American journal of physiology (1898) (14802956733)

Identifier: americanjourna33ameruoft (find matches)

Title: American journal of physiology

Year: 1898 (1890s)

Authors: American Physiological Society (1887- ) American Physiological Society (1887- ). Abstracts of papers presented at the fall meeting American Physiological Society (1887- ). Proceedings

Subjects: Physiology Physiology

Publisher: (Bethesda, Md., etc.) American Physiological Society (etc.)

Contributing Library: Gerstein - University of Toronto

Digitizing Sponsor: University of Toronto

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nded curve) so that the pulse pressure is not greatlyreduced. In the third wave, however, occurring at the heightof inspiration, the systolic pressure is markedly lower and thepulse pressure is much reduced. Corresponding changes in theheight of the carotid curve take place. The contour of the in-spiratory pressure wave differs from that of expiration. In The Pressure Curve in the Pulmonary Artery 9 the former the auricular wave is less prominent but the ampli-tude of the pulmonary vibration (d — e—f) becomes much greater.The time relations remain unchanged. The primary upstroke(gh) also becomes larger and sharper in its rebound and afterits completion returns more rapidly to the top. The systolicsummit (Fig. 4, k) which was smoothly rounded in expiration,approximates a short ascending or horizontal plateau whichindicates a resistance more readily overcome. Everything, in short, indicates a reduced tension or loweredelasticity coefhcient of the vessels during inspiration, allowing

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Figure 5. (Two thirds the original size.) Three waves of pulmonary arterial pressureafter saline infusion (lower record). First, during expiration; second and third,during inspiration. Carotid pressure (upper record). greater vibrations to take place. This is even more clearlyshown in other records where two primary vibrations occurduring inspiration and the second is damped out during theexpiratory phase (Fig. 5). Influence of saline infusion. — In the experiments abovedescribed the right auricular pressure during expiration wassKghtly above intrathoracic. In experiment C20, IV, e.g., fromwhich the waves of Fig. 4 were taken, the right auricular pres-sure was 14 mm. of water during expiration and — 15 mm.during inspiration, pressures which may be regarded normal,inasmuch as they agree favorably with pressures found in un- lo Carl J. Wiggers aesthetized animals.^ In order to study the nature of the pres-sure changes when the right auricular pressure was beyonddoubt above that whic

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1898

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