I'm not going to fully write out <span>3-4 paragraphs but I will give you some information to start out with :) I greatly enjoy doing research and writing about the things I have learned.
Arteries: Arteries are </span>any of the muscular-walled tubes forming part of the circulation system by which blood (mainly that which has been oxygenated) is conveyed from the heart to all parts of the body. <span> Each artery is a muscular tube lined by smooth tissue and has three layers. These are the three layers and their purpose. *The i</span>ntima-T<span>he inner layer lined by a smooth tissue called endothelium </span>*The media- A<span> layer of muscle that lets arteries handle the high pressures from the heart *</span>The adventitia-Connective tissue anchoring arteries to nearby tissues
Veins<span> are </span>blood vessels<span> that carry </span>blood<span> toward the </span>heart<span>. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the </span>pulmonary<span> and </span>umbilical veins<span>, both of which carry oxygenated blood to the heart. In contrast to veins, </span>arteries<span> carry blood away from the heart. </span>Veins are classified in a number of ways, including superficial vs. deep, pulmonary vs. systemic, and large vs. small. <span> *Superficial veins are those closer to the surface of the body, and have no corresponding arteries. </span><span>*Deep veins are deeper in the body and have corresponding arteries. </span><span>*Perforator veins drain from the superficial to the deep veins. These are usually referred to in the lower limbs and feet. </span><span>*Communicating veins are veins that directly connect superficial veins to deep veins. *P</span>ulmonary veins<span> are a set of veins that deliver oxygenated blood from the </span>lungs<span> to the heart. *</span><span>Systemic veins drain the tissues of the body and deliver deoxygenated blood to the heart.
I hoped this helped and gave you some useful information. Good luck, I hope you do well on your assignment :) ~Sadie
Because, when an infection exist in the human body it tends to spread, so if the cells stayed in one space then the infection would have a much greater opportunity to severly make that person very ill before the cells could even get to the infection.