Science, Tech, Math › Science Artery Structure, Function, and Disease Share Flipboard Email Print Science Biology Anatomy Basics Cell Biology Genetics Organisms Physiology Botany Ecology Chemistry Physics Geology Astronomy Weather & Climate By Regina Bailey Biology Expert B.A., Biology, Emory University A.S., Nursing, Chattahoochee Technical College Regina Bailey is a board-certified registered nurse, science writer and educator. Her work has been featured in "Kaplan AP Biology" and "The Internet for Cellular and Molecular Biologists." our editorial process Regina Bailey Updated May 09, 2019 01 of 03 What Is an Artery? Illustration of the arterial system in the human body, shown in a standing figure. Note the feathery network of blood vessels in the left and right lungs (next to the heart). Arteries are the blood vessels that carry oxygen-rich blood to the body's tissues. JOHN BAVOSI/Science Photo Library/Getty Images An artery is an elastic blood vessel that transports blood away from the heart. This is the opposite function of veins, which transport blood to the heart. Arteries are components of the cardiovascular system. This system circulates nutrients to and removes waste material from the cells of the body. There are two main types of arteries: pulmonary arteries and systemic arteries. Pulmonary arteries carry blood from the heart to the lungs where the blood picks up oxygen. The oxygen-rich blood is then returned to the heart via the pulmonary veins. Systemic arteries deliver blood to the rest of the body. The aorta is the main systemic artery and the largest artery of the body. It originates from the heart and branches out into smaller arteries which supply blood to the head region (brachiocephalic artery), the heart itself (coronary arteries), and the lower regions of the body. The smallest arteries are called arterioles and they play a vital role in microcirculation. Microcirculation deals with the circulation of blood from arterioles to capillaries to venules (the smallest veins). The liver, spleen and bone marrow contain vessel structures called sinusoids instead of capillaries. In these structures, blood flows from arterioles to sinusoids to venules. 02 of 03 Artery Structure Structure of an Artery. MedicalRF.com/Getty Images The artery wall consists of three layers: Tunica Adventitia (Externa)- the strong outer covering of arteries and veins. It is composed of connective tissue as well as collagen and elastic fibers. These fibers allow the arteries and veins to stretch to prevent over expansion due to the pressure that is exerted on the walls by blood flow.Tunica Media - the middle layer of the walls of arteries and veins. It is composed of smooth muscle and elastic fibers. This layer is thicker in arteries than in veins.Tunica Intima - the inner layer of arteries and veins. In arteries, this layer is composed of an elastic membrane lining and smooth endothelium (a special type of epithelial tissue) that is covered by elastic tissues. The artery wall expands and contracts due to pressure exerted by blood as it is pumped by the heart through the arteries. Arterial expansion and contraction or pulse coincides with the heart as it beats. The heartbeat is generated by cardiac conduction to force blood out of the heart and to the rest of the body. 03 of 03 Arterial Disease Atherosclerosis is a hardening of the arteries. This image shows an artery with cutaway section to reveal deposits of plague narrowing the passage for blood flow, illustrating the condition atherosclerosis. Science Picture Co/Getty Images Arterial disease is a vascular system disease that affect the arteries. This disease can impact various parts of body and includes arterial diseases such as coronary artery disease (heart), carotid artery disease (neck and brain), peripheral arterial disease (legs, arms, and head), and renal artery disease (kidneys). Arterial diseases result from atherosclerosis, or the build-up of plaque on arterial walls. These fatty deposits narrow or block artery channels resulting in decreased blood flow and increases the chances for blood clot formation. Decreased blood flow means that the body's tissues and organs do not receive enough oxygen, which may cause tissue death. Arterial disease may result in heart attack, amputation, stroke, or death. Risk factors for developing arterial disease include smoking, high blood pressure, high cholesterol levels, poor diet (high in fat), and inactivity. Suggestions for reducing these risk factors include eating a healthy diet, being active, and abstaining from smoking.