Blood vessel between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart. The word "vascular", meaning relating to the blood vessels, is derived from the Latin "vas", meaning vessel. A few structures (such as cartilage and the lens of the eye) do not contain blood vessels and are labeled. The arteries and veins have three layers. The middle layer is thicker in the arteries than it is in the veins: Capillaries consist of little more than a layer of endothelium and occasional connective tissue. When blood vessels connect to form a region of
Urinary bladder mediate bladder diseases such as overactive bladder. The bladder is supplied by the vesical arteries and drained by the vesical veins. The superior vesical artery supplies blood to the upper part of the bladder. The lower part of the bladder is supplied by the inferior vesical artery in males and by the vaginal artery in females, both of which are branches of the internal iliac arteries. In females, the uterine arteries provides additional blood supply. Venous drainage begins in a network of small vessels on the lateral and posterior surfaces of the bladder, which coalesce and pass backwards along the