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Mechanism of dextral looping of the embryonic heart

1970; Elsevier BV; Volume: 25; Issue: 3 Linguagem: Inglês

10.1016/s0002-9149(70)80002-9

1879-1913

Helge Stalsberg,

Connective tissue disorders research

A number of developmental features are discussed as possible factors in the mechanism of dextral looping of the embryonic heart. These include features of early asymmetry of the embryo, skewness and right dislocation of the plane in which the heart primordia fuse, mechanical factors acting upon the heart from movements of adjacent tissues, differential elongation of pericardial cavity and heart tube, caudal movement of the whole heart, mechanism of cell redistribution in the heart mesoderm, different patterns of differentiation in the two heart rudiments, asymmetries in the number of cells contributed to rostral and caudal parts of the conoventricular loop from the two heart primordia, and asymmetry in the initiation of the heartbeat. It is suggested that several factors with overlapping effects may cooperate in the production of dextral looping, thus compensating for developmental instability resulting from individual variation of single factors. A number of developmental features are discussed as possible factors in the mechanism of dextral looping of the embryonic heart. These include features of early asymmetry of the embryo, skewness and right dislocation of the plane in which the heart primordia fuse, mechanical factors acting upon the heart from movements of adjacent tissues, differential elongation of pericardial cavity and heart tube, caudal movement of the whole heart, mechanism of cell redistribution in the heart mesoderm, different patterns of differentiation in the two heart rudiments, asymmetries in the number of cells contributed to rostral and caudal parts of the conoventricular loop from the two heart primordia, and asymmetry in the initiation of the heartbeat. It is suggested that several factors with overlapping effects may cooperate in the production of dextral looping, thus compensating for developmental instability resulting from individual variation of single factors.