Veins…What are Veins?

All of us probably heard about blood and blood circulation. We are aware of the heart pumping blood throughout the body our whole life. Blood’s constant traveling brings oxygen and nutrients to the organs, and takes away waste products, including carbon dioxide.

The heart and the net of vessels, meaning arteries, capillaries and veins, is called the cardiovascular system. The simple concept of the circulation is that blood gets pushed out from the heart to the arteries, reaches body organs through capillaries, and directs its way back to the heart with the help of veins. The added length of our individual blood vessels could circle the globe more than two times. Daily, about 1,800 gallons of blood gets pumped out by the heart.

Arteries differ from veins.

Arteries are stiffed, high pressure tubes. They come out of the heart. Arteries, in the systemic circulation, deliver sources of energy to individual body cells. When somebody suffers a heart attack, it means that one of the heart’s own arteries becomes occluded. Subsequently blood cannot reach a smaller or bigger area of the heart, cells of the heart do not receive oxygen and then die.

Veins are more numerous. 64% of our blood volume is carried in the veins. They are soft, low pressure, slow motion, and very often visible through the skin. Veins make the blood return to the heart. They literally collect blood from the organs and bring it back to the heart. Their walls are very thin, elastic, and soft. Size 1mm to 1.5cm.

Blood moves through the veins not because of the pumping power of the heart. It rather relies on the concept of different pressure gradients.

Let us pause now. How does it then return from our legs? What power makes it go upward against the gravity?

Blood return from the legs is propelled by the leg muscles. When in motion (walking, exercising), our muscles contract, squeezing the veins. Blood gets pushed up towards the heart. In healthy veins, the blood does not reflux back upon muscle relaxation. Vein valves play a major role in the process.

Many veins, particularly those in the legs, have one-way valves. Each valve consists of two flaps with edges that meet. Blood, as it moves toward the heart, pushes the cusps open like a pair of one-way swinging doors. If the blood tries to pull backward, the cusps close, stopping backward flow. Valves help the return of blood to the heart—by opening when the blood flows toward the heart and closing when blood might flow backward because of gravity.

What happens when valves stop working, lose their function?

Leaky valves, what we call them, promote development of varicose veins. Sometimes very fast.

The blood flow is not directed towards the heart anymore. Valves do not stop the backward stream of returning blood, moving down towards the foot. Legs vein pressure increases. Veins become larger and larger, trying to accommodate the surplus of retained blood. Blood finds its way to smaller, subsequently enlarging superficial veins. Varicose veins form in a perpetuated manner.

Varicose vein may not be visible for years. Still hidden under layers of subcutaneous tissue and skin await to reveal themselves to our eyes.

Many of us, develop symptoms and signs suggestive of vein diseases many years before the veins become visible. Our legs happen to feel heavy and frequent cramps prevent a good night rest. Restless leg syndrome, often mentioned in the literature, can be caused by venous insufficiency. Skin color or texture changes, leading to ulcers, are the hallmark of increasing vein pressure in the legs. Legs often become swollen.

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