title: Fine structure of internodal pathways.
mesh_terms: D000818:Animals; D016275:Atrial Function; D004285:Dogs; D004594:Electrophysiology; D006325:Heart Atria / Q000166:cytology / Q000294:innervation; D006329:Heart Conduction System / Q000033:anatomy & histology* / Q000166:cytology / Q000502:physiology; D006801:Humans