First blood enters into the top right chamber, the right atrium, stop there for a moment then drops down into the bottom right chamber, the right ventricle. When your heart beats the used blood in the bottom right chambers shoots out of the heart and through an artery into you lungs.
indicator - (chemistry) a substance that changes color to indicate the presence of some ion or substance; can be used to indicate the completion of a chemical reaction or (in medicine) to test for a particular reaction.
indicator inÂ·diÂ·caÂ·tor (Ä­n'dÄ­-kÄ'tÉr) n. One that indicates, especially a pointer or an index. An instrument used to monitor the operation or condition of an engine, an electrical network, or another physical system; a meter or gauge. The needle, dial, or other registering device on such an instrument.