Anatomy of Your Veins
The blood veins in your body are part of a huge network that make up the cardiovascular system, and are made to transport blood back to your heart. Nearly all the veins carry deoxygenated blood from various parts of the body to the heart, via the inferior and superior vena cava, with the exception of the pulmonary veins that carry oxygenated blood from your lungs through to the left atrium of the heart.
Unlike the arterial system that relies on the heart to pump blood at high pressure to the whole body, the venous system is a low pressure system that depends on muscle contractions and valves to return blood to the heart and prevent backflow, respectively. Problems affecting the veins usually arise from blood clots or vein defect, such as expanded vein walls and weak valves, causing blood to flow back or pool and result in varicose veins or another venous disorder.
Types of Veins
There are four broad categories of veins as follows:
- Pulmonary veins - The only veins that transfer oxygenated blood from your lungs to the heart (right atrium)
- Deep veins - These are large veins located deep inside your muscles, usually next to a corresponding artery with the same name. They include the peroneal, deep femoral, popliteal, anterior and posterior tibial, superficial femoral, and iliac veins.
- Systemic veins - These veins are connected to every part of the body - tissues, organs - and carry deoxygenated blood back to the heart (right atrium)
- Superficial veins - Veins located near the surface of the skin which include the small saphenous vein (SSV), the great saphenous vein (GSV), and their tributaries
The internal diameter of a vein ranges from 1 to 15mm. The smallest veins are known as venules, and receive deoxygenated blood from various parts of the body via the arterioles and capillaries. Venules get bigger as they move towards the heart, until they reach the largest veins in the body connecting to the right atrium of heart, the inferior and superior vena cava.
The vein walls are relatively thin tissues comprising three layers:
- Tunica Adventitia - This tough outer skin of both veins and arteries is made of connective tissue and elastic and collagen fibers. These fibers allow blood vessels to expand without losing elasticity when blood pressure increases.
- Tunica Media - This middle layer is made of elastic muscle and fibers. It is thicker in arteries compared to veins.
- Tunica Intima - This inner layer is made of a smooth endothelium covered by elastic tissues. While arteries contain an elastic membrane lining inside, the inner walls of veins contain valves to prevent blood from flowing backwards.
Veins generally have thinner and more elastic walls than arteries, which allows them to transfer more blood.
Proper function and Complications
Most venous problems affect the veins in your legs, because they work the hardest pushing blood back to the heart against gravity. When the venous system is working properly, every muscle contraction pumps blood inward and upward through a series of valves. But due to inactivity, like prolonged standing, the veins experience difficulty pushing blood back to the heart. As a result, the vein walls expand and valves weaken.
When your valves become damaged and stop functioning properly, blood begins to pool and create varicose veins.
Vein Specialist in Ventura & Los Angeles
The Center for Vein Wellness specializes in vein treatments. Dr. Shah has a reputation for using state-of-the-art, minimally invasive treatments and quality care to resolve venous problems and give you the best possible outcomes.
When you visit the Center for Vein Wellness, Dr. Shah, a board-certified vein specialist will examine your problem areas, discuss your symptoms, and recommend an individualized treatment plan that address your specific needs.