A manual of personal hygiene - proper living upon a physiological basis (1917) (14577385690)

Identifier: manualofpersonal00pyle (find matches)
Title: A manual of personal hygiene : proper living upon a physiological basis
Year: 1917 (1910s)
Authors: Pyle, Walter L. (Walter Lytle), 1871-1921
Subjects: Hygiene
Publisher: Philadelphia : W.B. Saunders Co.
Contributing Library: University of Connecticut Libraries
Digitizing Sponsor: University of Connecticut Libraries



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gh admixture of them withthe saliva, depends in no small degree the comfortwith which the gastric digestion is carried out.Starchy foods in particular require the effect of theptyalin, a constituent of the saliva, by the action ofwhich the starch, especially when thoroughly cooked,is converted into maltose. The saliva escapes into themouth from three separate sets of salivary glands—the parotid at the angle of the jaw, the submaxil-lary along the side of the tongue, and the sublingualunder the tongue. The mouth is further moistenedby the secretion of the mucous membrane with whichit is lined. The salivary secretion is excited by thepresence of foreign bodies in the mouth, but especi-ally by food. The action of the glands is controlled 9 lO THE DIGESTIVE APPARATUS. by the nervous system, and the effect of the highernervous centers upon their activity may be instancedin the free flow of saliva that follows the odor of cer- Nose Sahvarv ^ glands C^ f Trachea 1 1 Salivary (Parotid)gland
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Duoden Large intes-tine Small intestine ,, ^^ Rectum Vermiform appendi Fig. I.—General scheme of the digestive tract, with the chief glands open-ing into it. tain substances, and the sight, or even thought, ofothers. The saliva is slightly alkaline in reaction,and its activity differs in different individuals. THE STOMACH. II The conversion of starch into maltose by ptyalin isdiminished in the presence of a slightly acid medium,and ceases in a free acid medium. If the saliva is di-luted by water or other fluids, its activity is correspond-ingly diminished. Therefore foods should only beswallowed after they are thoroughly disintegrated bythe teeth and sufficiently liquefied by the saliva topass easily through the esophagus without the assist-ance of drink. The stomach is a muscular sac, lying for the mostpart on the left side of the body and under the ribs.Its entrance, at the termination of the esophagus, iscalled the cardia, and is guarded by an increase inthe circular muscle-fibermanualofpersonal00pyle