What chambers of the heart receive blood from the body, ventricles or atria? what chambers of the heart pump blood out of the heart, ventricles or atria? which heart chamber has the thickest muscle wall? 20.why is it necessary for the chamber in the above question to have a thicker muscle wall? which blood vessel brings oxygen poor blood to the heart from the rest of the body? which blood vessel takes blood from the heart and sends it to the lungs? which blood vessel takes oxygen-rich blood from the lungs and brings it back to the heart? which blood vessel sends oxygen-rich blood from the heart to the rest of the body? how do the valves control the flow of blood through the heart? answer the conclusion questions.