And when the right atrium contracts, the blood passes through the tricuspid valve, into the relaxed right ventricle, and right back to where we started.
That being said, that contraction pumps the blood out the pulmonary valve, which just like the tricuspid valve has three cusps and also prevents blood from going backward.
Making our way down, between the fourth and fifth rib, next to the left lower border of the sternum, is where you can best hear the tricuspid valve closing.
For example, the right and left atria are both full of blood, and that blood moves through the tricuspid and the mitral valve to get down into the ventricles.
Right after the S2 sound, the tricuspid and mitral valves open back up allowing blood to fill up the ventricles again and this period of time is called diastole.
When the ventricle is filled, it contracts, forcing the tricuspid valve to close and forcing the blood through the pulmonary semilunar valve on its way to the lungs.
The impulses leap across synapse-like connections between the cells called gap junctions, and continue down the conduction system until they reach the atrioventricular node, or AV node, located just above the tricuspid valve.
On the other side of the heart, a tricusoid valve regurgitation has similar timing and shape, but it is loudest in the tricuspid area and the sound radiates up, along the left sternal border.
That first heart sound, " lub" , is called S1, and the noise comes from the tricuspid and mitral valves snapping shut when the left and right ventricles contract, which happens at about the same time.
When the ventricles contract, blood in the right ventricle is forced through the pulmonary semilunar valve into the pulmonary artery; at the same time, the tricuspid valve closes to prevent the backward flow of blood into the atrium.