The dissector's manual of practical and surgical anatomy / By Erasmus Wilson.

  • Wilson, Erasmus, Sir, 1809-1884.
Date:
1856
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Licence: Public Domain Mark

Credit: The dissector's manual of practical and surgical anatomy / By Erasmus Wilson. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    Tlie mucous coat in the stomach is thin at the great extremity, and thicker towards the pyloric extremity. It is of a pinkish color, the depth of color being greater in infancy than in the adult, and less in old age ; and being increased under the excitement of digestion. It is, moreover, formed into plaits or rugce, which are disposed for the most part in a lon- gitudinal direction. The rugae are most numerous towards the lesser end of tho stomach; while around the cardiac orifice they assume a radiated arrangement. At the pylorus the mucous membrane forms a circular or spiral fold which constitutes a part of the apparatus of the pyloric valve. In the lower half of the duodenum, the whole length of the jejunum, and the upper part of the ileum, it fomis valvular folds called valvuloi co;i«ife«fes, which are several lines in breadth in the lower part of the duodenum and upper portion of the jejunum, and diminish gradually in size towards each extremity. These folds do not entirely surround the cylinder of the intestine, but extend for about one half or three-fourths of its circumference. In the lower half of the ileum the mucous lining is without folds; hence the thinness of the coats of this intestine as compared with the jejunum and duodenum. At the termi- nation of the ileum in the c?ecum, the mucous membrane fonns two folds, which are strengthened by the muscular coat, and project into the csecum. These are the ileo-ccecal valve (valvula Bauhini). In the cje- cum and colon the mucous membrane is raised into crescentic folds, which correspond with the sharp edges of the sacculi; and, in the rec- tum, it forms three valvular folds,' one of which is situated near the commencement of the intestine ; the second, extending from the side of the tube, is placed opposite the middle of the sacrum; and the third, which is the largest and most constant, jirojects from the anterior wall of the intestine opposite the base of the bladder. Besides these folds, the membrane in the empty state of the intestine is thrown into longitudinal plaits, somewhat similar to those of the oesophagus ; these have been named the columns of the rectum. The mucous membrane of the rectum is connected to the muscular coat by a very loose cellular tissue, as iu the cDsophagus. Structure of Mucous Membrane.—^[ucous membrane is analogous to the cutaneous covering of the exterior of the body, and resembles that tissue very closely in its structure. It is composed of two layers, epithelium and corium. The epithelium is the epiderma of the mucous membrane. Tliroughout the pharynx and oesophagus it resembles the epiderma, both in appear- ance and character. It is continuous with the epiderma of the skin at the margin of the lips, and terminates by an irregular border at the cardiac orifice of the stomach. At the opposite extremity of the canal it terminates by a scalloped border just within the verge of the anus. In the mouth it is composed of laminns of cytoblasts, colls, and polyhedral scales. Each cell and each scale possesses a central nucleus, and within the nucleus are one or more nucleus-corpuscles. According to Mr. Nasmyth,^ the deepest lamina of the ei)ithelium appeai-s to consist of ' Mr. Ilouston, On the Mucous Membrane of the Rectu^m. Dublin Hospital Kej)orts, vol. v. '^ Investigations into tho Structure of the Epithelium, presented to tho medical section oftlie British Medical Association, in 1S31\ ]niblished in a work entithMl Three Memoirs on the Development of the Teeth and Epithelium, 1841.