Treatise on human physiology : for the use of students and practitioners of medicine / by Henry C. Chapman.

  • Henry Cadwalader Chapman
Date:
1887
Catalogue details

Licence: Public Domain Mark

Credit: Treatise on human physiology : for the use of students and practitioners of medicine / by Henry C. Chapman. Source: Wellcome Collection.

    135/942 page 147
    eg iE aN] Std Bea ved eae, INTESTINAL DIGESTION. INTESTINAL JUICE. PANCREATIC JUICE. LIVER. GLYCOGEN. BILE. FECES. DEFECATION. We have seen that shortly after food is taken into the stomach it passes in small quantities through the pyloric orifice into the small intestine, or the part of the alimentary canal intervening between the stomach and the ilio-caecal valve. The small intestine is a cylindrical tube and in situ measures on an average from fifteen to eighteen feet, but when separated from the mesentery or the peritoneum, which holds it in position in the abdominal cavity, it will be found to be a little longer—about twenty feet. It has a diameter of about one and a quarter inches. The small intestine is composed, in addition to its external or perito- neal coat, of two others: of a mucous membrane, including an epi- thelial and submucous or fibrous coat (Fig. 54, 4, 5), and of a muscular coat lying exteriorly between the peritoneum and _ the mucous membrane. The muscu- lar coat consists of unstriped Pia, 54. muscular fibre, arranged in two layers, longitudinally or parallel with the long axis of the intestine, and circularly or at right angles with the axis (Fig. 54, 2,3); the circular fibres being better devel- oped than the longitudinal ones. It is through the slow and grad- ual contraction and relaxation of these muscular fibres, the so- called peristaltic or vermicular movement, that the food is pro- | pelled along the intestine, the Portion of the duodenum, viewed from without, contraction of the circular muscu- natural size. 1. Thickness of the duodenum, 2, 3. : . Longitudinal and transverse layers of fibres of the lar fibre at the pyloric orifice pre” muscular coat. 4. Fibrous coat. 5. Exterior of the venting regurgitation into the mucous membrane, with the duodenal glands im- stomach, bedded. (Lxrpy.) Like the movements of the stomach, the natural stimulus to the vermicular motion of the intestine 1s the presence of food, during the intervals of digestion the intestine being at rest. The peristaltic or vermicular motion of the intestine can be well seen by opening an animal in full digestion. What is positively known, however, of the intestinal movements in man is derived from pathological cases where the abdominal walls were so thin that the motion could, to a certain extent, be seen and felt, or from cases of
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