Take Heart!

The human heart has long been romanticized as being the center of our body's spirit.  It is an organ that works tirelessly, pumping blood to all parts of the body from the day it is formed until the day that it dies.  It never takes a vacation; never takes a nap; never really rests.  Based on an average of 80 beats per minute, your heart beats 115,000 times each day!  That is an astonishing 42,000,000 times per year.  It is estimated that approximately 1,000,000 barrels of blood is pumped through the heart in an average lifetime!  That's a lot of work for a small organ!  Perhaps it is this loyalty that has given it its mystic, almost magical reputation.  To further investigate the beating action of the heart, check out these sites:

Blood Flow Through The Heart
The human heart is actually two pumps sharing a common wall (called the septum).  Blood entering the heart on the right side is deoxygenated (oxygen poor) and is returning from tissues and organs throughout the body.  This deoxygenated blood enters the right atrium through the superior and inferior vena cava.  A small amount of blood also enters the right atrium through the coronary sinus.  Blood entering through the coronary sinus is deoxygenated blood returning from the heart wall itself.  From the right atrium, blood travels through the bicuspid valve into the lower chamber on the right side, the right ventricle.  This muscular chamber then pumps blood through the pulmonary semilunar valve into the pulmonary artery trunk and on into the right and left pulmonary arteries.  These vessels deliver the deoxygenated blood to the lungs.  On the diagram below, this pulmonary circuit is highlighted in blue. (If you cannot view this diagram, try opening this page in Internet Explorer.)
 
 
 

The red portions of the diagram represent the systemic circuit of circulation.  Oxygenated blood enters the left side of the heart through the pulmonary veins.  These veins travel to the heart directly from the lungs.  Blood fills the left atrium, travels through the bicuspid (or mitral ) valve and fills the left ventricle.  The powerful left ventricle contracts, sending blood through the aorta and all of its branches that ultimately reach the body's tissues and organs.  Please note that there is no mixing of blood between the left and right sides of the heart!

Want to test your own knowledge?   Heart Anatomy has photographs of heart models with a point and click identification system.  It even has a quiz to test your own abilities!  This site is excellent for those of you studying anatomy lab!

Finally, I am sure that each of us has known someone suffering from some form of heart disease.  For information on many common cardiac conditions and diseases just click the link.