The circulatory system is important in meeting the needs of all cells in the body because it offers means of transport by which cells obtain the materials needed to live and function. The functions of the circulatory system by which the cells are supported include: 1. Respiration- oxygen is delivered to the cells and carbon dioxide is removed from them. 2. Nutrition- nutrients for energy are supplied to every cell in the body. 3. Waste removal- metabolic waste products are taken away before they accumulate and become harmful to the cells. 4. Cellular communication- hormones are transported to the cells and organs that need them for proper functioning. 5.Thermoregulation- As blood circulates, it keeps body temperature balanced and thus cells are able to carry out processes well.