Estudo morfofuncional sobre o seio coronario no homem adulto

AUTOR(ES)
DATA DE PUBLICAÇÃO

1987

RESUMO

The mechanisms yhich contribute to the closing of the ostium of the coronary sinus and that impede the venous reflux during the atrial systole are not fully understood. The arrangement of the fibrous elements which make up the wall of the sinus is also unknown. The purpose of this paper is to present a morpho-functional analysis at a mesoscopic level, of the coronary sinus, considering, in an integrated way, the arrangement of the muscular, collagen and elastic elements which compose the wall of the vessel, as well as the participation of of these elements in the opening and closing mechanism of the ostium in the right atrial cavity. To carry out our proposal 24 adult cadaver hearts were analyzed fay means of fine dissection, with the aid of a magnifying glass and of stereo microscopy, of histological technics and of thick cuttings as yell as polarized light microscopy. Based on the results, we believe we are able to draw the following conclusions from our study; the tunica media of the coronary sinus wall is entirely composed of bundles of muscle fibers similar to those of the myocardium; these bundles originate mainly in the wall of the left atrium; the muscular bundles are found in the form of elongated spirals that come together on two planes; the muscular bundles of the ostium of the coronary sinus are predominantly semicircular creating a type of sphincter; the collagenous fiber bundles form a network of elongated mesh in both the tunica intima and the external coat; in the tunica media, the fibers are found between the muscular bundles; the elastic fibers also form an elongated meshwork and, in the media, constitute almost concentric layers which envelop the muscular bundles; the coronary sinus is almost completely surrounded in a varying quantity of adipose tissue. Consequently, supported by our results, we can suggest that during an atrial systole the ostium of the coronary sinus closes by the contraction of its surrounding muscular bundles, complemented by the action of the Thebesius valve thus impeding the reflux of blood. Afterward, by the contraction of the spiral fibers in its wall, an expansion of the lumen and a shortening of the organ occurs after which another contraction of the fibers, now with an annulate disposition, occurs resulting in a decrease in the size of the lumen of the coronary sinus. The collagenous fibers present in the wall of the coronary sinus prevent excessive distension, while the elastic component is responsible for maintaining a certain degree of expandability during increase of blood pressure as well as helping in the sphincteric phase of the musculature

ASSUNTO(S)

oclusões arteriais aorta anatomia humana

ACESSO AO ARTIGO

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