The facial vein has no valves
http://en.wikipedia.org/wiki/Facial_vein
Nothing, it is only pressure that keeps blood moving in the right direction in arteries. Veins have valves that prevent backflow of blood, but arteries do not.
veins have valves. y
Valves can be found in the heart aswell as the veins
The blood in veins is not under direct pressure from the heart. It has little valves inside to prevent blood from flowing backwards away from the heart. These valves inside the veins prevent the backflow of blood in veins. They encourage the one-directional flow of blood to the heart.
No; arteries (and arterioles) depend on smooth muscle contraction, whereas veins (and venules) have valves.
Veins. Veins are blood vessels that carry blood from tissues and organs back to the heart; they have thin walls and one-way valves.
Vena Cava has valves, if im not wrong, but pulmonary veins definitely do not have valves.
Veins have valves so the blood dosent backflow
Capillaries do not have valves. Veins are the blood vessels with valves.
The veins have valves in them
no
veins have valves because they bring blood from the bottom half of your body and valves stop the back flow of blood since the veins work against gravity.
valves
valves
Veins have one way valves because the pressure in veins is lower than that in arteries, and the valves prevent backflow that could be caused by gravity or muscle flexure.
valves in the veins
They are called valves, or leaflet valves in the veins, that interlock to prevent backflow of the blood.