In general we call it a blood vessel. Those which carry blood away from the heart are arteries, those which take it back are veins, and the tiny, thin-walled tubes which are found in the organs and exchange substances with the cells are capillaries.
"vessel"
Can be veins, can be arteries, can be capillaries, can be the aorta..
Blood vessels - arteries, capillaries and veins.
urethra
fallopian tube
It travels through a "Pipe" and explodes out the "Vent", or possibly the "Side Vent", and another world for the hole at the top is the Crater.
They breathe through their nose/mouth, where oxygenated air travels down their trachea (tube to lungs) and ends up in capillaries in their lungs, where "used" (deoxygenated) blood diffuses with the new blood.
Urine travels through the urethra to leave the body. The urethra connects the bladder to the exterior of the body.
An artery that is patent is an open tube. Blood will not flow through a closed tube.
The barrel of a firearm is the tube through which a bullet travels when a gun is fired.
they are blood vessels .they are of two types - arteries ,veins
Proboscis
Heart-->Aorta/Pulmonary Artery-->Arteries-->Arterioles-->Capillaries-->Venules-->Veins-->Vena Cava/Pulmonary Vein-->Heart