英语听力文摘718 静脉血管的秘密
Veins are pretty important. After all, they carry blood from various parts of the body to the heart. But for all their significance, veins are modest, too. Yours are probably content to work behind the scenes, tucked away beneath the skin.
Twisted And Filled
Sometimes, however, veins take center-stage and become visible as blue lines on the skin, often resembling an unmarked roadmap. If you haven’t guessed by now, we’re talking about varicose veins. Have you ever wondered what are they are and how they form?
Basically, a varicose vein is one that is twisted and filled with backed-up blood. Although they most commonly occur in the legs, varicose veins can also happen in the esophagus, testes and the urinary bladder.
Varicose veins in the legs occur when the valves in a vein near the surface of the skin malfunction.
Faulty Valves
Valves usually keep blood from flowing backwards in the vein once it’s been pumped towards the heart. When the valves don’t work properly, blood gets stuck, causing the vein to swell and kink.
Although varicose veins are usually associated with senior citizens, not every older person has them. Weak valves are often inherited, and can also be caused by wearing clothing that squeezes the legs and veins too tightly.
Varicose veins may seem unsightly, but they’re not usually a cause for major concern. Still, if you have them and want to do something about it, talk to your doctor. Treatments range from wearing strong support stockings to surgery.
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