Which chambers of the heart act as the primary pumping chambers, propelling blood to the lungs or to the rest of the body?

1. The heart has four chambers: a right and left atrium above, and a right and left ventricle below. 2. Each atrium acts as a receiving chamber that contracts to push blood into its corresponding ventricle. 3. The ventricles serve as the primary pumping chambers, propelling blood onward to the lungs or to the rest of the body. 4. Auricles are small ear-like extensions of the atria, and the venae cavae are veins returning blood to the heart, so neither is the primary pumping chamber. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 19 "The Cardiovascular System: The Heart", section 19.1, p. 825_