I also received a supposed to be coming from CiTi PO BOX 790040 St. Louis MO 63179-9819.It said account ending in XXXX has been sold to Midland Credit Management, INC. Midlan...
Veins have much thinner walls, because the blood they carry is under low pressure. VEINS have valves that aid the return of blood to the heart and prevent blood from going backwards. ARTERIES do not have valves, except for the semi-lunar valves of the pulmonary artery and the aorta. ARTERIES have relatively narrow lumens, VEINS have relatively wide lumens.
There are valves in veins to prevent backflow. The blood pressure in veins is relatively low and, particularly in the legs and arms, can tend to pool if allowed to backflow. I â¦ n contrast, there is relatively high blood pressure in the arteries, which prevents the need for valves to control backflow.rteries do not need them as the blood in them is being pumped out from the heart under pressure. The pressure it â¦ self prevents backflow. It is interesting to note that veins in the head and upper chest don't have valves either, because blood in them flows under gravity.