Atherosclerosis 1 What Causes Atherosclerosis? Victoria Rock AIUOnline
Atherosclerosis 2 AbstractIn this paper we will discuss the heart and its parts including the arteries, veins, and capillaries.We will also discuss the diseases Atherosclerosis and Lymphoma and the parts of the humancirculatory system they affect. We will further discuss which circulatory system is better, closedor open and why.
Atherosclerosis 3 What Causes Atherosclerosis? Atherosclerosis is a disease that affects the arteries of the heart. To understand howatherosclerosis may cause a heart attack, we must first understand how the heart works. The heart is made up of four parts, with arteries, veins, and capillaries coming off of it. Thefour chambers of the heart are; the left and right ventricles and the left and right atrium, whicheach have their part in providing life sustaining blood to all parts of the body. (Audesirk, 2008)The left and right ventricles are responsible for sending blood out from the heart, while the leftand right atriums are responsible for receiving blood and sending it to the ventricles to be sentout again. (Audesirk, 2008) The right atrium and ventricle, referred to as the pulmonary circuit, is responsible forproviding the lungs with nutrients, while the left atrium and ventricle, referred to as the systemiccircuit, is responsible for supplying nutrients to other organs in the body. The coronary circuitwhich is another important part of the heart provides blood with oxygen. (Ruck) To simplify, theright ventricle sends blood to the lungs, after being oxygenated the blood returns to the coronarycircuit where the oxygen and the blood is then sent to the left atrium. The blood is then pumpedfrom the left atrium into the left ventricle before being distributed throughout the body. Thearteries coming from the left ventricle carries the blood from the heart throughout the body toother organs, capillaries, forming a web-like network between arteries and veins, receive bloodfrom the arteries rich in oxygen, exchanging it for carbon dioxide from surrounding tissues andthen dumping the waste-rich blood out to the veins which then returns the blood back to the rightatrium where it is pumped back into the right ventricle and the cycle starts all over again. But ifthe arteries become clogged with fat, cholesterol, calcium, and other substances, it forms aplaque which builds up and hardens causing the arteries to be hard and be inflexible. This is
Atherosclerosis 4called Atherosclerosis disease. This is much the same way as if the pipes in your home becomeclogged with grease, food, and hair. When the water can’t flow through, it causes your sinks,tubs, and toilets to back up. The only difference with arteries is that if the blood can’t go backthrough to heart, it dies from lack of blood and oxygen. (Ruck) Difference between Arteries, Veins, and Capillaries Arteries, Veins and Capillaries are not that much different from each other. They are allblood vessels that carry blood through the body. Their differences are in their size and directionin which the blood flows: Arteries are fairly large, elastic muscular tubes that carry blood away from the heart to other body tissues. They are three layers thick in order to withstand the high pressure of blood being pumped directly from the heart, and are the strongest of the three kinds of vessels. (Audesirk, 2008) Veins, like arteries, have three layers but are not as thick or tough as the arteries. Veins contain valves in them to ensure that blood flows in one direction and doesn’t pool up in the legs. Veins carry blood from the tissues back to the heart and run parallel to the arteries throughout the body. (Audesirk, 2008) Capillaries are thin and fragile, being only one epithelial cell thick and so tight that blood cells can only flow single file through them. Capillaries are present near almost everybody cell and re known as the exchange vessels because they allow the exchange of nutrients and waste between the body’s cells and the blood. They form a web-like network between veins and arteries. (Audesirk, 2008)
Atherosclerosis 5 Advantages of having a closed circulatory system over an open one Before deciding the advantages of having a closed circulatory system over an open circulatorysystem we need to understand what each are: An open circulatory system is a system in which the heart pumps blood into the hemocoel which is positioned between the ectoderm and endoderm. With the open system, the blood flows into an interconnected system of sinuses so that the tissues receive nutrients, fluid and oxygen directly. With the open system blood volume is high. (Ruck) In a closed circulatory system blood flows from arteries to capillaries and through veins. The tissues surrounding the vessels are not directly bathed by blood. A closed system allows more of a complete function and blood volume is low. There is a variety of reasons why the closed circulatory system has advantages over the opencirculatory system. One reason is that every cell is at maximum with only two or three cellsdistance from a capillary. With closed circulatory there is the ability to have incredible controlover oxygen delivery to tissues. A unique characteristic is the process of ultra filtration in bloodcirculation. Also since the lymphatic system is included as part of the circulatory system with itscirculation of excess fluid and large molecules, it decreases the pressure in tissues that extra fluidincreases. Another important advantage is the systemic and pulmonary branches of the systemcan maintain their respective pressures. (Ruck) The Lymphatic System The lymphatic system works in conjunction with the circulatory system. It collects tissuefluid, kills foreign organisms, and returns it to the circulatory system. This system also preventstissue fluid from accumulating in the tissue space. Lymph capillaries, pick up the intercellular
Atherosclerosis 6fluid and carries it into larger lymph vessels where lymphocytes attack viruses and bacteria, itthan transports lymph to the larger brachiocephalic veins where it re-enters the circulatorysystem. (The lymphatic System) Much like arteries and the disease atherosclerosis, a blockage in the arteries, the lymphaticsystem can get a similar disease called lymphoma, which is a blockage in the lymphatic vessels.Lymphoma’s symptoms are swelling as a result of the obstruction of lymphatic vessels or lymphnodes, and the accumulation of large amounts of lymph in the affected region. With the inabilityto drain fluid properly, resulting in excess fluid in parts of the body, usually the arms or legs,patients with lymphoma have a higher risk of infection complications because their lymphocylescannot reach parts of the body where the swelling occurs. (What Is Lymphedema? What CausesLymphedema?, 2010) Conclusion The human system is a very complex, yet a simple system, much like the cars we drive, needregular maintenance to keep them running smoothly. With proper diet and exercise andfollowing our doctor’s orders, we can prevent many of the diseases like arthrosclerosis andlymphoma.
Atherosclerosis 7 ReferencesAtherosclerosis. (n.d.). Retrieved September 15, 2011, from University of Maryland Medical Center: www.umm.edu/altmed/articles/atherosclerosis-000016.htmAudersirk, T. (2011). Chapter 36: Defenses Against Disease. In T. Audersirk, Biology:Life on Earth with Physiology (9th Ed.) (pp. 691-712). San Franciso: Benjamin Cummings.Audesirk, T. (2008). Chapter 32: Circulation. In T. Audesirk, Biology-Life on Earth with Physiology (9th Ed.) (pp. 619-639). San Franciso: Benjamin Cummings.Ruck, B. (n.d.). Circulatory System. Retrieved September 16, 2011, from Saint Michaels College, Colchester, VT:www.cartage.org.lb/en/themes/sciences/zoology/animalphysiology/circulatorysystem/circulatorysystem.htmThe lymphatic System. (n.d.). Retrieved September 17, 2011, from Circulatory System-The Lymphatic System and The Circulatory System: science.jrank.org/pages/1500/Circulatory-System-lymphatic-system-circulatory- system.htmlWhat Is Lymphedema? What Causes Lymphedema? (2010, March 2). Retrieved September 17, 2011, from Medical News Today: www.medicalnewstoday.com/articles/180919.php