Chambers of the Heart

The heart has four chambers—the right atrium, right ventricle, left atrium, and left ventricle.

Externally, the coronary sulcus separates the atria and ventricles, while the anterior and posterior interventricular sulci divides the two ventricles.

Internally, the interatrial septum separates the atria, and the interventricular septum separates the ventricles.

The right atrium receives blood from the body, while the left atrium receives blood from the lungs.

Auricles, wrinkled pouch-like structures on the anterior surface of the atria, increase the atrial blood capacity.

An opening called the foramen ovale connects the atria in the fetal heart, permitting blood flow between them. After birth, this opening closes, and a depression called the fossa ovalis remains.

The right ventricle pumps blood to the lungs, while the left ventricle pumps blood to the rest of the body with higher pressure.

The internal walls of the ventricles have irregular muscular ridges called the trabeculae carneae.

The papillary muscles and their associated chordae tendineae in the ventricular walls regulate valve function.