Anatomy of the septomarginal trabecula in Landrace pig hearts

Morphology of septomarginal trabeculae in Hatay mountain gazelle (Gazella gazella)

This study was conducted to reveal the anatomical and histological features of left and right septomarginal trabeculae in the heart of the Hatay mountain gazelle. In the study, two female and two male adult Hatay mountain gazelle hearts were used. For this purpose, the materials detected in 10% formaldehyde solution were stained with Crossman's modified triple staining technique and examined under a light microscope after anatomical examinations and measurements were made. The presence of trabeculae in both ventricles was demonstrated. While the number of septomarginal trabeculae was 1 in each of the samples in the right ventricle, it was determined that it was 2 in each of three hearts and 3 in one heart in the left ventricle. It was observed that the right trabeculae were unbranched and fleshy, while the left trabeculae were filamentous and mostly branched. The lengths and thicknesses of the right trabeculae were measured 12-17 mm and 3-4 mm and the lengths and thicknesses of the left trabeculae were measured 6-15 mm and 0.5-1 mm. In the histological examination of both trabeculae, connective tissue, Purkinje fibres and blood vessels were observed, in addition, it was detected that the right trabeculae had myocardial fibres. Few capillaries were found in the left trabecula, while both more capillaries and blood vessels were found in the right trabeculae.

Histological and anatomical variations of septomarginal trabecula in bovine hearts

The use of hearts from different animals as models in the experimental pharmacology and surgical clinic has led, in recent years, to an increase on interest of research with this organ. The heart's conducting system, from the septomarginal trabecula, presents several variations, which generates numerous controversies in the literature. So, the objective of the present study is to analyse the morphology of the septomarginal trabecula of bovine hearts, identifying possible macro- and microscopic variations. Thirty-four bovine hearts were analysed. Each trabecula was analysed macroscopically to obtain an anatomical description and measurements of its length and thickness. For histological and morphometric analysis, the samples were fixed in Bouin's solution and then subjected to histological processing. In all the analysed bovine hearts, the septomarginal trabecula presented itself as a smooth, tubular meaty structure of muscular consistency, with variable length and diameter. The anatomical variations observed included a trabecula with forked marginal fixation, and single septal fixation, in addition to a trabecula with extremely reduced or excessively thick caliber. The septomarginal trabecula consists of cardiac muscle fibres, connective tissue, vascular tissue and conduction myofibrils or Purkinje fibres. In the samples of smaller thicknesses, there was a predominance of connective tissue and scarce cardiac muscle tissue, whereas in the thicker samples the predominance was of cardiac striated muscle tissue. Therefore, there are significant macro- and microscopic differences between the bovine septomarginal trabecula concerning their diameter and constituent tissue, and that can lead to possible changes in cardiac physiology.

Morphology of moderator bands (septomarginal trabecula) in porcine heart ventricles

The morphology of moderator bands in both heart ventricular cavities was examined on macro- and microscopic levels in 14 six-month-old Landrace pigs. One transverse moderator band, measuring 2.9 ± 0.6 mm in diameter, was located between the septum and the free wall of the right ventricular cavity. On cross-section, clumps of conductive cells were found at the periphery of the moderator band and in its central part around the blood vessels. Large amounts of muscle fibres were identified. The left ventricular cavity contained moderator bands in the form of thin cords, measuring 1.05 ± 0.09 mm in diameter and located mostly between the interventricular septum and the papillary muscles. Conductive tissue was represented by clumps of Purkinje cells, surrounded by myocardial fibres. The proportion of conductive cells and muscle fibres in the moderator bands was approximately the same. Owing to different amounts of conductive cells and muscle fibres in the bands, we assume that moderator bands in the right and left ventricles play different primary functional roles. Our results were compared with previous data on pigs and other ungulate animal species.