. The animans and man; an elementary textbook of zoology and human physiology. ch narrows at its lower or pyloric end and opensinto the small intestine (fig. 156). mucous liningis covered with minute shallowpits, the openings of thegastric glands. The glands fur-nish certain enzymes, pepsinand rennin, all of which aidin digestion. The pyloric glands(fig. 160), which furnish pepsinonly, lie in the pyloric end ofthe stomach. The fundusglands in the cardiac part ofthe stomach, are formed of sev-eral kinds of cells, and furnishpepsin, rennin and hydrochloricacid. The gastric juice con
. The animans and man; an elementary textbook of zoology and human physiology. ch narrows at its lower or pyloric end and opensinto the small intestine (fig. 156). mucous liningis covered with minute shallowpits, the openings of thegastric glands. The glands fur-nish certain enzymes, pepsinand rennin, all of which aidin digestion. The pyloric glands(fig. 160), which furnish pepsinonly, lie in the pyloric end ofthe stomach. The fundusglands in the cardiac part ofthe stomach, are formed of sev-eral kinds of cells, and furnishpepsin, rennin and hydrochloricacid. The gastric juice containingthese enzymes acts in an acidmedium upon proteid food, while the ptyalin of thesalivary juice acts in an alkaline medium and upon carbo-hydrates. The presence of food or food accessories in the stomachstimulates the flow of gastric juice. Pepsin,--This enzyme changes proteid into a soluble formcalled peptone. It acts at a rather high temperature. Rennin.—This enzyme acts upon milk, causing it to coagu-late or separate into curds (the proteid part) .and whey (mostly. FIG. 160. Section of pyloricglands from human stomach,a, mouth of gland leading intoa long wide duct (b), intowhich open the terminal divi-sions; c, connective tissue ofmucosa. (After Piersoe.) DIGESTION AND ABSORPTION water). This separation prepares it for the action of -This secretion establishes the acid medium necessary for the action of pepsin and may dissolve some of the mineral salts. The cardiac or fundic end of the stomach (fig. 156) acts as a reservoir for the food as it leaves the oesophagus. Here the food may remain for sometime while the starchy matter is further acted upon bythe salivary juice. In the pre-pyloric andpyloric end digestion ofproteid is begun by thegastric juice. This is thesecond stage in results in a milky masscalled chyme, which inpait is ready for absorp-tion and in part needsfurther treatment. Thispasses in small amounts
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Keywords: ., bookcentury1900, bookd, booksubjectphysiology, booksubjectzoology
