Grandparents have always been important. Today, they're even more important. In busy, two-career and single-parent families, an involved grandparent goes a long way to filling a void for children. In extreme situations, the courts have found it's often a grandparent who can reach a troubled teen when no one else can.
Here's how to enlarge your veins and arteries for plasma donation: 1  Heat up your arm. When veins become overheated, they expand, and draw closer to the skin. 2  Hold off on drinking and smoking. Both smoking and drinking alcoholic beverages makes veins and arteries smaller and harder. 3  Hold off on the caffeine.
Answer: Veins contain valves to prevent blood from flowing backward. This is necessary because the venous vessels are a low-pressure system and the blood must sometimes flow against gravity, particularly in the limbs.nswer: Veins contain valves to prevent blood from flowing backward. This is necessary because the venous vessels are a low-pressure system and the blood must sometimes flow against gravity, particularly in the limbs.