The image above shows a ventral view of a  frog heart. The amphibian heart contains three principal chambers, a thick-walled ventricle (1) and the thin-walled right atrium (2) and left atrium (3). The conus arteriosus (4) arises from the ventricle and divides to form the truncus arteriosus (5) on each side of the heart. Each truncus arteriosus divides into three major vessels, the pulmocutaneous arch (6) ,which goes to the lungs and skin, the systemic arch (7), which goes to the body, and the carotid arch (8), which go to the head region.