. The biology of marine animals. Marine animals; Physiology, Comparative. isec Fig. Refractory Period and Recovery of Excitability in the Heart of Torpedo o eel lata Effect of a strong induction shock on the ventricle at different intervals after the occurrence of an auricular contraction. Exact moment of stimulation is shown by the black spots on the tracings. (From Mines, 1913.) which excitability gradually returns (Fig. ). At the end of systole and throughout most of diastole an interpolated stimulus evokes a contraction of submaximal height (relative refractory period); recovery be
. The biology of marine animals. Marine animals; Physiology, Comparative. isec Fig. Refractory Period and Recovery of Excitability in the Heart of Torpedo o eel lata Effect of a strong induction shock on the ventricle at different intervals after the occurrence of an auricular contraction. Exact moment of stimulation is shown by the black spots on the tracings. (From Mines, 1913.) which excitability gradually returns (Fig. ). At the end of systole and throughout most of diastole an interpolated stimulus evokes a contraction of submaximal height (relative refractory period); recovery becomes com- plete by the end of diastole. Any extra contraction interposed between two normal contractions is followed by a compensatory pause longer than a normal diastolic pause. The long absolute and relative refractory periods preclude tetanization of heart muscle. When quiescent strips of vertebrate heart muscle are stimulated by repeated shocks at suitable intervals (longer than the refractory period), they respond by single contractions of increas- ing magnitude, an effect known as staircase. According to Starling's law of the heart the strength of contraction is dependent on its degree of distension. This is an effect common to all muscle by which the force of contraction increases with stretching, up to some maximal value. By this means the heart adapts itself to a given load. The mechanics of cardiac output in several freshwater teleosts have been investigated by Hart (58). The blood pressure rises with increase in rate of. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Nicol, J. A. Colin (Joseph Arthur Colin), 1915-. New York, Interscience Publishers
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Keywords: ., bookcentury1900, booksubjectmarineanimals, booksubjectphysiology
