. Text-book of anatomy and physiology for nurses. ophageal orificeguarded by the sphincter of the cardia;at the right is the pyloric orifice,guarded by the sphincter of thepylorus or gate-keeper. The coats or tunics of the stom-ach are four in number—mucous, sub-mucous, muscular, and serous. The mucous layer, or mucosa, isthe innermost layer. It is pink incolor but becomes bright red when food is present, from theincreased blood-supply necessary for digestion. It lies in folds, orrugce, running from one extremity to the other—the longitudinalfolds. This layer contains the gastric glands which
. Text-book of anatomy and physiology for nurses. ophageal orificeguarded by the sphincter of the cardia;at the right is the pyloric orifice,guarded by the sphincter of thepylorus or gate-keeper. The coats or tunics of the stom-ach are four in number—mucous, sub-mucous, muscular, and serous. The mucous layer, or mucosa, isthe innermost layer. It is pink incolor but becomes bright red when food is present, from theincreased blood-supply necessary for digestion. It lies in folds, orrugce, running from one extremity to the other—the longitudinalfolds. This layer contains the gastric glands which secrete thegastric juice and pour it through their ducts into the stomach. The gastric glands are tubular in form, microscopic in size, andvery numerous (their number is estimated at 5,000,000). Theydiffer markedly in the two portions of the stomach. The cardiacglands secrete the digestive ferments, pepsin and rennin, whilethe pyloric glands secrete mucus also (Fig. 100). The reaction of the gastric juice is acid (owing to hydrochloricacid).. v;^- Fig. 100.—Section of PyloricGlands from Human Mouth of gland leading intolong, wide duct (6), into whichopen the terminal di\isions. tissue of the mucosa(after Piersol). THE STOiMACH. 129 The suhmucosa is a network of connective tissue next to themucous coat. It bears fine vessels, nerves and lymphatics, andconnects the mucous and muscular tunics together loosely, so thatwhen the stomach is distended the longitudinal folds simply disappear,without injury to the mucous membrane. The muscular coat (or tunic) comprises three layers of non-striatedmuscle: internal, middle and external. The internal layer consistsof oblique fibers (it is a thin layer and is mostly confined to thecardiac portion). The middle layer is a complete layer of circularfibers. They are most numerous at the extremities of the stomach,where they form two ring-shaped bundles. One is the sphincter ofthe cardia, surrounding the lower end o
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