Arteries and veins are both vessels in the circulatory system that carry blood through the body. The difference between the two is that arteries carry blood away from the heart and veins carry blood back to the heart.
Function of Arteries
Arteries, which are larger than veins, carry blood away from the heart to provide oxygen and nutrients to the body. Since arterial blood is enriched with oxygen, it is bright red.
Function of Veins
After blood is depleted of oxygen and nutrients, it is carried back to the heart through veins. Blood in veins is usually dark red because it lacks oxygen. The only exception to this are the pulmonary veins.
The four veins that carry blood from the lungs to the heart are called pulmonary veins. Unlike other veins, the blood in pulmonary veins is full of oxygen. The blood is pumped in to the the left atrium of the heart and then circulated throughout the body by arteries.
Deep Vein Thrombosis
A serious venous condition occurs when a blood clot forms in a deep vein (deep vein thrombosis), most commonly in the leg. One of the dangers of a deep vein clot is that it can break loose from the vein and travel to the lungs causing a pulmonary embolism, which can be fatal.
Peripheral artery disease (PAD) and coronary artery disease are two common and extremely serious arterial conditions. PAD occurs when the arteries in the arms or legs narrow and the limbs do not get enough blood. PAD occurs most commonly in the legs. PAD is widespread and experts estimate that it affect 8 million Americans. Untreated, PAD can lead to heart attack or stroke, according to the American Heart Association. When the main arteries of the heart become narrowed or damaged from a build up fatty plaque deposits it is a condition called coronary artery disease (CAD). If the arteries become completely blocked, blood flow is stopped and it results in a heart attack. More than 650,000 people in the U.S. die each year from CAD, according to the Centers for Disease Control and Prevention.