On the inervation of the heart, with especial reference to the heart of the tortoise.

  • Gaskell, Walter Holbrook, 1847-1914.
Date:
1883
Catalogue details

Licence: Public Domain Mark

Credit: On the inervation of the heart, with especial reference to the heart of the tortoise. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

    50/104
    regular increase in tlie rate of tliese V. A. contractions thus brought to light is exactly similar to the development of the rhythm in the isolated ventricle or auricle and shows that such a development was going on during the whole time of the experiment. When the ventricle was isolated by clamping and section it was found to be beating with great regularity at the same rate as during the last vagus stimulation in curve v. In tliese cases the independent rhythm of the ventricle was at no time quicker than the rhythm of the sinus, and therefore was entirely con- cealed until the sinus rhythm was brought to a standstill by the action of the vagus nerve. If however after section of the coronary veins the rhythm of the sinus be artificially slowed by the application of cold salt solution, while that of the ventricle is at the same time developed and quickened by sending a warm blood solution through its coronary vessels, then as soon as the ventricular rhythm reaches a rate quicker than that of the sinus, the latter is concealed by the quicker ventricular rhythm, and we have the phenomenon of a regularly beating heart, in which every contraction starts from the ventricle and passes through the auricle to the sinus. Upon then cutting away the ventricle, the slow sinus rhythm is immediately manifested. Thus the automatic sinus rhythm can be obscured by a quicker ventricular rhythm just as the automatic ventricular rhythm can be obscured by a quicker sinus rhythm. On tlie action of the cardiac nerves upon the force of the contractions of the auricle, ventricle, and sinus. According to the principles previously laid down, we have already examined the action of the cardiac nerves upon one of the properties of the cardiac muscular tissue, viz. the property of rhythm, and have therefore confined our attention exclusively to the relation of the cardiac nerves with those particular portions of the cardiac muscle in which the rhythmical power has been preeminently developed. We have now to consider seriatim the action of the nerves upon the other properties of the cardiac muscular tissues, and in the first place then- action upon the contraction force. The movements of the upper and lower levers register the contractions of the whole auricle and ventricle, i.e. the con- tractions of the reticulated fibres of these two cavities which form by far the largest mass of muscular fibres. In considering, then, the valua- tions of contraction force produced by nervous action, we are essentially considering the relations of the cardiac nerves, in one respect at all events, to a group of muscle fibres different in arrangement and charac- : differ ►T>1< ‘fL od * the # T - Derveas*el it V**- , ses tie ventricular« The of ihj ti® of the cardiac mi raries inversely as th final m' tag, 1? of its strict lntaooat] l0I1;t] He l»it thi % the;