what does the atria do in the heart
Atrium (heart) The atrium is the upper chamber in which blood enters the heart. There are two atria in the human heart, which receive blood - the left atrium from the lungs, and the right atrium from the venous circulation. The atria receive blood, and when the heart muscle contracts, pump blood to the ventricles. All animals with a closed circulatory system include at least one atrium / auricle (humans have two atria).
Heart The heart is a muscular organ in most animals, which pumps blood through the blood vessels of the circulatory system.[1] Blood provides the body with oxygen and nutrients, as well as assists in the removal of metabolic wastes.[2] In humans, the heart is located between the lungs, in the middle compartment of the chest.[3]