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Vein Information – How Do Veins Work?

The blood in our bodies flows through a system of vessels that are called arteries and veins. The arteries carry blood that is rich in oxygen from the heart to all of the areas in our bodies. The veins then transport the oxygen-depleted blood that is returning to the heart.

Anatomy of the veins graphic

Descriptions About Veins & Arteries

  • Arteries are the largest veins in our bodies. They carry blood from the heart to the other regions in our bodies. The main artery is called the aorta.
    • Do arteries carry blood away from the heart? – Yes. Arteries are responsible for carrying oxygenated blood away from the heart. It is the veins that are responsible for carrying de-oxygenated blood back to the heart.
    • There are smaller arteries too and these are called arterioles. These arterioles diverge into something called capillary beds. These capillary beds each have between 10 and 100 capillaries that then branch off into the tissues and cells of the body.
  • Capillaries carry the nutrients through the bloodstream to exchange them with tissue and cells. They also exchange oxygen and waste with the tissues on the cellular level. Capillaries have a single layer of cells called the tunica intima or the endothelial tunica. This is where the exchange and diffusion of materials occurs.
  • Veins are a type of blood vessel that brings the blood back to the heart. They drain the blood from our limbs and organs. Arteries are the opposite of veins. Human veins, if extracted and laid out in a line, could reach over 100,000 miles. The largest ones are the inferior vena cava and the superior vena cava. They transport large quantities of blood to the heart from many different parts of the body.
  • Arteries and veins have two more tunics surrounding the endothelium. One of these, the middle tunica, is made from smooth muscle that regulates the flow of blood. The other, the outer tunica, external is made from connective tissues that support the blood vessels.

Leg Vein Information

Blood gets squeezed from the veins in our legs when the muscles in our calves contract. When these muscles relax again, the valves that are in the veins will close temporarily. This keeps the blood from flowing away from the heart going the wrong way.

The human body has a complicated, beautiful, and functional circulatory system. It ensures the entire body has the blood it needs at all times.

Types of veins found in the legs

There are only 3 kinds of veins in our legs. They are deep veins, perforating veins, and superficial veins. The perforating veins are what connect the superficial veins to the deep veins. When we are in a standing position, the superficial veins are vertical just below the surface of our skin and most of the time can be seen with ease. These veins are only responsible for the transportation of around 10% of the blood in our legs. The blood in those veins goes right to the perforating veins. These veins run perpendicular to the superficial ones. The deep veins can be found deep in the leg muscles and are parallel to the superficial ones. The deep veins carry 90% of the blood in the legs.

How Venous Diseases Affect the Veins

When we suffer from a venous disease, the internal walls of the veins in the legs become deteriorated. The small valves can become incompetent and defective. When this happens to valves, either in the superficial or the deep vein system, the blood can flow back to the foot. This is known as reflux.

When valves in the superficial veins are incompetent, more stress is put on the deep veins. They are responsible for carrying more blood bakc to the heart than ususal. Not an ideal situation long term.

In order to compensate for this, these veins will expand which can lead to the valves not functioning properly. This can lead to the deep vusualstem also becoming incompetent.

When this happens, the peripheral veins will retain the blood even while we are walking. This means that the pressure in those veins will not lower. This is known as CVI or chronic venous insufficiency. This can lead to ulcerations, skin changes, and edema. Varicose veins are the most common vein disease, get more varicose vein information here.

Want to learn more?

If you want more info on varicose veins or vein information specific to other venous diseases (there are several), view our services pages or contact the Vein Institute of Utah today.