Anatomy, Arteries

Excerpt

Arteries constitute a major component of the circulatory system, with veins and the heart as the other main components. Arteries are tubelike structures that transport fluid (ie, blood in the circulatory system and lymph in the lymphatic system) to and from every organ in the body. Arteries primarily transport oxygen, nutrients, and hormones throughout the body. Arteries deliver fresh oxygen to the body after it is loaded onto the Fe²⁺ at the center of hemoglobin. Oxygen binds to hemoglobin and is transported by the arteries to tissues that lack oxygen. Through a shift in oxygen affinity, it is then unloaded into specific tissues via capillaries with high surface area. Far from being static structures, arteries adapt in response to signals from the central nervous system and to external stimuli, including pressure, temperature, and chemical agents. Vascular nerves innervate arteries, enabling them to respond to stimuli. As catecholamines are released into the bloodstream, nerves signal to arteries to constrict or dilate, thereby altering blood pressure.

Arteries are composed of smooth muscle, which allows constriction and dilation via the parasympathetic nervous system. Arteries differ from veins in that they typically carry oxygenated blood away from the heart and into the rest of the body. However, this is not always the case, as the pulmonary artery transports unoxygenated blood from the heart to the lungs for gas exchange in the alveoli. Additionally, arteries play an important role in maintaining adequate blood flow to the uterus during pregnancy, thereby supporting fetal growth. Arteries play a crucial role in maintaining homeostasis in the body. Additionally, arteries become clogged by a thickening of the plaque, a process known as atherosclerosis.

As individuals age, health issues often manifest as arterial stiffening or thickening. This issue may develop due to a variety of issues, ranging from advanced age, poor diet, sedentary lifestyle, and/or genetic factors such as hypercholesterolemia. As problems arise in the structure of the arteries, it begins leading to more strain on the heart, which develops congestive heart failure, and which is often fatal. More commonly, arteries continue to develop plaque, which eventually leads to an obstruction of blood flow to vital organs, including the heart. Coronary arteries are crucial for supplying the heart with blood; however, like other arteries, they are prone to atherosclerosis in untreated high-risk individuals. Depending on the location of the obstruction in the coronary arteries, blood flow to a particular segment or, in some cases, to the entire heart may be arrested. Ischemia of the cardiac muscle may be evidenced by ST elevations on EKG monitoring strips and by a rise in troponin, a significant marker of cardiac injury. If the ischemia persists, the individual may experience myocardial infarction, otherwise known as a heart attack. The arteries are vital to maintaining a healthy cardiovascular system and, consequently, a healthy lifestyle.