The septum, not a specialized name, presumably refers to the intervals of the heart, made up of heart muscle and connective tissue. The heart has an interatrial septum between the right and left atria and a ventricular septum between the right and left ventricles, dividing the heart into a left heart and a right heart, which carry out the body and pulmonary circulations, respectively. Blood from the left atrium returns to the left ventricle, where the blood is arterial, and the left ventricle ejects blood into the aorta to supply nutrients to the organs and tissues. Blood from the right atrium returns to the right ventricle, where the blood is venous, and the right ventricle ejects blood to the pulmonary artery, where it receives nutrients by means of the ventilatory function of the lung tissue. The interatrial septum is located between the right and left atria, and the ventricular septum is located between the right and left ventricles. The integrity of the septum ensures that the arterial and venous blood do not mix, and that the physical and pulmonary circulations do not interfere with each other, thus ensuring normal circulation and blood flow. If there is a defect, such as an atrial septal defect or a ventricular septal defect, it is a congenital heart disease and requires regular cardiology or cardiac surgery and prompt surgical treatment.