be described in the following order 1 changes it suffers in the mouth, 2 in the stomach and 3 in the intestinal canal. (1.) In the mouth, the food is first triturated by the organs of attri- tion, the teeth, and then mixed with the Saliva. These two processes are respectively called mastication and In salivation, the former is ))urely mechanical in its character, and the latter involves certain changes in the food which are not well understood.—It has been found by experiments that the Saliva has the power of converting starch into sugar, and it may in virtue of this property be of some use in digestion. That it effects any chemical changes in the food is, however rendered improbable on the ground of the very short time, the latter is acted upon the Saliva. There is no doubt I believe as to the fact of this secretion being essential to digestion—Spallanzani has found by several experiments that the same food, which is easily digested by the gastric fluid when it has been previously imbued with the Saliva, is hard of digestion when it has not been so treated. (2.) The changes the food imdergoes in the stomach are solution and chemical change. They are effected Ijy the gastric fluid which is secreted](https://iiif.wellcomecollection.org/image/b24766823_0065.jp2/full/800%2C/0/default.jpg)
