Protein signalling in heart development Protein signalling in heart development The heart is the first functional organ in a vertebrate embryo. There are 5 stages to heart development. Specification of cardiac precursor cells: The lateral plate mesoderm delaminates to form two layers: the dorsal somatic (parietal) mesoderm and the ventral splanchnic (visceral) mesoderm. The heart precursor cells come from the two regions of the splanchnic mesoderm called the cardiogenic mesoderm. These cells can differentiate into endocardium which lines the heart chamber and valves and the myocardium which forms the musculature of the ventricles and the atria. The heart cells are specified in anterior mesoderm by
Crisscross heart and right ventricle are working together to supply blood to the pulmonary artery, similarly to how the left atrium and the left ventricle work simultaneously to supply blood to the aorta. During the process of the heart contracting and releasing the right atrium and left atrium contract at the same time, while the left ventricle and right ventricle relax. In opposition, when the left atrium and right atrium are relaxed the left ventricle and right ventricle contract pushing blood to either the aorta or pulmonary artery. In an anatomically correct heart the atria are smaller than the ventricles. The ventricles