About 7 percent of you, by weight, is blood. For the average adult, that’s five to six quarts, or 4 to 6 liters, or for the barfly, 10 pints of blood in your body at all times (think about that next time you drink a few pints). That’s a lot of blood, and it’s not as though it’s just sitting there, it’s constantly pumping and flowing through your circulatory system, performing the critical task of delivering oxygen and nutrients to the cells of the body.
It’s a herculean task the circulatory system performs, and if you don’t think so, consider for a minute that your heart has been beating nonstop, and will continue to do so, as long as you’re alive. That’s a workhorse. All that work would be fruitless were it not for the intricate system of veins and arteries providing transport for the blood. One of the key components of that system is the aorta, the hose-like blood vessel that transports blood from the heart to the body. This article will examine one component of the aorta, the thoracic aorta, its role in the circulatory system, and some possible complications that can occur related to it.
The Circulatory System
The human circulatory system is a closed system, meaning all of the blood stays within the network of vessels and the heart. It’s composed of the heart and the blood vessels (although sometimes the lymphatic system is considered part of the circulatory system) and is chiefly responsible for delivering blood to the body’s cells to supply oxygen and nutrients, and then returning deoxygenated blood and waste back to the lungs to be recycled and sent back out.
There are two main “loops” in the circulatory system, both of which travel through arteries on the way out of the heart, and through veins on the way back to the heart. One loop is the pulmonary circulation, which carries deoxygenated blood to the lungs, where the lungs replenish it with oxygen and send it back to the heart for deployment. The second loop, the systemic circulation, carries the oxygen-rich blood out to the body and then back to the heart.
The arteries of the body start with the aorta, then split into smaller and smaller branches that reach out to the body’s organs. At the smallest level, the capillaries are microscopic blood vessels the width of a single cell. The deoxygenated blood then travels through the veins, back to the heart where the lungs will replenish it.
The aorta is the beginning of the half of the systemic circulation that carries the blood out from the heart to the body, through the arteries. It is the largest artery, connecting directly to the heart and out to the rest of the smaller arteries, sort of like a big spigot or a water main. It’s about a half inch to an inch in diameter. Arteries are tubes made up of a wall with several layers. The intima is the innermost layer, which has a smooth surface. The media is muscle and fiber that can expand and contract as the heart pumps blood. And the adventitia is the outer layer, which is like a casing that provides structure.
The aorta begins at the top left ventricle of the heart, the muscular pump that sends blood out, through an aortic valve that opens and closes with the pumping. The aorta ascends up to the aortic arch which forms a hook resembling a candy cane, with the stem of the cane being the thoracic aorta and then the abdominal aorta further down. All of the arteries branch off from the aorta, feeding the cells in the body as the aorta rises and then descends. First the coronary arteries split off and deliver blood directly to heart itself. Then in the aortic arch, three branches deliver blood to the arms and head. Beyond the last branch of arteries coming off of the aortic arch is the beginning of the descending thoracic aorta.
The thoracic aorta is the portion of the aorta that starts where the aortic arch curves and starts to descend, and continues until it the abdominal aorta. The first artery of the abdominal aorta is the celiac artery, which signals the end of the thoracic artery. The abdominal aorta then ends by splitting into two arteries, the common iliac arteries, which continue down the legs.
The thoracic aorta, like the other sections of the aorta, is somewhat of an arbitrary distinction. Which is to say, there’s really nothing that separates it from the rest of the aorta, other than a useful way to distinguish the different sections. It begins on the left side of the vertebrae, then winds around the vertebrae and ends in front. The branches that come off of the thoracic aorta supply blood to the esophagus, the lungs, the chest area, the ribs and mammary glands. The branches of arteries extending from the thoracic aorta are all relatively small, with the bulk of the body’s major organs supplied further down by the abdominal aorta.
The thoracic aorta is the portion of the aorta that is mostly toward the back of the body, so symptoms of problems with the thoracic aorta often will manifest as back pain, with sufferers confusing it with muscle or spinal pain.
Because the aorta plays such an integral role in the transport of blood to the rest of the body, health problems in this area can be very serious. Here are two potential complications:
Anueurysm: The thoracic aorta aneurysm, or TAA, is an abnormal widening of the aorta due to a bulging in the wall of the artery. An aneurysm can happen in many places, but the thoracic aorta aneurysm occurs in the chest. An aneurysm will gradually grow in size and can result in a rupture, which can cause life-threatening bleeding. They can be treated by reducing contributing factors, medication or surgery.
Aortic atherosclerosis: This Is when cholesterol plaques builds up in the walls of the aorta and builds up pressure in the artery. High blood pressure and cholesterol contribute to this problem, which can result in a stroke.
If you have any symptoms such as a pain in the chest, neck and/or back, swelling of the head, neck and arms or wheezing, coughing and shortness of breath, consult with a physician right away.