Therapeutics of the circulation / by Sir Lauder Brunton.

  • Lauder Brunton
Date:
1914
Catalogue details

Licence: Public Domain Mark

Credit: Therapeutics of the circulation / by Sir Lauder Brunton. Source: Wellcome Collection.

    86/568 page 58
    Pacemaker of the Heart.—The S-A node is supposed to be more sensitive than the A-V node, and usually to act as the pacemaker of the heart.27 Nodal Rhythm.—When the S-A node fails to act the A-V node is capable of initiating a rhythm of its own, just as the upper part of the frog’s ventricle does when entirely separated jT Fig. 20.—Purkinje’s fibres from a sheep’s heart, n, Nuclei; c, proto¬ plasm ; /, striated muscular substance. (After Ranvier, Legons d’Anatomic Generale sur le Systdme Musculaire (Paris : Delahaye & Co., 1880), p. 300.) from the auricle (p. 30). This has been called by Mackenzie, Nodal Rhythm.28 Ventricular contractions due to stimuli arising from the usual place, viz. the S-A node, have been termed nomotopic, and those arising from other places ectopic.20 Heart-block.—The same phenomena that Gaskell observed (p. 32) when the auriculo- ventricular groove in the frog’s heart was com¬ pressed by a clamp have been found to occur
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