The morphogenesis of the four-chambered heart is one of the most intricate processes in higher vertebrate embryology, which involves a program of gene expression, differential growth, spatial organization, and cell movement. Since diffusion of nutrients from the surrounding tissues, which nourishes the rapidly growing embryo in its earliest stages, soon becomes insufficient, the embryonic cardiovascular system is the first functioning organ to appear. Thus, a primitive but functioning circulation with a beating heart is already accomplished during the beginning of the fourth week of development. During development, the primitive single-circuited tubular heart must evolve into a four-chambered double-circuited structure, while it is already committed to its lifelong task, i.e. maintaining circulation. This requires profound and complex remodeling, which is difficult to comprehend and makes great demands on one’s spatial insight. With the advent of molecular technology a new era in cardiac embryonic research has begun and the mechanisms involved in the sequential processes of cardiac development are now starting to become unraveled.
KeywordsChicken Embryo Heart Tube Pericardial Cavity Embryonic Disc Vitellinous Vein
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