Circulatory System Crossword Puzzle

QUESTIONS LIST: arteries : blood vessels that carry blood away from the heart, cardiovascular : _ system consists of the heart, blood vessels, and blood, veins : blood vessels that carry blood back to the heart, pacemaker : a group of heart cells that sends out signals that make the heart muscle contract, capillaries : place where substances are exchanged between the blood and body cells, heart : hollow, muscular organ that pumps blood throughout the body, aorta : largest artery in the body, pulse : the alternating expansion and relaxation of the artery walls, blood pressure : a force exerted by blood against the walls of blood vessels, white : _ blood cells - the body's disease fighters, valve : a flap of tissue that prevents blood from flowing backward, ventricle : lower chambers of the heart, red : _ blood cells - take up oxygen in the blood and deliver it to cells elsewhere in the body, plasma : the liquid part of blood, atrium : upper chambers of the heart, hemoglobin : iron-containing protein that binds chemically to oxygen molecules, diffusion : the process by which molecules move from an area of higher concentration to an area of lower concentration