Yes, atria and atrium refer to the same thing. The term “atrium” is the singular form, while “atria” is the plural form. In anatomy, the atrium refers to the upper chambers of the heart that receive blood. Humans have two atria: the left atrium and the right atrium.
The right atrium receives deoxygenated blood from the body and pumps it to the right ventricle. The left atrium receives oxygenated blood from the lungs and pumps it to the left ventricle. Both atria play a crucial role in the circulation of blood throughout the body.