The heart is one of the four vital organs of the human body (Sampson, 2020). It is the most important organ of the circulatory system and works as a pump to push blood to the organs, tissues, and cells within the body. The circulatory system consists of the heart and blood vessels (Seladi-Schulman, 2020). The circulatory system works in conjunction with the lungs to provide oxygen to blood. The heart pumps freshly oxygenated blood to the body through blood vessels and the blood gets returned to the heart through venules and veins ("Heart Information Center," 2020).

The heart sits between the two lobes of the lungs in the middle of one's chest. It is behind and slightly to the left of the breastbone, also known as the sternum. The reason for the heart being slightly to the left of the body is because the heart's bottom-left chamber, the left ventricle, is responsible for pumping oxygenated blood around the body. Thus, the bottom left of the heart has to be stronger and larger than the right ventricle, which only pumps blood to the lungs ("Why is the Heart," 2020).

Since the heart is a very important organ, it has a protective layer. The double-layered membrane is known as the pericardium. It surrounds the heart like a sac and has an outer and inner layer. The outer layer surrounds the roots of the heart's major blood vessels and is attached by ligaments to the spinal column, diaphragm, etc. The inner layer is attached to the heart muscle. A coating of fluid separates the two layers of the membrane and this allows the heart to move as it beats ("Heart Information Center," 2020).

The vital organ has four chambers: two upper chambers called atria and two lower chambers called ventricles. Humans are the most highly evolved mammal and thus, the complex structure of the heart has a distinct advantage over simpler structures. The four chambers allow the heart to send the "dirty" blood to the "cleaners," which are the lungs, and then the "clean" blood that comes out of the lungs goes to the rest of the body. Not once do the "dirty" and "clean" blood mix. This method allows humans to process energy more efficiently and thus, allows humans to move around more and move further from their source of fuel (Roizen, 2020). Blood flows into the right atrium from the veins of the heart and body. It then flows into the right ventricle to the pulmonary artery, where it travels to the lungs and gets oxygenated. The oxygenated blood then travels from the lungs, through the pulmonary veins, to the left atrium and eventually, the left ventricle. The blood then gets transferred to various body parts ("Heart Information Center," 2020). The left/right atrium and left/right ventricles are separated by the septum, a wall which prevents mixing of blood between the two sides of the heart ("Ventricular Septal Defect," 2020).

Furthermore, the heart has four valves that ensure that blood flows in the right direction. These are the tricuspid valve, the pulmonary valve, the mitral valve, and the aortic valve. The tricuspid valve regulates blood flow between the right atrium and right ventricle. The pulmonary valve controls blood flow from the right ventricle into the pulmonary arteries, which carries blood to the lungs to pick up oxygen. The mitral valve lets oxygen-rich blood from the lungs pass from the left atrium into the left ventricle. Lastly, the aortic valve opens the way for oxygen-rich blood to pass from the left ventricle into the aorta, which is the body's largest artery. The aorta is the main artery that carries blood away from the heart to the rest of the body ("Heart Information Center," 2020). The blood travels in a cane-shaped curve that allows other major arteries to deliver the oxygen rich blood to the brain, muscles, and other cells ("Your Aorta: The Pulse of Life," 2021).

The heart is a fascinating organ! It is only a little larger than one's fist and weighs between 7 to 15 ounces, yet it plays a crucial role in your well being and never stops working. In fact, by the end of one's life, a heart may have beat more than 3.5 billion times (Watson, 2009). It is crucial to take optimal care of one's heart. You only get one and it does everything in its power to keep you alive. Take a look at the other articles the Medical Science Club has written to inform you on how to best take care of your heart!

Works Cited:

1. "Heart Information Center: Heart Anatomy." Texas Heart Institute, 30 Sept. 2020, www.texasheart.org/heart-health/heart-information-center/topics/heart-anatomy/.
2. Roizen, Michael. "Why Do Our Hearts Have Four Chambers?: Heart and Circulatory System." Sharecare, www.sharecare.com/health/circulatory-system-health/why-hearts-have-four-chambers#:~:text=The%20four%2Dchambered%20heart%20has,That%20system%20is%20very%20efficient.
3. Sampson, Stacy, and Zawn Villines. "Organs in the Body: Diagram and All You Need to Know." Medical News Today, MediLexicon International, 2020, www.medicalnewstoday.com/articles/organs-in-the-body#non-vital-organs.
4. Seladi-Schulman, Jill, and Payal Kohli. "What Makes Up Your Circulatory System and How Does It Work?" Healthline, Healthline Media, 17 Feb. 2020, www.healthline.com/health/circulatory-system.
5. "Ventricular Septal Defect (VSD)." Adult Cardiothoracic Surgery - Ventricular Septal Defect, 2020, adultctsurgery.ucsf.edu/conditions--procedures/ventricular-septal-defect.aspx#:~:text=Your%20heart%20has%20two%20sides,inner%20wall%20called%20the%20septum.&text=The%20left%20side%20of%20your,two%20sides%20of%20the%20heart.
6. Watson, Stephanie. "Five Amazing Facts About the Human Heart." WebMD, WebMD, 2 July 2009, www.webmd.com/heart/features/amazing-facts-about-heart-health-and-heart-disease_#:~:text=Male%20heart%20attack%20symptoms%2C%20female%20heart%20attack%20symptoms&text=For%20instance%2C%20a%20man's%20heart,heart%20weighs%20approximately%208%20ounces.
7. "Why Is the Heart Slightly to the Left in the Chest?" BBC Science Focus Magazine, 2020, www.sciencefocus.com/the-human-body/why-is-the-heart-slightly-to-the-left-in-the-chest/#:~:text=This%20is%20because%20the%20heart's,feel%20beating%20in%20your%20chest.
8. "Your Aorta: The Pulse of Life." Www.heart.org, 2021, www.heart.org/en/health-topics/aortic-aneurysm/your-aorta-the-pulse-of-life#:~:text=The%20aorta%20is%20the%20main,brain%2C%20muscles%20and%20other%20cells.