Veins
Term
Veins are blood vessels that return blood to the heart. Blood changes color depending on the oxygen saturation, so veins appear bluish. Venous insufficiency is a condition where blood flow through the veins is reduced. Veins are capacitance blood vessels that contain about 64% of the total blood volume in the body. These blood vessels are very elastic, able to accommodate additional blood volume with little change in pressure, i.e. they serve as blood reservoirs.
Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė