The heart chamber is composed of four parts: the atria (5 letters), the AURICLE (7 letters), the ATRIUM (6 letters), and the ventricle (9 letters). The atria are the two upper chambers of the heart, which receive blood from the veins. The auricles are small, ear-shaped appendages that project from the atria. The ATRIUM is the larger of the two lower chambers of the heart, which pumps blood to the lungs. The ventricles are the two lower chambers of the heart, which pump blood to the rest of the body. Together, these four parts make up the heart chamber, which is responsible for pumping blood throughout the body.