The heart muscle is made up of cardiac fibers and is the pump that sends blood to the body cells. It is composed of two upper chambers, or atria, and two lower chambers, ventricles. Blood comes from the body to the atria and is pumped to the body by the ventricles. The atria are primer pumps, and the ventricles are power pumps. The right atrium receives blood from all parts of the body except the lungs. The left atrium receives blood from the lungs. The right ventricle pumps blood to the lungs and the left ventricle pumps blood to the rest of the body.
Oxygen-depleted blood comes back from the lungs through the vena cava to the right atrium. It then passes through the tricuspid or right atrioventricular (AV) valve into the right ventricle. When the right ventricle contracts, blood is forced from the heart into the pulmonary artery through the pulmonary semilunar valve back to the lungs. Oxygenated blood returns to the left atrium, goes through the mitral or left AV valve to the left ventricle where it is pumped through the largest body artery, the aorta, to all parts of the body besides the lungs. The left ventricle walls are thicker and more powerful than those of the other three heart chambers.
For the past several blog posts, I have not created exercise programs. Look to past posts or search by muscle group, and you will find them!
Disclaimer: None of the above information can be taken as a substitute for advice from a medical professional, such as a physician.
My third book, Pocket Guide to Fitness, is available on www.louizapatsis.com, http://www.authorhouse.com, www.bn.com and http://www.amazon.com. If you look up my name on those Web sites, you will find my other books The Boy in a Wheelchair and Life, Work and Play: Poems and Short Stories.