File:American journal of physiology (1898) (14782328015).jpg

Identifier: americanjourn01ameruoft (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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ion. Which of these factors has the upper hand? Does thecheck which the circulation through the walls sustains during systolediminish the total volume of blood passing through the wall perminute, or is the lessening more than made up by the favorable fac-tors — the emptying of the intramural vessels and their easier re-filling? The experiments next to be described afford a partial answerto this question. In February, 1896, while studying with Messrs. Magrath and Ken-nedy the relation of the volume of the coronary circulation to thefrequency and force of the ventricular contraction in the isolatedheart of the cat, I observed that the heart took more blood throughthe coronary arteries from a reservoir under constant pressure whencontracting than when at rest. The same observation was madeagain, later in that year, when at work with Miss Hyde on the effectof the distention of the ventricle on the flow of blood through thewalls of the heart. The fact is very well demonstrated by Fig. 4.
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miiiiiUmiiaiiiauuijiMiliMiiljjiijiliMi^MW^^ Fig. 4. Showing the increase in the volume of the coronary circulation consequent onan increase in the force of ventricular contraction. The uppermost tracing is thepressure in the left ventricle of the isolated heart of the cat, recorded by a Hlirthlemanometer ; the next is the time, in seconds ; and the lowermost is the record of thedrops of blood flowing through the coronary vessels. The arrow points to the dis-tention of the ventricle, which shortly calls forth beats of greater force. From anexperiment performed with Miss I. II. Hyde. In this experiment the extirpated heart of a cat was fed with warmdefibrinated cats blood from a reservoir at constant pressure througha cannula in the ascending aorta, all the branches of that vessel ex-cept the coronary arteries having previously been tied. The blood Influence of Heart-beat on Flow through Heart-Walls, 159 passed from the coronary artery into the right ventricle, and thencethrough a glass

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