PATHOLOGY

Detailed explanation-1: -The heart has four chambers: two atria and two ventricles. The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle. The right ventricle pumps the oxygen-poor blood to the lungs. The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle.

Detailed explanation-2: -There are two pouches which comprise the right atrium, the main cavity, and also a small chamber projecting to the left (lying on the anterior surface, and partly covering the root of the aorta) like an ear. This is the auricle.