Blood flows through the whole body and the heart via an intricate network of arteries and veins. The veins are exclusively responsible for the flow of blood towards the heart. In most cases, blood travels through the veins upwards, opposite to the force of gravity. In order to achieve this they have a one-way valve mechanism. Vein disease results when these valves become defective leading to varicose veins or spider veins. They either fail to function entirely or do not close completely, leading to the pooling of blood in the vein. Varicose veins are abnormal, dilated blood vessels that arise from weakened blood vessels. The blood pools and collects inside the vein leading to a bulge that is visible to the naked eye. Spider veins are thin red capillaries that are found around the varicose veins.
The best heart doctors in Long Island explain that weak vein walls are one of the reasons for the valves not functioning as they should. In normal veins, the walls are elastic. However, when the vein walls lose their elasticity, they become overstretched and the vein becomes wider. This causes the flaps of the valve to separate making it leaky. In this way blood flows backwards filling the vein and stretching it even more.