There are two types of blood vessels in the circulatory system of the body: arteries that carry oxygenated blood from the heart to various parts of the body and veins that carry blood towards the heart for purification.
|Oxygen Concentration||Arteries carry oxygenated blood (with the exception of the pulmonary artery and umbilical artery).||Veins carry deoxygenated blood (with the exception of pulmonary veins and umbilical vein).|
|Types||Pulmonary and systemic arteries.||Superficial veins, deep veins, pulmonary veins and systemic veins|
|Direction of Blood Flow||From the heart to various parts of the body.||From various parts of the body to the heart.|
|Anatomy||Thick, elastic muscle layer that can handle high pressure of the blood flowing through the arteries.||Thin, elastic muscle layer with semilunar valves that prevent the blood from flowing in the opposite direction.|
|Disease||artherogenesis- myocardial ischemia||deep vein thrombosis|
|Overview||Arteries are red blood vessels that carry blood away from the heart. resistance vessels||Veins are blue blood vessels that carry blood towards the heart. capacitance vessels|
|Thickest layer||Tunica media||Tunica adventitia|
|Location||Deeper in the body||Closer to the skin|
|Rigid walls||more rigid||collapsible|
|Valves||Aren't present (except for semi-lunar valves)||Are present, especially in limbs|
Differences in Function
The circulatory system is responsible for the delivery of oxygen and nutrients to cells. It also removes carbon dioxide and waste products, maintains of healthy pH levels, and supports the elements, proteins, and cells of the immune system. Two leading causes of death, myocardial infarction and stroke each may directly result from an arterial system that has been slowly and progressively compromised by years of deterioration.
An artery usually carries pure, filtered and clean blood away from the heart, to all the parts of the body with an exception of the pulmonary artery and the umbilical cord. As the arteries move away from the heart, they divide into smaller vessels. These thinner arteries are called arterioles.
Veins are needed to carry the deoxygenated blood back to the heart for purification.
Anatomy of Arteries vs Veins
Arteries that carry blood from the heart to other parts of the body are known as systemic arteries while those that carry deoxygenated blood to the lungs are known as pulmonary arteries. The inner layers of the arteries are generally made of thick muscles which is why the blood moves through it slowly. Pressure is built up and arteries are required to maintain their thickness to withstand the strain they endure. Muscular arteries vary in size from about 1 cm in diameter to about 0.5 mm.
Along with the arteries, Arterioles help in transporting the blood to various parts of the body. They are tiny branches of arteries that lead to capillaries and help maintain the pressure and blood flow in the body.
Connective tissues make up the outermost layer of a vein which is also known as - tunica adventitia or tunica externa. The middle layer is known as tunica media and is made up of smooth muscles. The interior is lined with endothelial cells called tunica intima. The vein also contains venous valves- one way flaps that prevent blood from flowing back and pooling in the lower extremities due to the effects of gravity. To ensure unrestricted flow of blood, a venule (blood vessel) allows deoxygenated blood to return from the capillary beds to the vein.
Types of arteries and veins
There are two types of arteries in the body: Pulmonary and systemic. The pulmonary artery carries deoxygenated blood from the heart, to the lungs, for purification while the systemic arteries form a network of arteries that carry oxygenated blood from the heart to other parts of the body. Arterioles and capillaries are further extensions of the (main) artery that help transport blood to tinier parts in the body.
Veins can be classified as pulmonary veins and systemic veins. The pulmonary veins are a set of veins that deliver oxygenated blood from the lungs to the heart and the Systemic veins drain the tissues of the body and deliver deoxygenated blood to the heart. Pulmonary and Systemic veins can either be superficial (can be seen or felt if touched on certain areas on the hands and legs) or embedded deep inside the body.
The arteries can get blocked and become incapable of supplying blood to the organs of the body. In such a case, the patient is said to suffer from peripheral vascular disease.
Atherosclerosis is another disease where the patient shows an accumulation of cholesterol on the walls of his arteries. This can be fatal in nature.
A patient can be affected by venous insufficiency, which is commonly known as varicose veins. Another disease of the vein, that commonly affects man is known as deep vein thrombosis. Here, a clot if formed in one of the 'deep' veins and can result in pulmonary embolism if not treated quickly.
Most arterial and vein diseases are diagnosed with an MRA scan.