Definition
Normal blood flow in children describes the normal path blood takes through the heart, lungs and body. Before describing normal blood flow, it is important to have a thorough understanding of normal heart anatomy. The heart has four chambers. The upper two chambers of the heart are called the right and left atria. The atria are the receiving chambers for blood returning from the body and the lungs. The wall dividing the two atria is called the atrial septum. The lower two chambers are the right and left ventricles. The ventricles are muscular chambers responsible for pumping blood to the body and lungs (see normal blood flow). The wall dividing the two ventricles is called the ventricular septum. There are four separate valves in the heart: the tricuspid valve, pulmonary valve, mitral valve, and aortic valve. The valves open to allow blood to flow forward and close to prevent any backflow. Finally, there are a number of veins and arteries attaching to the heart. The superior and inferior vena connect to the right atrium, while the pulmonary veins connect to the left atrium. The pulmonary artery connects the right ventricle to the lungs, while the aorta connects the left ventricle to the body.
The job of the heart is to pump blood to both the heart and the body. In the setting of normal blood flow, blue blood (blood without oxygen) returns from the upper body by way of the superior vena cava and from the lower body by way of the inferior vena cava. After collecting in the right atrium, it passes to the right ventricle. The right ventricle then pumps the blue blood out to the lungs through the pulmonary artery. In the lungs, the blood collects oxygen and turns a red color. Red blood (blood with oxygen) returns back from the lungs by way of the pulmonary veins. After collecting in the left atrium it passes into the left ventricle and from there is pumped to the body by way of the aorta.
Problems with normal blood flow
The term congenital heart defect refers to any abnormal variation in the normal heart anatomy present at birth. Congenital heart defects often affect the normal blood flow. A pediatric cardiologist is an expert in diagnosing and treating congenital heart defects, for example ventricular septal defect (VSD), atrial septal defect (ASD), patent ductus arteriosus (PDA), bicuspid aortic valve, aortic valve stenosis, aortic valve insufficiency, coarctation of the aorta, pulmonary valve stenosis, tetralogy of Fallot, transposition of the great arteries, and tricuspid atresia. Any or all of these heart problems may affect the course of normal blood flow in an otherwise healthy child.