This action causes mucous to discharge from the nose and may run down the back of the throat in order to prevent these substances from causing infection or irritation. Runny nose may be triggered by other conditions such as allergies, a cold or the flu, infections or particular medicines.
The largest veins in the human body are the venae cavae. The superior vena cava carries blood from the arms and head to the right atrium of the heart. The inferior vena cava carries blood from the legs and abdomen to the heart.n the circulatory system, veins (from the Latin vena) are blood vessels that carry blood toward the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart.
What are Varicose Veins? Veins are blood vessels that return deoxygenated blood from the outer parts of the body back to the heart and lungs. When veins become abnormally thick, full of twists and turns, or enlarged, they are called varicose vein. This happens most commonly in the veins in the legs and thighs. 1  The thickened, twisting or dilated parts of the vein are called varicosities. 2  Varicose veins can form anywhere in the body, but they are most often located in the legs. 3  Varicose veins tend to be inherited, and become more prominent as a person ages.