普特听力短文：原来静脉血管是这样的

普特听力短文：原来静脉血管是这样的 【普特听力短文】 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 havent guessed by now, were 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 its been pumped towards the heart. When the valves dont 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 theyre 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. 参考译文： 血管相当的重要。毕竟，它们从身体的各个部分向心脏运输血液。虽然血管很重要，但是它们也很谦逊。血管甘愿在幕后工作，在皮肤下默默运输血液。 扭曲的并充满的 不过，有时候血管成为主角，在皮肤上能够看到蓝色的线，很像未被标记的地图。如果你还没有猜到，我们讨论的正是静脉曲张的血管。你是否想知道它们是什么并怎样形成的么? 通常，静脉曲张的血管充满回流的血液并所以扭曲。它们不但多见于腿部，也会表现在食管、睾丸、膀胱上。 当皮肤表面下的血管的阀门不起作用时，腿上的静脉曲张开始显现。 受损的瓣膜 阀门的作用是防止有心脏送出的血液回流。当阀门不正常工作时，血液不能流动，导致血管膨胀和扭结。 虽然静脉曲张多发生在老年人身上，但是不是每个老年人都患有这种病。脆弱的阀门通常是