It has four main components: plasma, red blood cells, white blood cells, and platelets. The blood that runs through the veins, arteries, and capillaries is known as whole blood—a mixture of about 55% plasma and 45% blood cells. About 7% to 8% of your total body weight is blood. Blood is a liquid connective tissue made up of blood cells and plasma that circulate inside the blood vessels under the pumping action of the heart. In this Review series episode, Blood associate editor Dr. Diane Krause interviews contributing authors from the Review Series on Clonal tracking in Hematopoiesis published in volume 147 issue 23 of Blood. Blood is a fluid that transports oxygen and nutrients to cells and carries away carbon dioxide and other waste products. It contains specialized cells that serve particular functions. These cells are suspended in a liquid matrix known as plasma. Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells of the body, and transports metabolic waste products away from those same cells. [1] Blood is composed of blood cells suspended in plasma. The solid part of your blood contains red blood cells, white blood cells, and platelets. Red blood cells (RBC) deliver oxygen from your lungs to your tissues and organs. Blood is a specialized fluid that constantly flows throughout your body. It’s made of plasma, red blood cells, white blood cells and platelets. Detailed information on blood, including components of blood, functions of blood cells and common blood tests. Learn about blood types, including A, B, AB, O and Rh+ and Rh-. See which blood type is the universal donor and universal recipient. We recruit and collect blood, plasma and platelet donations at over 13,000 donation events every year. We have 35 permanent donor centres and over 4000 mobile donor centres across Canada.