1530s, a running (usually at full speed), a course (especially of the sun, etc., across the sky), from Middle French carriere road, racecourse (16c.), from Old ProvenÃ§al or Italian carriera, from Vulgar Latin *(via) cararia carriage (road), track for wheeled vehicles, from Latin carrus chariot (see car).
Noun. 1. tricuspid valve-valve with three cusps; situated between the right atrium and the right ventricle; allows blood to pass from atrium to ventricle and closes to prevent backflow when the ventricle contracts. right atrioventricular valve.
Blood passes through a valve before leaving each chamber of the heart. The valves prevent the backward flow of blood. Valves are actually flaps (leaflets) that act as one-way inlets for blood coming into a ventricle and one-way outlets for blood leaving a ventricle. Normal valves have 3 flaps (leaflets), except the mitral valve, which only has 2 flaps. The 4 heart valves include: