Digestion  begins in the mouth with chewing and ends in the small intestine.  As food passes through the GI tract, it miâ¦xes with digestive  juices, causing large molecules of food to break down into smaller  molecules.
Tracing the flow of blood through the heart isn't as simple as it may seem. The heart is a complex organ, using four chambers, four valves and multiple blood vessels to provide blood to the body. The flow through the heart is equally complex, with blood moving through the heart, then the lungs, before returning again to the heart.
Rating Newest Oldest. Best Answer: I hope this helps: Mitral valve allows the blood to flow from the left atrium into the left ventricle. The tricuspid valve is the three flapped valve on the right side of the heart, between the right atrium and the right ventricle which stops the backflow of blood between the two.E: Valves that prevent backflow in the heart? What valve prevents back-flow into the left ventricle? What valve prevents back-flow into the right atrium? What valve prevents back-flow into the left atrium?