Cardiac Looping and Formation of the Heart Regions in Japanese Quail Embryo (Coturnix coturnix).

Abstract

In this study the morphological changes of the de- veloping 100 heart tubes and formation of the heart regions in Quail embryos were examined from the first till the fourth day of development. Special dis- secting tools were prepared and used for dissecting the embryos, normal histological techniques for the histological study were adopted and the binocular stereomicroscope, inverted microscope and light microscopes were used. The study proved that the cardiac looping of the Quail embryos, like that of the chick embryos, took 3 stages but occurred earlier: the straight heart tube of the quail was formed at about 24-26 hours of the development. The stage of dextral looping took the period between 26 and 40 hours of the develop- ment. The Transformation of the C-shaped heart loop into the S-shaped heart loop started at 39-40 hours and finished at 52-55 hours of the development. The process of cardiac looping was accompanied by formation of the heart regions and followed by posi- tional changes and disappearance of the Bulbus cordis. The results obtained are important for the embryolo- gists using the quail-chick chimera system in the development. Both quail and chick embryos used in this system must be at the comparable not the same ages of the devel- opment to avoid the malformations resulted from using the miss ages.