A treatise on physiology and hygiene for educational institutions and general readers .. . hichfood enters, being situatednear the heart, is called thecardiac, or heart orifice; theother is the pylorus, or gatekeeper, which guardsthe entrance to the intes-tines, and, under ordinarycircumstances, permits onlysuch matters to pass it ashave first been properlyacted upon in the , buttons, and the likeare, however, readily allowedto pass, because they can be of no use if retained. The soft andyielding texture of this organ—the stomach—indicates that it is notdesigned to crush and break
A treatise on physiology and hygiene for educational institutions and general readers .. . hichfood enters, being situatednear the heart, is called thecardiac, or heart orifice; theother is the pylorus, or gatekeeper, which guardsthe entrance to the intes-tines, and, under ordinarycircumstances, permits onlysuch matters to pass it ashave first been properlyacted upon in the , buttons, and the likeare, however, readily allowedto pass, because they can be of no use if retained. The soft andyielding texture of this organ—the stomach—indicates that it is notdesigned to crush and break up solid articles of food. 24. The Gastric Juice.—We have seen how the presence offood in the mouth excites the salivary glands, causing the salivaquickly to flow. In the same manner, when food reaches thestomach, its inner lining, the mucous membrane, is at once excitedto activity. At first, its surface, which while the stomach is empty 23. Heart-orifice? Gatekeeper? Coins, Indication of the soft and yielding textureof the stomach ? 34. What is meant by the gastric juice?. Fio. 26.—Section of Chest and Abdomen. A, Heart. B, The Lungs. C, Diaphragm. D, The Liver. E, Gall Bladder. F, Stomach. G, Small , Large Intestine. DIGESTION. 115 presents a pale pink hue, turns to a bright red color, for the minuteblood-vessels which course through it are filled with blood. Pres-ently a clear, colorless, and acid fluid exudes, drop by drop, frommillions of little tubes in the innersurface of the stomach, until finallythe surface is moistened in every part,and the fluid begins to mingle with thefood. This fluid is termed the gastricjuice. 25. The gastric juice dissolves cer-tain articles of food, especially thosebelonging to the albuminoid class. Thissolvent power is due to its peculiar in-gredient, pepsin ; in digestion, this sub-stance acts like a ferment—that is, itinduces changes in the food simply byits presence, but does not itself undergochange. The acidity
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Keywords: ., bookcentury1800, bookdecade1, booksubjectphysiology, bookyear1887
