. The biology of the frog. Frogs. THE DIGESTIVE SYSTEM AND ITS FUNCTIONS 153 of which are produced backward, forming a double series of pockets which tend to check the flow of food in the direction of the stomach. The pockets are connected by smaller folds which run mainly in a longitudinal direction. Farther back, a little beyond the middle of the intestine, the folds lose their regular arrangement, and in the posterior third they assume a longitudinal direction. The large intestine is composed of the same layers as the. Fig. 52.—Part of a cross section of the small intestine of the frog. bl,
. The biology of the frog. Frogs. THE DIGESTIVE SYSTEM AND ITS FUNCTIONS 153 of which are produced backward, forming a double series of pockets which tend to check the flow of food in the direction of the stomach. The pockets are connected by smaller folds which run mainly in a longitudinal direction. Farther back, a little beyond the middle of the intestine, the folds lose their regular arrangement, and in the posterior third they assume a longitudinal direction. The large intestine is composed of the same layers as the. Fig. 52.—Part of a cross section of the small intestine of the frog. bl, blood vessels; eg, goblet cells; ep, ordinary epithelial cell; , submucosa; , circular muscles; , longitudinal muscles; pe, peritoneum. (After Howes.) small. The inner surface is thrown into folds, which at the proximal end form an irregular network, but in the rectum they become longitudinal. The epithelium of the mucosa consists of cylindrical cells, among which numerous goblet cells are to be found. The Pancreas.—The pancreas is an elongated gland of irregular shape situated between the stomach and the duo- denum, and extending from the liver to within a short dis- tance of the pylorus. It is traversed by the common bile. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Holmes, Samuel J. (Samuel Jackson), 1868-. New York : The Macmillan company
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Keywords: ., bookauthorholmessamueljsamuelja, bookcentury1900, bookdecade1920
