The part of the circulatory system that brings blood, oxygen, hormones, nutrients, water and other substances throughout the body are called blood vessels. There are three major types of blood vessels, namely: arteries, veins and capillaries. The arteries carry blood away from the heart while the veins carry blood toward the heart. The capillaries are the smallest blood vessels which actually facilitate the exchange of chemicals and water between the blood and the tissues.
Blood vessels widen or narrow through the contraction of the muscular layer to accommodate the volume of blood flow. When the blood vessels become bigger or wider, it is called vasodilation. When blood vessels become smaller or narrow, it is called vasoconstriction. In both cases, blood flow is regulated by the autonomic nervous system. Related to this is the blood pressure which is the pressure applied by the circulation of the blood on the blood vessels. Blood pressure constantly changes depending on the condition, environment and activity of the individual. There is a determined normal blood pressure range. When blood pressure is lower or higher than normal, the blood vessels are consequently damaged.
It is important to have healthy blood vessels. Blockage in the blood vessels may lead to insufficient blood supply and consequently necrosis in that affected part of the body. Formation of lipid lumps or artherosclerosis may be fatal. A healthy lifestyle and diet, regular exercise and for some proper medication can help avoid the fatal consequences of damaged blood vessels.