The Human Heart Essays

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Introduction In our world organisms occupy a sliding scale of complexity. On one hand we have the single cell organisms, where all necessary functions for their life are carried out within that one cell. At the other extreme we have extremely complex multicellular organisms, of which humans are perhaps the cardinal member. Obviously, with increased capacity comes increased abilities. Complex organisms are able to manipulate their environment to a greater extent then their simpler cousins. While this has a lot of advantages, it also presents interesting biological problems. With the increased complexity multicellular organisms must have systems to deliver nutrients, signaling molecules, and biochemical building blocks to every cell. In…show more content…
While contraction in skeletal muscle is triggered by motor neurons under central control, certain cardiac muscle variants exhibit autorhythmicity. This means that that they are capable of producing their own depolarizing electrical potential. The cardiomyocytes that are capable of producing their own electrical potentials are found in what is referred to as the electrical condition system of the heart. This system is comprised of specializes cardiomyocytes that are autorhythmic and are able to conduct electrical potentials rapidly. These specialized structures include the sinoatrial node, atrioventricular node and bundle, and Purkinje fibers. While the bulk of the heart is myocardium, there are structural components that are pertinent. The four cardiac valves can be seen in a transverse section of the heart at the base of the ventricles.

Figure - grey’s cardiac skeleton

Surrounding each of these valves are dense fibrous rings or annuli made of connective tissue that forms the cardiac skeleton. The annuli of the aortic valve forms the base for the other annuli as it is located central to the other valves. Fibrous extensions from the annuli of the aortic valve extends outwardly and anchors the other three valves. In addition to the four annuli there are other fibrous components of the cardiac skeleton such as the right and left fibrous trigones, and the membranous septum. The right fibrous trigone is also know as the central
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