Stereological Cell Morphometry In Right Atrium Myocardium Of Primates

The mechanism by which the cardiac impulse is propagated in normal hearts from its origin in the sinus node to the atrio-ventricular node has not been agreed on fully. We studied the "internodal posterior tract" through the crista terminalis by light microscopy and stereological morphometry. The hearts of 12 Papio cynocephalus were perfused , after sacrifice,with phosphate-buffered formol saline. The regions of the crista terminalis (CT), interatrial septum (IAS), atrioventricular bundle (AVB) and interventricular septum (IVS) were cut off and embedded in paraplast and sectioned (10 4m). The multipurpose test system M 42 was superimposed over the photomicrographs (1,890 points test, ESR = 2%) to the stereological computing. The quantitative results show that the cells from CT were more closely relationed with IAS cells than others cells (IVS and AVB cells). This results are not a morphological evidence to establish the specificity of the "internodal posterior tract". The cellular arrangement and anatomical variation in CT myocardium is very important.