Introduction:
The Heart is made up of a powerful muscle called Myocardium. The Myocardium is composed of cardiac muscle fibers that contracts and causes a wringing type of action. The size of you heart is a little larger than the size of your fist. The location of the heart is about left-center of your chest. The heart are two separate pumps that continuously sends blood throughout the body carrying nutrients, oxygen, and helping remove harmful wastes. The right side of the heart receives blood low in oxygen. The left side of the heart receives blood that has been oxygenated by the lungs. The blood is then pumped out into the Aorta and to all parts of the body. The Heart Diagram above and the information that follows will give a better understanding of the heart structure and how the blood circulates through the heart.
Right Atrium:
The Right Atrium is larger than the Left Atrium but has thinner walls. The Right Atrium has two major veins that returns blood to the heart from all parts of the body. Two major veins returning the blood to the heart are the Superior Vena Cava and the Inferior Vena Cava. These two veins are sometimes called the "Great Veins". The Superior Vena Cava returns the deoxygenated blood from the upper part of the body and the Inferior Vena Cava returns the deoxygenated blood from the lower part of the body. The Right Atrium also receives blood back from the heart muscle itself. After the blood is collected in the Right Atrium it is pumped into the Right Ventricle through the Tricuspid Valve (three leaf valve).
Left Atrium:
The Left Atrium receives blood from four Pulmonary Veins. The blood received from the lungs has been oxygenated. The oxygenated blood that is collected in Left Atrium is then pumped into the Left Ventricle through the Bicuspid Valve.
Right Ventricle:
The Right Ventricle receives blood from the Right Atrium. When the Heart contract the blood is forced out through the Pulmonary Semilunar Valve into the Pulmonary Artery. The Pulmonary Semilunar Valve is a three flap valve that stops the backflow of blood. The walls of the Right Ventricle are a little thicker than the Right Atrium.
Left Ventricle:
The chamber of the Left Ventricle has walls that are three times the thickness of the Right Ventricle. This is important because the oxygenated blood that it receives from the Left Atrium has to be pump throughout the body. The Bicuspid Valve closes and the blood is collected in the Left Ventricle. The closing of the Bicuspid Valve stops the backflow of blood. When the Heart muscle contracts the blood is forced through the Aortic Semilunar Valve which has the same features as the Pulmonary Valve. The blood then passes through the Aortic Semilunar Valve into the Aorta.
Aorta:
The Aorta is the largest blood vessel in the body. The inner diameter of the Aorta is about 1 inch. The Aorta carries oxygenated blood to every other part of the body. The Aorta receives it's blood from the Left Ventricle.
Septum:
The Septum is a partition that separates the right and left sides of the Heart. There are two separate regions of the Septum. They are the Interatrial Septum that separates the Atriums and the Interventrial Septurm that separates the Ventricles. The Interatrial Septum is only present in the fetal period and is open during this period. The Interatrial Septum closes at the time of birth. The Interventrial Septum is suppose to be closed all the time but sometimes an opening is present at birth. This would be considered a Congenital heart disease.
Superior Vena Cava:
The importance of the Superior Vena Cava is to return blood back to the Right Atrium from the upper part of the body. It is one of the largest veins in the body.
Inferior Vena Cava:
The Inferior Vena Cava is important for carrying the blood back to the Right Atrium from the lower part of the body.
Pulmonary Arteries:
The Pulmonary Arteries carry the blood from the Right Ventricle to both of the lungs. There the blood is oxygenated and sent to the Left Atrium in the heart.
Pulmonary Veins:
The Pulmonary Veins carry the oxygenated blood back to the Left Atrium in the heart.
