the circulatory system All of the body's organs and tissues are supplied with oxygen and nutrients by the vascular system, commonly known as the cardiovascular system. It is made up of a network of interconnected blood vessels (veins and arteries) that are connected to the heart and lungs. One of the most important systems in the body is the vascular system. Because of this, illnesses affecting the circulatory system can significantly impair many dimensions of health. in fact Damage to the vascular system is a prevalent cause of many of the most severe illnesses, including stroke, dementia, heart disease, and diabetes.