Your heart is located under the ribcage in the center of your chest between your right and left lungs. Its muscular walls beat, or contract, pumping blood continuously to all parts of your body.
The size of your heart can vary depending on your age, size, and the condition of your heart. A normal, healthy, adult heart most often is the size of an average clenched adult fist. Some diseases of the heart can cause it to become larger.
Diagrams of the heart and blood flow Left Side of the Heart
The blood coming from the lungs to the heart collects in the Left Atrium, filling it up. This initiates a contraction of the walls of the Left Atrium forcing the Mitral Valve to open as the blood gushes into the Left Ventricle.
The Left Ventricle fills with blood which forces the Mitral Valve to close and initiates the muscle of the Left Ventricle to contract, open the Aortic Valve, and squeeze the blood through the Aortic Valve and on to the body.
The blood coming out of the Left Ventricle to the Aorta is under high pressure. This pressure is enough to rush it t
o the different parts of the body at high velocity and give its oxygen and nutrients to the body tissues. The blood comes back from the body to the right side of the heart.
Diagrams of the heart and blood flow Right Side of the Heart
The blood coming from the body to the heart collects in the Right Atrium, filling it up. This initiates a contraction of
the walls of the Right Atrium forcing the Tricuspid Valve to open as the blood gushes to the Right Ventricle.
The Right Ventricle fills with blood which forces the Tricuspid Valve to close and initiates the muscle of the Right Ventricle to contract, open the Pulmonic Valve and squeeze the blood through the Pulmonic Valve and on to the lungs.
This blood will replenish itself with more oxygen and get rid of the carbon dioxide and return to the left side of the heart to begin another cycle.
Diagrams of the heart and blood flow
All blood enters the right side of the heart through two veins: The superior vena cava (SVC) and the inferior vena cava (IVC) (see figure 3).
The SVC collects blood from the upper half of the body. The IVC collects blood from the lower half of the body. Blood leaves the SVC and the IVC and enters the right atrium (RA) (3).
When the RA contracts, the blood goes through the tricuspid valve (4) and into the right ventricle (RV) (5). When the RV contracts, blood is pumped through the pulmonary valve (6), into the pulmonary artery (PA) (7) and into the lungs where it picks up oxygen.
Why does it happen this way? Because blood returning from the body is relatively poor in oxygen. It needs to be full of oxygen before being returned to the body. So the right side of the heart pumps blood to the lungs first to pick up oxygen before going to the left side of the heart where it is returned to the body full of oxygen.
Blood now returns to the heart from the lungs by way of the pulmonary veins (8) and goes into the left atrium (LA) (9). When the LA contracts, blood travels through the mitral valve (10) and into the left ventricle (LV) (11). The LV is a very important chamber that pumps blood through the aortic valve (12) and into the aorta (13). The aorta is the main artery of the body. It receives all the blood that the heart has pumped out and distributes it to the rest of the body. The LV has a thicker muscle than any other heart chamber because it must pump blood to the rest of the body against much higher pressure in the general circulation (blood pressure).