The Cardiovascular System: A Closed Organ System In The Human Body

The cardiovascular system is a closed organ system that is found within humans and other vertebrates. The heart consists of the right and left ventricle, right and left atrium, aorta, capillaries, pulmonary arteries and veins and the anterior and posterior vena cava. All of the following structures maintain the heart's beating cycle and the circulation of blood throughout the body.
Three main types of blood vessels:
Arteries - Thick-walled tubes in which blood is brought from the heart to various parts of the body. Within these organs, the arteries turn into arterioles, which are smaller in size and bring blood into the capillaries.
Capillaries - A type of thin branching blood vessel with porous walls. Chemical diffuse between the blood and interstitial fluid found within the capillaries.
These chambers allow for blood to return to the heart, as well as a channel for blood to neighboring ventricles. These ventricles main function is to bring blood to the body’s organs.
When contracting, the heart begins to pump blood (Systole). On the other hand, while relaxing, the heart’s chambers will fill with blood (Diastole). This process is called the cardiac cycle.

Valves of the Heart:
Atrioventricular valve - A valve held together by strong fibers and is located in between the atrium and ventricle. While the heart is contacted, the ventricles close the atrioventricular valves. This keeps blood from flowing back into the atria.
Semilunar valves - A valve located at the exits of the heart. While the heart is contacted, the semilunar valves are forced to open. However when the ventricles are relaxed, blood begins to flow back into the heart. The semilunar valves function to prevent blood from getting back into the ventricles by closing.

Vena Cava
Superior Vena cava - Deoxygenated blood is brought from the upper section of the body and is brought back into the right