Abstract

My technical description paper is about the circulatory system, which includes three major parts, and its functions. The first part focuses on the heart, the central organ of the circulatory system, and the pathway of blood as it is pumped in the body. The second part is about the lungs, which is the site of gas exchange. It explains the mechanism of transferring oxygen into the red blood cells as well as removing carbon dioxide from it. The last part of the paper talks about the blood vessels as the transport system of the body. It is through these structures that blood reaches the different parts of the body.

The Circulatory System

            The circulatory system, also known as the cardiovascular system, delivers blood, oxygen, and nutrients to different parts of the body. Its function is essential to an individual’s survival. It involves three organ systems that work together to make this mechanism possible (Toro, “Diagram of the Human Circulatory System”). These include the heart, which is the major organ of the cardiovascular system, the lungs, which is the main organ of the pulmonary system, and the blood vessels, which act as the transport system in the human body.

THE HEART: STRUCTURE AND FUNCTION

                 Figure 1. Diagram of the human heart. Upload.wikimedia.org. n.d. Web.

Located slightly to the left of the breastbone, the average human heart weighs approximately 300 grams and is about the size of one’s fist (Toro, “Diagram of the Human Circulatory System”). It has four chambers: the right and left atria, and the right and left ventricles (See Figure 1). It also has four valves, the structure which prevents the backflow of blood. The right atrium receives deoxygenated blood (blood without oxygen) from the rest of the body through the superior and inferior vena cava. The blood then proceeds to the right ventricle via the tricuspid valve or the right atrioventricular valve. From there, the blood passes through the pulmonary artery and is transported to the lungs to be oxygenated. The pulmonary valve, also called the semilunar valves, prevents the backflow of blood to the right ventricle. After oxygenation, the blood is received by the left atrium and continues to the left ventricle via the mitral valve. The oxygenated blood (blood with oxygen) will then pass through the aortic valve and aorta, and then will be distributed to the rest of the organs in the body (Cleveland Clinic, “How Does the Blood Flow Through Your Heart”).

The heart also has three layers (Medicine LibreTexts, “Layers of the Heart”). The outer layer is called the epicardium. Within this layer is the pericardium, a membrane that protects the heart. The middle layer is the myocardium which comprises the heart muscle. Lastly, the inner most layer is called the endocardium.

THE LUNGS: SITE OF GAS EXCHANGE

 Figure 2. How does oxygen get into the bloodstream? blf.org.uk. n.d. Web.

Responsible for the exchange of gases in the body, the lungs are located on both sides of the heart. The left lung is slightly smaller than that of the right because it shares its space in the chest cavity with the heart (British Lung Foundation, “How Your Lungs Work”). The trachea, which is commonly called the windpipe, brings the air we breathe into the lungs. It splits into two branches called the bronchi, which in turn divides into much smaller tubes called the bronchial tree. Tiny air sacs named the alveoli are found at the end of the tree and these are the sites of oxygen and carbon dioxide exchange (refer to Figure 2).

Inside the alveoli, oxygen is transported across small blood vessels called capillaries and is taken up by the red blood cells (RBCs) via an oxygen-carrier protein called hemoglobin. Simultaneously, carbon dioxide in the blood stream is also exchanged from the capillaries into the alveoli. The RBCs with oxygen (oxygenated blood) is then transported back to the heart through the left atrium and will be pumped to the rest of the body through the arteries (British Lung Foundation, “How Your Lungs Work”).

THE BLOOD VESSELS: THE TRANSPORT SYSTEM OF THE BODY

Figure 3. The Circulatory System Review. openstax.org. n.d. Web.

While the heart pumps, blood is transported to different parts in the body through the blood vessels. There are three main types of blood vessels (Cleveland Clinic, “How Does Blood Flow Through Your Body”). The arteries carry oxygenated blood and nutrients from the heart to the organs and tissues of the body. An example of this vessel is the aorta, which is the artery that moves blood from the heart. Another type of blood vessel is the vein. In contrast to the arteries, the veins carry deoxygenated blood back to the heart. Examples are the superior vena cava and the inferior vena cava. Lastly, the capillaries are minute blood vessels that link the arteries and the veins. They are essential for the exchange of oxygen, carbon dioxide, nutrients, and waste products in the tissues (Cleveland Clinic, “How Does Blood Flow Through Your Body”).

SUMMARY

The heart, lungs, and blood vessels work together in a complex yet coordinated process. The circulatory system is a critical mechanism and a dysfunction in one of its components affects the entire body system. Certain diseases such as diabetes, chronic obstructive pulmonary disease (COPD), and heart failure can contribute to this decline in function. Therefore, utmost care is imperative for a well-functioning circulatory system and a healthy life.

 

Works Cited

British Lung Foundation. How Your Lungs Work. February 2018. www.blf.org.uk/support-for-you/how-your-lungs-work/oxygen-and-blood. Accessed 18 Sep. 2020

Cleveland Clinic. “How Does Blood Flow Through your Body.” www.my.clevelandclinic.org/health/articles/17059-how-does-blood-flow-through-your-body. Accessed 21 Sep. 2020

Medicine Libre Texts. “Layers of the Heart Walls.” 13 Aug. 2020. www.med.libretexts.org/Bookshelves/Anatomy_and_Physiology/Book%3A_Anatomy_and_Physiology_(Boundless)/17%3A_Cardiovascular_System%3A_The_Heart/17.1%3A_The_Heart/17.1C%3A_Layers_of_the_Heart_Walls. Accessed 19 Sep. 2020

Toro, Ross. “Diagram of the Human Circulatory System.” Live Science, 29 Aug. 2013, www.livescience.com/27585-human-body-system-circulation-infographic.html. Accessed 19 Sep. 2020

Villareal, Mariana Ruiz. Blood Vessels. www.openstax.org/books/concepts-biology/pages/16-3-circulatory-and-respiratory-systems. Accessed 18 September 2020.

Wikimedia. Diagram of the Heart. 2006. www./en.wikipedia.org/wiki/Heart#/media/File:Diagram_of_the_human_heart_(cropped).svg. Accessed 18 September 2020.