Properties of veins y Thin wall Some have valves to prevent back-flow of blood Weak ability to contract even if there are muscle fibers in the wall Dependant on" pumping action of surrounding muscles-particularly of the limbsProperties of veins ➢ Thin wall ➢ Some have valves to prevent back-flow of blood ➢ Weak ability to contract even if there are muscle fibers in the wall. ➢ Dependant on “pumping action of surrounding muscles – particularly of the limbs