The sensory and motor disorders of the heart : their nature and treatment / by Alexander Morison.

  • Morison, Alexander (Alexander Blackhall), 1850-1927.
Date:
1914
Catalogue details

Licence: Public Domain Mark

Credit: The sensory and motor disorders of the heart : their nature and treatment / by Alexander Morison. Source: Wellcome Collection.

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    views of the nerveless automatism of these structures should have been regarded as possible. This innervation, to which I shall have to refer in greater detail, has now been satis¬ factorily established, and some other facts which I shall mention render it probable that the conception, in any case of the auriculo-ventricular bundle, as a part of the original cardiac tube, may also have to be abandoned. The sinu-auricular node, situated, as its name implies, between the sinus as represented by the superior and inferior venae cavae and the auricular appendix, is neither so elaborate nor extensive a structure as the auriculo-ventricular node and tract. It consists of a muscular tissue in which the nuclei are large, and the cells so approximated as to make them appear more numerous than in an equal area of ordinary muscular tissue. The striae of the fibres are indistinctly marked, it is definitely subepicardial in position, and pro¬ cesses from it pass into the auricle in the interstitial spaces between the ordinary muscular fibres; while some, likewise, pass upwards into the musculature of the termination of the superior vena cava. If the fibres which Wenckebach describes1 as uniting this node to the ordinary auricular muscle be those I have mentioned as issuing from the node into the intermuscular spaces of the adjacent auricle, I can confirm his observa¬ tion ; but, as I have stated, they likewise penetrate the caval musculature. Some have ascribed a much more extensive range to the fibres of the sinu-auricular node. Thorel2 establishes a con¬ nection between the sinu-auricular and auriculo-ventricular nodes by way of the coronary veins and coronary sinus. It is difficult in the normal adult mammalian heart to escape the impression that the node of Tawara and the bundle of His are related to the structures at the mouth of the coronary sinus; but in the persistent embryonism of the case of foramen primum which I have described in the Journal of Anatomy and Physiology for July, 1913, I have been able to show that the node of Tawara has no connection whatever 1 Archiv/. Physiol1907. 2 Munchen. Med. WochenschNo. 4, 1910.