Elementary anatomy, physiology and hygiene for higher grammar grades . submaxillary, situatedunder the jaw; and the sublingual, upder each side of thetongue. These glands make or secrete the saliva andgive it out when stimulated by the presence of food in themouth, or even by the thought of food. The pharynx is supplied with, twodoors which preventthe food from gettinginto the wrong pas-sages. In order thatthe food may not gointo the nasal passagethe uvula and softpalate turn back dur-ing the process ofswallowing and coverthe opening ; andthat it may not gointo the air tube, alittle guard, the
Elementary anatomy, physiology and hygiene for higher grammar grades . submaxillary, situatedunder the jaw; and the sublingual, upder each side of thetongue. These glands make or secrete the saliva andgive it out when stimulated by the presence of food in themouth, or even by the thought of food. The pharynx is supplied with, twodoors which preventthe food from gettinginto the wrong pas-sages. In order thatthe food may not gointo the nasal passagethe uvula and softpalate turn back dur-ing the process ofswallowing and coverthe opening ; andthat it may not gointo the air tube, alittle guard, the epi-glottis, protects theopening of the airpassage. This is donevery quickly, for dur-ing the process ofswallowing one can-not take breath. Onedoes occasionally try to breathe and swallow at the sametime, with the result of getting food into the windpipe,causing violent coughing until i^ is expelled. Theesophagus is a long tube which has a soft mucous liningand a muscular coat of circular bajids. In forcing thefood along the esophagus the muscular bands do not con-. FiG. 23. — The jaws and the teeth; 1,2, incisors;3, cauine ; 4, 5, bicuspids; 6, 7, S, molars;ffl, vein; &, artery; c, nerve; (2, vein, artery,and nerve. [From Johownot and Bonton.] NUTRITION 93 passage tract all at once, but in succession, beginning at thepharynx. The first contracts and makes thesmaller, and thus pushesthe food on to be con-tracted upon by the nextband. This motion iscalled peristaltic same kind of motioncarries the food along thewhole extent of the ali-mentary canal. 7. OF THESYSTEM
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