Heart Our Circulatory System Author:Seymour Simon The heart is a most incredible pump. About the size of a fist and weighing only about as much as one of your sneakers, in an average lifetime a heart will beat over two thousand million times without stopping for rest or repair. The heart pushes a stream of blood through sixty thousand miles of arteries, capillaries, and veins, a journey that ca... more »rries nutrients and oxygen to every cell in your body.In stunning photographs that will amaze you with their beauty and color, you will also learn about bacteria-eating white blood cells, blood-clotting platelets, and the spongy marrow tissue, where every second three million red blood cells are made.In The Heart, award-winning author Seymour Simon begins an exciting series that explores one of the most amazing mysteries in the universe-the human body. join him on a journey as strange and wonderful as any voyage to the stars.« less