Drake C J, Jacobson A G
Department of Zoology, University of Texas, Austin 78712.
Anat Rec. 1988 Dec;222(4):391-400. doi: 10.1002/ar.1092220411.
Scanning electron microscopy was used to study the morphogenesis of the primitive embryonic chick heart (stage 5 late primitive streak through stage 9+). Components of the developing heart (myocardium, endocardial endothelium, and extracellular matrix) were viewed from the ventral surface after removal of the endoderm. The myocardial component of the heart can first be seen by light microscopy at stage 5 as two darker oval-shaped areas located on either side of the embryonic axis in the cranial region of the embryo. Scanning electron microscopy demonstrates that as early as stage 6 an area of extracellular matrix, enriched in comparison to more lateral and medial splanchnic mesoderm, can be identified ventral to the myocardial primordium. As heart formation progressed we observed primordial endothelial elements in the splanchnic mesoderm lateral to the myocardial primordia. By late stage 7 these lateral primordial elements had anastomosed into small, loose plexuses. This process of anastomosis progressed rapidly, and by stage 8 the entire cranial surface of the myocardial primordium was covered with vascular plexuses. By late stage 8 the progressive fusion of these plexuses resulted in the formation of large multiple tubular elements near the midline. More medially the fusion of tubular elements resulted in a continuous endothelial sheet at the midline.
扫描电子显微镜用于研究原始鸡胚心脏（第5期晚期原条至第9 +期）的形态发生。去除内胚层后，从腹面观察发育中心脏的组成部分（心肌、心内膜内皮和细胞外基质）。心脏的心肌成分在第5期通过光学显微镜首次可见，为位于胚胎颅区胚胎轴两侧的两个较暗的椭圆形区域。扫描电子显微镜显示，早在第6期，与更外侧和内侧的脏壁中胚层相比富含细胞外基质的区域可在心肌原基腹侧被识别。随着心脏形成的进展，我们在心肌原基外侧的脏壁中胚层观察到原始内皮成分。到第7期末，这些外侧的原始成分已吻合形成小而松散的丛状结构。这种吻合过程迅速进展，到第8期时，心肌原基的整个颅面被血管丛覆盖。到第8期末，这些丛状结构的逐渐融合导致在中线附近形成大的多个管状结构。在更内侧，管状结构的融合在中线处形成连续的内皮片。
