Contribution to the study of the sinu-atrial node in Sus scrofa domestica. I. Topography. II. Histology. III. Arterial bloody supply

Abstract

This study was based upon the exam of 68 hearts of underbred adult swine — 36 male and 32 female. I t allowed the following conclusions:1 — the sinus node tissue is located at the sulcus terminalis and half the dihedron caval atrial angle near it ; 2 — the morphological characteristics of the specialized cells of the node, as well as the different types of fibers that compose the vascular conjunctive stroma are stressed; glycogenis abundant in the cytoplasm of the specialized cells of the node.3 — the sinu-atrial node is supplied by the arteria coronaria dextra in 55 pieces (91.7% ± 3.6) — 35 times (58.3% ± 6.Jt) through the ramus proximalis atrii dextri plus the ramus intermedius atrii dextri 22 times, and the ramus distalis atrii dextri 13 times; 18 times by the ramus proximalis atriidextri (30.0% ± 5 .9 ) ; and twice by the ramus intermedius atrii dextri(3.3 ± 2.3) 4 — the nodal tissue region depends partly (3 times — 5.0% ±2.8) or exclusively (twice — 3.3% ± 2.3) on the ramus proximalis atrii sinistri; in the first case there appear also the ramus intermedius atriidextri (twice — 3.3% ± 2 .3 ) ; and the ramus distalis atrii dextri (once —1.7% ± 1.7); 5 — there were nine anastomoses between the vessels supplying the sinu-atrial node in 8 of the hearts (26.7% ± 8 .1 ) ; 6 — there were no significant differences between male and. female concerning the different types of arterial supply.