Silent Essays - Angiology, Blood Pressure, Aorta, Artery, Blood

Silent Killer Uncontrolled high blood pressure, hypertension, is one of the leading causes of disability or death due to stroke, heart attack, heart failure and kidney failure. High blood pressure has been described as "the silent killer" because it often occurs without symptoms. Headaches, blurred vision, nosebleeds, or dizziness may occur, but these symptoms are not specific to high blood pressure. Everybody has, and needs blood pressure. Without it, blood cannot circulate through the body. And without circulating blood, vital organs cannot get the oxygen and food that they need to work. So it's important to know the role of blood pressure, and the organs and systems that help regulate it. The explanation of blood pressure begins with the cardiovascular system, the system responsible for circulating blood through the heart and blood vessels. When the heart beats, a surge of blood is released from the left ventricle, which is the heart's main pumping chamber, into an intricate web of blood vessels that spread throughout the body. The arteries are the blood vessels that carry nutrients and oxygenated blood from the heart to the body's tissues and organs. The largest artery, aorta, is connected to the left ventricle and serves as the main channel for blood leaving the heart. The aorta branches off into smaller arteries, which turn into even smaller arteries, called arterioles. (1) Within the body's tissues and organs are microscopic blood vessels called capillaries. The capillaries exchange nutrients and fresh oxygen from the arterioles for carbon dioxide and other waste products produced by our cells. This "used" blood is sent back to the heart through a system of blood vessels called veins. When it reaches the heart, blood from the veins is routed to the lungs, where it releases carbon dioxide and picks up a new supply of oxygen. This freshly oxygenated blood is sent back to the heart, ready to begin a new journey. Other waste products are removed as blood passes through the kidneys. (1) To keep this process working and all of the 11 pints of blood in our body moving, a certain amount of pressure is required. Blood pressure is the force that's exerted on the artery walls as blood passes through. This force helps keep blood in the arteries flowing smoothly. Several factors help control blood pressure and keep it from increasing too high or decreasing too low. They include three major organs; heart, arteries, and kidneys. When the heart releases blood into the aorta, a certain amount of force is created by the pumping action of the heart muscle. The harder the heart muscle has to work to release blood, the greater the force exerted on the arteries. To assist the surge of blood coming from the heart, the arteries are lined with smooth muscles that allow them to expand and contract as blood flows through. The more "elastic" the arteries are, the less resistant they are to the flow of blood and the less force exerted on their walls. When arteries lose their "elasticity" or become narrowed, resistance to blood flow increases and additional force is needed to push blood through the vessels. (1) The kidneys regulate the volume of water circulating in the body and the amount of sodium the body contains. More sodium in the body means that more water is retained in the circulation and may cause an increase in blood pressure. More sodium in the body also may increase the tendency for blood vessels to narrow. The central nervous system, hormones, and enzymes are other factors that also influence blood pressure. Within the walls of the heart and several blood vessels, are tiny structures called baroreceptors. The baroreceptors' job is to monitor the pressure of blood through the arteries and veins. If a change is noticed, the baroreceptors send signals to the brain; to slow down or speed up the heart rate, or to widen or narrow the arteries to keep the blood pressure within a normal range. (1) The brain reacts on the messages from the baroreceptors, by signaling the release of hormones and enzymes that affect the functioning of the heart, blood vessels, and kidneys. Epinephrine, adrenaline, is one of the most significant hormones to affect blood pressure. Epinephrine is released during high periods of stress or tension. The release of Epinephrine, causes the arteries to narrow and heart contractions become stronger and rapid, increasing the pressure on the arteries. Blood pressure is the measure of the force generated by the heart against the artery walls. This force is expressed as two numbers, such as 110 over