Human body is a magical machine

Published: Last Edited:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

Your human body is a magical machine. Throughout the years scientist and doctors have studied the structures and functions of the human body. The cardiovascular system, one of the eleven systems of the body, is perhaps one of the most effective, and interesting system of the human body.

The cardio vascular system is composed of the heart, blood, and blood vessels. The heart is a hollow organ located in between the lungs in the thoracic cavity. It functions as the pump of the cardiovascular system. The heart is composed of four chambers, two atriums, and two ventricles. The atria are the receiving chambers of the heart and are small in muscle size because they only deliver blood to the ventricles. The ventricles are the pumping chambers of the heart. They are more muscular than the atria, with the left ventricle being the thickest chamber because it pumps blood throughout the whole body. The heart is also has four valves.

Blood transports oxygen from the lungs to cells though out the body. Blood also carries carbon dioxide from the cells to the lungs. It also carries nutrients to body cells, and waste products away from cells.

Blood vessels transport blood from the heart to the cells and then back to the heart. “The network of blood vessels in a human being is not only extensive, it's also finely engineered. Some anatomists say that, placed end to end, the vessels would stretch 60,000 miles.” (Reebs 16) Arteries and arterioles carry oxygenated blood away from the heart. Capillaries connect arterioles and venules, and enable the exchange of water, oxygen, carbon dioxide and many other substances between cells and blood. Veins and venules carry deoxygenated blood back to the heart.

The right atrium fills up with deoxygenated blood. It receives the blood from three veins depending on where the blood came from in location of the heart. Blood coming from above the heart is transported to the heart through the superior vena cava. If the blood originated from below the heart the inferior vena cava carries the blood to the heart. The coronary sinus carries blood used to supply the muscles of the heart back to

the heart. After the right atrium is full of blood and the heart contracts the deoxygenated blood is pushed through the tricuspid valve into the right ventricle. The heart contracts the again and the blood is then pumped into the pulmonary trunk. The pulmonary trunk splits into left and right pulmonary artery which carries blood to the right or left lung. The carbon dioxide is then pulled from the blood and oxygen enters the blood. The resupply of oxygen all takes place in the pulmonary capillaries.

The oxygenated blood then travels to the left atrium through the pulmonary vein. After another heart contraction the blood is then pushed through the bicuspid valve to the left ventricles. The blood is then pushed through the aortic valve from another heart contraction. The blood then flows through the aorta and the pulmonary trunk.

The aorta then branches off into many arteries. The left and right coronary arteries supply the heart with oxygenated blood. The rest of the body is supplied by other arteries. The blood flows through the arties which branch off into smaller arteries called arterioles. The arterioles branch off into smaller vessels called capillaries.

Capillaries are microscopic blood vessels through which blood transfers oxygen and nutrients to the cells. Capillary blood pressure then pushes blood, oxygen, and nutrients out of the cells into the interstitial fluid. “Colloid osmotic pressure is generated across membranes that are permeable to water and low-molecular-weight substances but that are impermeable to large molecular compounds, such as plasma proteins.” (Camacho, Maria T, et al. 1655) and pulls the blood, carbon dioxide, and cell waste back into the capillaries.

Capillaries carrying deoxygenated blood merge into venules. Branches of venules drain the blood into veins. These midsized veins join to form the superior vena cava, coronary sinus, or inferior vena cava depending on their location. The deoxygenated blood then enters the right atrium.

The cardiovascular system pumps blood throughout the body. The heart acts as the pump for this system. “Beating almost 100,000 times a day… the heart is a muscle-perpetually pumping approximately five quarts of blood in a ceaseless circuit to deliver oxygen to every cell in the body.” (“Many Mysteries” 8) Blood is transported throughout the body in blood vessels: arteries, arterioles, capillaries, venules, and veins. Blood supplies the body with oxygen and nutrients and takes carbon dioxide away from the cells. This never ending cycle is one of many important cycles that keep us alive.

Anonymous. "The Many Mysteries of the Human Heart." USA Today Oct. 2007: 8. ProQuest. Web. 07 Apr. 2010.

Camacho, Maria T., et al. "Pulmonary and Extrapulmonary Effects of Increased Colloid Osmotic Pressure During Endotoxemia in Rats." Chest 120.5 (2001): 1655-663. EBSCOhost. Web. 07 Apr. 2010.

Reebs, Stephan. "In the Same Vein." Natural History 112.5 (Jun. 2003): 16. ProQuest. Web. 07 Apr. 2010.

Essay Memo

1. What was your purpose? What effect were you trying to achieve?

The purpose of this essay was to break down the components of the cardiovascular system. I also described how they work, and how they work in conjunction with the other components.

2. What was interesting about the process you went through in writing this paper, and what did you learn from it?

This essay helped me understand this week's assignment in Anatomy and Physiology. I learned how blood flows through the body and the heart.

3. What was the most difficult aspect about this paper, and what did you learn from the attempt?

The most difficult aspect was staying in the word count. I had to get rid of a couple of paragraphs to not exceed 700 words. I had to choose ones that I felt wouldn't take away form the assignment.

4. What do you see as the strengths of the paper, and what would you try to do if you were to revise it some more?

I like the flow of my paper. I might need to work on explaining the components of the cardiovascular system better. I have a pretty good grasp on the system but some of my readers might not. This paper might be a bit confusing to them.

5. What's not a part of your paper that you think might help a reader understand or appreciate it more? What didn't you put in?

I had to take out the paragraph about the SA node and how action potentials make the heart pump. I also had to cut man explanation short. I feel the reader might better understand the cardiovascular system better if I put them back in.

6. What kind of grammar or formatting feedback would you like from your instructor?

I would like to know if I messed up on anything.

7. When using the APUS Online Library article databases, did you evaluate the credibility of the sources you chose?

I did not evaluate the credibility of my sources but feel they are good sources.

8. Are your memo and essay in correct MLA format?

Yes, my memo and essay are in correct MLA format.

9. Did you save your file using your last name and the name of the assignment?


10. Are you free from contractions? Are you in the correct person? Never ever use second person ("you," "your," "yourself," etc.) in formal writing.

I am free from contractions and am in the correct person.