File:A text-book of physiology - for medical students and physicians (1916) (14767981214).jpg

Identifier: textbookofphysio1916howe (find matches)
Title: A text-book of physiology : for medical students and physicians
Year: 1916 (1910s)
Authors: Howell, William H. (William Henry), 1860-1945
Subjects: Physiology Medicine
Publisher: Philadelphia and London : W. B. Saunders Company
Contributing Library: Yale University, Cushing/Whitney Medical Library
Digitizing Sponsor: Open Knowledge Commons and Yale University, Cushing/Whitney Medical Library

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Fig. 266.—Figure of Mareys pneumograph.—(Verdin.) The instrument consists ofa tambour it), mounted on a flexible metal plate (p). By means of the bands c and cthe metal plate is tied to the chest. Any increase or decrease in the size of the chest willthen affect the tambour by the lever arrangement shown in the figure. These changes inthe tambour are transmitted through the tube r as pressure changes in the contained airto a second tambour (not shown in the figure) which records them upon a smoked drum. does not record the pause, if any, at the end of inspiration or ex-piration. A modification of this method that permits an accuraterecord of the amplitude and duration of the movements consists inconnecting the trachea or nostrils with a large bottle of air. Theanimal breathes into and out of the bottle, and the corresponding
Text Appearing After Image:
Fig. 267.—Curve of normal respiratory movements.—(Marey.) Curve A, full line,represents the movements when the respiration is entirely normal. Downstroke, inspira-tion; upstroke, expiration. CurveO, dotted line, represents the increased amplitude of themovements, slight dyspnea, caused by breathing through a narrow tube. variations in pressure are recorded by a tambour also connectedwith the interior of the bottle. (3) Methods in which the changeof pressure in the thoracic cavity is recorded. This end may bereached by inserting a cannula into the thoracic wall so that itsopening lies in the pleural cavity, or, more simply, a catheter orsound connected at the other end to a tambour may be passed down EXTERNAL RESPIRATION AND RESPIRATORY MOVEMENTS. 653 the esophagus until its end lies in the intrathoracic portion.Variations in pressure in the mediastinal space synchronous withthe respiratory movements affect the esophagus and through itthe sound. (4) Methods in which the movements o

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