Although the laboratory exercises in ABLE proceedings volumes have been tested and due consideration has been given to safety, individuals performing these exercises must assume all responsibilities for risk. This laboratory experiment is designed to introduce students to the developmental process of the vertebrate heart using the chicken embryo as a model system. Simultaneously, the students are also exposed to the physiology of embryonic blood flow and the electrical circuitry of the developing heart. Described herein is a review of the chicken heart development and a summary of our basic protocol. The heart of the chicken embryo develops from the fusion of paired precardiac mesodermal tubes located on either side of the developing foregut.
Blood flows anteriorly, from the sinus venosus to the bulbus cordis.
By 48 hours, the heart has folded upon itself, forming a single loop. This moves the sinus venosus and atrium to a position anterior and dorsal to the ventricle and the bulbus cordis. The ventricle is U-shaped and in the medial ventral position. Now, the blood flows posteriorly and then makes a sharp turn to flow anteriorly. In the 72-hour embryo, the atrium has begun to expand to the left in preparation of the division into the right and left atria.