Human physiology . folds in the form ofcrescentic projections of the mucous membrane, placed transverselyto the axis of the bowel, at a short distance from one another(valvulae conniventes or valves of Kerkring). The whole surface,including the valvular folds, is closely beset with villi, of varyinglength, cylindrical in the jejunum, filiform in the ileum (Fig. 41),which enormously increase the intestinal surface. The mucouscoat of the large intestine is smooth, and destitute of villi(Fig. 42). Between the villi of the small intestine, in every part, arethe simple tubular glands, Lieberkiihns
Human physiology . folds in the form ofcrescentic projections of the mucous membrane, placed transverselyto the axis of the bowel, at a short distance from one another(valvulae conniventes or valves of Kerkring). The whole surface,including the valvular folds, is closely beset with villi, of varyinglength, cylindrical in the jejunum, filiform in the ileum (Fig. 41),which enormously increase the intestinal surface. The mucouscoat of the large intestine is smooth, and destitute of villi(Fig. 42). Between the villi of the small intestine, in every part, arethe simple tubular glands, Lieberkiihns crypts, which resemblethe fingers of a glove, the orifices being somewhat dilated at the II EXTERNAL DIGESTIVE SECRETIONS 123 extremity. These crypts are more numerous in the large intestine,owing to the absence of villi (Fig. 42). The epithelium by which the crypts are lined is exactlysimilar to that which clothes the surface of the villi. It consistsof irregular columnar cells, with a large nucleus, and striated. ti Fie. 41 (Left).—Section of intestinal mucous membrane (infant), shows three villi, with crypts ofLieberkiihn. (Bohm and v. Davidoff.) >y. e, K, epithelium of villus ; c, connective tissue ofvillus ; re, goblet cells ; cr, Lieberkuhns crypts ; rli, connective tissue at base of gland ; mm,muscularis mucosae. 4-2 (Right).—Section of mucous membrane of human colon, showing three crypts of Lieber-kuhu. (Bnhm and v. Davidott.) 2ju. e, epithelium ; I, lumen of,gland; cc, goblet cells; ti,interglaiidular tissue ; ta, areolar tissue of mucous membrane ; mm, muscularis mucosae. cuticular layer, and a somewhat flattened end which is attachedto the surface of the basement membrane, without extending(as was formerly supposed) into the reticulated tissue of the are seen here and there between the epithelial cells(Fig. 43). Goblet cells produced by mucoid degeneration of the ordinarycolumnar cells are seen between the latter, the outer half of these
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectphysiology, bookyear1
