One-way "doors" that keep blood traveling in the right direction are called ______.
There are four valves - the aortic, tricuspid, pulmonary and mitral valves - that open and close in coordination with the pumping action of your heart. For your heart to work well, blood must flow in only one direction. Your heart's "in" and "out" valves, which have flaps to seal or open the valve, make that possible.
Asked by Pamela Ferdinand · Last updated 1 year ago · 739.6K views