A Labeled Diagram of the Human Heart

The human heart resembles the shape of an upside down pear, weighing between 7-15 ounces, and is little larger than the size of the fist. It is located between the lungs, that is in the middle of the chest, behind and slightly to the left of the sternum or breast bone. The heart, one of the most significant organs in the human body, is nothing but a muscular pump, which pumps blood throughout the body. The heart beats approximately 72 times per minute, and pumps blood, carrying vital nutrients required by the body. The pumped blood also removes waste products from the body. Observing a diagram of the heart, as the one here, will help comprehend the different parts of the human heart.

Structure of the Human Heart
The human heart is covered by a double layered membrane called the pericardium, of which the outer layer surrounds the roots of the major blood vessels of the heart. It is attached to the spinal cord, diaphragm and other parts of the body via ligaments. The inner pericardium layer is double layered and attached to the heart muscle. It is separated from the outer layers by a pericardial fluid.

Atria and Ventricles:
In the labeled diagram of the human heart, one can observe that the heart comprises four chambers. The two upper chambers are called the left and the right atria, and the two lower chambers are known as the left and the right ventricles. The two atria and ventricles are separated from each other by a muscle wall called 'Septum'. The septum separating the ventricles from each other is clearly visible in the labeled diagram of the heart. The right atrium is larger than the left one, and has thinner walls as compared to the left atrium. This can also be observed in the diagram of the heart. The left ventricle on the other hand is the strongest and largest chamber in the heart. Its walls are only half-inch thick, however, they possess the strength to push the blood.

Valves:
The heart features four types of valves which regulate the flow of blood through the heart. These valves have been clearly shown in the labeled diagram of the heart. These valves permit blood flow only in one direction, and prevent back flow of blood. The four types of valves are:

Tricuspid Valve: As observed in the labeled diagram of the human heart, this valve separates the right atrium from the right ventricle, and regulates the blood flow between them. Tricuspid valves allow blood to flow from the right atrium into the right ventricle, and prevent back flow of the same.

Pulmonary Valve: In the human heart anatomy diagram, one can observe that this valve separates the right ventricle from the left pulmonary artery. These valves prevent the control the flow of blood from the right ventricle into the left pulmonary artery.

Mitral Valve: Bicuspid valve or Mitral valve as observed in human heart diagram separates the left ventricle from the left atrium.

Aortic Valve: As seen in the labeled diagram of the heart, this valve separates the left ventricle from the aorta, and controls the blood flow from the ventricle into the rest of the body.

Blood Vessels:
Arteries: Arteries are smooth on the inside and tough on the outside. Their muscular wall helps the heart to pump blood. When the heart beats, the arteries expand and get filled with blood. When the heart relaxes, contraction of the arteries takes place, which exert enough force to push the blood along the blood vessels. It is this rhythmic movement between the heart and arteries which result in an efficient circulation system. Arteries transport oxygen-rich blood to the capillaries, where actual exchange of carbon dioxide and oxygen takes place. The arteries of the heart are:

Pulmonary Artery: Usually arteries are characterized with the transport of oxygenated blood, however, the pulmonary artery is an exception. It carries deoxygenated blood from the right side of the heart to the lungs for purification. The pulmonary artery divides into the right and left branch, which take the blood to the right and left lung respectively.

Aorta: This is the main artery of the heart, which carries oxygenated blood from the left side of the heart to the rest of the body. This main artery branches into several smaller arteries, which then supply fresh oxygenated blood to the body.

Coronary Arteries: The coronary arteries are attached to the heart and supply oxygenated blood to the heart muscles.

Veins: Veins are like arteries, however, are not as strong as arteries as they do not have to transport blood at high pressure. After the exchange of carbon dioxide and oxygen takes place between the arteries and capillaries, the blood containing waste products is received by the veins. The major veins of the heart are:

Pulmonary Vein: The veins are generally characterized as blood vessels, which carry deoxygenated blood to the lungs, however, the pulmonary vein is an exception. It carries oxygenated blood from the lungs to the left side of the heart. The pulmonary vein has four branches: two right pulmonary veins and two left pulmonary veins. All four branches pour oxygenated blood into the left atrium of the heart.

Vena Cavae: These are two large veins carrying de-oxygenated blood from the body to the heart. The superior vena cava brings deoxygenated blood from the parts of the body located above the heart, such as chest, arms, neck and head regions into the right atrium. The inferior vena cava on the other hand collects blood from the parts of the body located below the heart into the right atrium. In the labeled diagram of the human heart, both the superior as well as the inferior vena cava is clearly shown.

The heart's working system is really remarkable. This hollow muscular organ pumps blood via a well-organized network of blood vessels. It comprises valves which allow the blood to flow only in one direction. The blood pumped by the heart not only provides nutrients to the body cells, but also removes the waste materials from different parts of the body. The above labeled diagram can be modified as per your requirements for kids use. The heart diagram for kids can be printed and colored to make it easier to understand.