Cardiovascular Cure How to Strengthen Your Self-Defense Against Heart Attack and Stroke

Chapter 1 Your Blood Vessels and NO (and Why You Need to Know about Them) This is a story about the health of your blood vessels. If you are like most people, you have probably given some thought to the health of your heart, but not the 100,000 miles of blood vessels that run throughout your body. Wherever blood flows in your body, it flows through blood vessels. Blood vessels have been given short shrift mainly because people think that they are nothing more than passive pipes. But we now know that they are much more important than anyone ever realized. Your blood vessels are dynamic, living tissue just like any other organ in your body. And just like every other organ, they perform a vital function: in this case, controlling blood flow from one moment to the next. Every 60 seconds, your vessels are responsible for distributing five quarts of life-sustaining blood to your body. Just think, five quarts every minute, 1,800 gallons every day, a virtual river of life. Composed of living cells, blood is alive. And like all living things, blood has its own complex functions. It carries the oxygen and nutrients your tissues need to survive. It removes the waste products of cellular metabolism, distributing these to the liver or kidney where the waste products can be excreted. Blood carries hormones from the brain and other glands to distant parts of the body where these hormones are needed for the growth and function of each organ. When you cut yourself, blood has the ability to clot and stop the bleeding. And when you lose blood, your body has the ability to make new blood, replacing what's been lost. Blood carries white blood cells, your body's major defense against infection. White blood cells course through all of the blood vessels, constantly patrolling for foreign invaders. If you think about it, blood is the unifying force within the body, both a link between distant parts and an intricate system of transportation that provides fuel, disposes of waste, and carries disease-fighting cells. And all of this happens within the blood vessels. As the conduit, blood vessels play a role in the ability of the blood to do its job. Blood vessels can control their own diameter and control the flow of blood from one moment to the next. They can open up to increase the flow of blood to where it is needed (such as to the muscles during exercise or to the pelvis during sexual intercourse). Blood vessels can also reduce the flow of blood to an area of the body. The blood vessels to the skin constrict or shut down completely when blood must be diverted (which is why a person may become pale with fear when blood is diverted from the skin to the muscles, heart, and brain where it is needed for fight or flight). Blood vessels can do this because their walls are made of muscle, similar to that of the heart muscle. This muscle responds to nervous impulses from the brain, to changes in pressure within the vessel, and to substances made by the endothelium, the inner lining of the blood vessel. Blood vessels are always active and constantly in motion as they respond to the rhythms of the body: the heart, the flow of blood, signals from the brain, and signals from tissues of the body that need more blood. Like so many other parts of the body, blood vessels do their job without our conscious knowledge. The small and large blood vessels perform different roles. The smaller vessels contract to restrict blood flow and dilate to increase it. They direct the flow of blood where it is needed. On the other hand, the larger vessels do not contract or dilate very much on their own, but instead respond to the beat of the heart. They expand with each beat, much as the inner tube of a tire expands when it is filled with air. When the heart relaxes between beats, the walls of the great vessels (the aorta, which carries blood from the heart to the rest of the body, and the pulmonary artery, which carries bCooke, John P. is the author of 'Cardiovascular Cure How to Strengthen Your Self-Defense Against Heart Attack and Stroke', published 2002 under ISBN 9780767908818 and ISBN 0767908813.