Varicose Veins
Nadia Cowan
HOW varicose veins form
The weak and damaged veins are a result of blood leaks. Valves in the veins regulate the flow of blood and when valves are weakened, blood leaks through them and collects in the next segment of the vein. As blood collects, veins get backed up, causing them to swell and twist, creating the varicose vein.
WHY aren't there varicose arteries
While veins have valves, arteries do not. This prevents any buildup in valves because they simply do not exist. They don't need valves because the pressure in arteries is high enough to push blood without them. Arteries are thicker, so they're harder to stretch in general, and if they happened to get enlarged, one would not be able to tell because the're farther within the skin.
HOW blood returns to the heart
Since veins have a lower pressure, it seems like it would be difficult for them to return blood to the heart. They need a strong pressure to prevent blood pooling. When you breathe using the respiratory system, the diaphragm goes down in your chest, increasing pressure in the abdomen. This pressure forces blood back to the heart. This process is called the venous pump.
Also, skeletal muscle from the muscular system contracts when the body does physical activity with the help of the bones in the skeletal system. This increase in pressure as a result of exercise causes the heart to pump faster and harder. The increase in blood pressure makes it easier for blood to return to the heart.