Blood Cells are Produced in Bone Marrow Red cells, white cells and platelets are made in the marrow of the bones, especially the vertebrae, ribs, hips, skull and sternum. Plasma Carries Blood Cells Plasma is a pale yellow mixture of water, protiens and salts. One of the functions of plasma is to act as a carrier for blood cells nutrients.
	Red Cells Deliver Oxygen Red cells are disc-shaped cells containing hemoglobin, which enables the cells to pick up and deliver oxygen to all parts of the body.
White Cells Defend the Body White cells are the body's primary defense against infection. They can move out of the blood stream and reach tissues being invaded. Platelets Help Control Bleeding Platelets are small cells in the blood that control bleeding. They form clusters to plug small holes in blood vessels and assist in the clotting process.