How many veins are there in the human body?
It is widely known the fact that in the circulatory system, veins are blood vessels that carry blood toward the heart. Most veins carry deoxygenated blood from the tissues back to the heart. There are also some exceptions: the pulmonary and umbilical veins. It is important to know that these veins carry oxygenated blood to the heart. Not too many people know that vein color is determined in large part by the color of venous blood, which is usually dark red as a result of its low oxygen content. The main idea is that veins serve to return blood from organs to the heart.