Atrium - GCSE Biology Definition

In GCSE Biology, the term atrium refers to one of the two upper chambers of the heart that receive blood before it moves to the lower chambers, called ventricles. The human heart has two atria: the right atrium receives deoxygenated blood from the body via the vena cava, while the left atrium receives oxygenated blood from the lungs through the pulmonary veins. The atria act as holding chambers, ensuring that the ventricles are filled efficiently. This supports effective pumping of blood throughout the body. Understanding the role of the atria helps students learn how blood circulates and how the heart maintains a constant flow of oxygen and nutrients to the body’s tissues.