Explain how these structures of the heart (right atrium, left ventricle, pulmonary valve, tricuspid valve, and valve tendons) assist in its function.

A heart is blood pumping organ which pumps blood continuously. A heart is made up of four chambers in which two atria and two ventricles are present. Right atrium collects deoxygenated blood with the help of vena cava from various parts of the body. Right atrium opens into the right ventricle through Tricuspid valve form right ventricle deoxygenated blood reaches to lungs through the pulmonary artery which consists of the pulmonary valve which prevents backward flow of blood. From lungs, oxygenated blood reaches to the left atrium through pulmonary vein. The left atrium opens into the left ventricle through the Bicuspid valve. From left ventricle oxygenated blood reaches to various parts of the body through the aorta. Valve tendons are connective tissue fibrous cords which connect papillary muscles to the tricuspid and bicuspid valve which play an important role in holding atrioventricular valves in their place while the heart is pumping the blood. The left ventricle is thickly walled which pumps oxygenated blood with high pressure to various parts of the body through the aorta.

The heart is one organ of the cardiovascular system. It functions as a pump, circulating blood to all parts of your body—including other organs, tissues, and cells—through vasculature consisting of arteries, capillaries, and veins. After blood travels through the veins, it is circulated back to the right side of the heart and then through the lungs to get oxygenated. This oxygenated blood then goes through the left side of the heart and pumped out to the rest of the body, and the cycle repeats. Realize that this system is so efficient that all steps occur essentially at the same time, though they will be explained in a step-by-step process.
The heart is a four-chambered structure, and blood flows as follows:

Superior Vena Cava --> Right Atrium --> Tricuspid Valve --> Right Ventricle --> Pulmonary Valve --> Pulmonary Artery --> Lungs --> Pulmonary Veins --> Left Atrium --> Mitral/Bicuspid Valve --> Left Ventricle --> Aortic Valve --> Aorta --> Rest of the body

The structures of these individual parts are essential in assisting their functions. For instance, all the valves are structured so as to only open one way. This is to prevent blood from "leaking" back where it came from, since doing so would decrease the efficiency of the circulatory system. Another great example of structure dictating function can be seen through understanding the left ventricle. The walls of the left ventricle are much thicker than the walls of the other three heart chambers. This is because the left ventricle needs to pump blood to your entire body! It needs those thick walls to provide lots of pressure to push all that blood to your body.