Moderator Bands (Trabecula septomarginalis) of Mature Buffalo (Bos bubalis L.) with Special Emphasis on the Structure and Distribution of the Purkinje Cardiomyocytes: Histological and Histochemical

Wael Am Ghonimi

doi:10.4172/2168-9296.1000165

Abstract

Ten hearts of mature healthy Buffalo (Bos bubalis L.) were employed to investigate the histological and histochemical structures of the moderator bands. Hearts were gently dissected and the moderator bands were collected. The specimens were processed histologically and subjected to different stains. Grossly, the moderator band (Septomarginal trabeculae) was a single muscular band that was found only in the right ventricle of the buffalo heart. It extended from the interventricular septum to the free ventricular wall especially at the base of the papillary muscle, crossing and passing through the ventricular cavity. Histologically, the moderator band was invested in a dense capsule of connective tissue, endocardium that is mainly consisting of three layers; the endothelial layer of simple squamous epithelium, subendothelial layer of loose connective tissue and the subendocardial layer that connects the endocardium with myocardium. Internally, about 4/5 of the core, myocardium is of the cardiac muscle fibers that arranged in bundles of one direction while only about 1/5 is lodged by purkinje cardiomyocytes that were arranged in bundles distributing mainly in two areas within the moderator band; the subendocardial layer beneath the subendothelial connective tissue and myocardium in between the cardiac myocytes bundles. Centrally, a medium-sized artery of thick wall and a very distinct internal elastic lamina was observed running at the center of the band myocardium and is surrounded with the cardiac myocytes bundles.

Highlights

The right ventricle has one muscular moderator band which extends from the interventricular septum to the opposite ventricular wall especially at the papillary muscle, crossing and passing through the ventricular cavity and appearing as a fleshy and muscular in its consistency (Figure 1-3)
The moderator band is observed consisting of two major compartments; the central is myocardium and the peripheral is endocardium which acts as the moderator band capsule (Figure 5)
The present investigation clarified that the moderator band (Septomarginal trabeculae) of the buffalo heart is a single muscular band that extends from the interventricular septum to the opposite right ventricular wall especially at the papillary muscle, crossing and passing through the ventricular cavity and appearing as a fleshy and muscular in its consistency

Summary

Introduction

Single and branched fibromuscular strand, moderator band was described in the camel right ventricle extending from the interventricular septum to the ventricular free wall at the base of the papillary muscle, passing through the ventricular cavity and appeared fleshy and muscular in its consistency [1,2,3].In other works, Lorenz and Hunigen [4], Lorenz [5], Lorenz and Guski [6], Crick et al [7] and Rocha et al [8] have shown that the muscle bundle in the septomarginal trabecula of pig hearts is generally a resistant crest that goes from the lower part of the septum to the lower part of the anterior papillary muscle.Depreux et al [9] described that the size and shape of the septomarginal trabecula depend on the size of the heart and the age of the animal. Single and branched fibromuscular strand, moderator band was described in the camel right ventricle extending from the interventricular septum to the ventricular free wall at the base of the papillary muscle, passing through the ventricular cavity and appeared fleshy and muscular in its consistency [1,2,3]. Hsu and Du [10] assumed that the different morphological variations of the moderator bands have been described as congenital heart anomalies in the porcine right ventricle (including two parallel bands merging in the middle part or a band that does not cross the ventricular cavity, but connects the parietal papillary muscle with a deformed trabecula). Bojsen-Moller and Tranum-Jensen [11] claimed that the right bundle branch of the conducting system of the heart passes down the interventricular septum and continues by way of the septomarginal trabecula to the base of the anterior papillary muscle. Conductive cells were located in the central part in bands, which did not contain muscle fibres

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