Environmental program Essay Example for Free

Environmental program Essay Superfund is an environmental program formed to address abandoned hazardous waste sites. It is also established by the amended Comprehensive Environmental Response, Compensation and Liability Act of 1980. The law was enacted in the height of the discovery of dumps of toxic wastes in the 1970. The law permits the Environmental Protection Agency (EPA) to clean up such hazardous locations and to require responsible companies/persons to do clean up or compensate the government for EPA-initiated cleanups. The Superfund cleanup procedure is intricate. It starts on the assessment of the sites and placing them on the National Priorities List, then conduct cleanups on them. Located at 4109 West Linebaugh Avenue in Tampa, Hillsborough County, Florida, the Southern Solvents, Inc. served as a delivery and trade point for tetrachloroethylene. The chemical, which is also known as perchloroethylene or PCE was stored in four aboveground storage tanks in the facility from 1977 to 1985. The facility distributed the chemicals for dry cleaners located within the area. From 1985 to 1989 the facility was leased to P. J. ’s Spa and recently leased to a commercial painting company. The whole property of Southern Solvents, Inc. is about 100 feet wide and 185 feet deep. When the company is still in operations, the aboveground tanks were individually filled from tanker tanks that brought the chemicals to the facility. One former tank had a capacity of 3,000 gallons while the size of the other three is still unknown. It is believed that leaks and spills of tetrachloroethylene happened while the tanks are being filled and emptied. The tetrachloroethylene that spilled and leaked was not contained and eventually goes down into the nearby sandy soil. In 1988, when the facility’s drinking water well and several private drinking wells nearby, it was positive contamination of tetrachloroethylene and related compounds of trichloroethylene and 1,2-dichloroethan. The Florida Department of Health and Rehabilitative Services advise instantaneously the residents within the area to stop using water from these wells and supplied bottled water to owners and tenants in the area. The Florida Cites Water Department and the Northwest Hillsborough County Utilities have four wells that draw water from an aquifer within 4 miles of Southern Solvents facility. They provide water supply to more than 46,000 people in St. Petersburg, Hillsborough County, and nearby communities. As early as 1994, EPA conducted preliminary assessment of the site and its threat to the community. On July 27, 2000, Southern Solvents site was placed on the National Priorities List (NPL). Various studies then undergoes since the signing of the Superfund Contract that commits the State for 10 percent of the cost for the clean up. Until now, there are only initial steps of chemical oxidation studies and soil vapor extractions are done into the site. Reference: Environmental Protection Agency, Florida. (2009, March 20). Southern Solvents. Retrieved March 24, 2009, from http://www. dep. state. fl. us/waste/quick_topics/publications/ wc/sites/summary/141. pdf Environmental Protection Agency, United States. (2009, January 30). Superfund. Retrieved March 24, 2009, from http://www. epa. gov/superfund/about. htm

Anatomy And Physiology Of Blood And Heart

Anatomy And Physiology Of Blood And Heart The mechanism of the pumping action of the heart can be categorized in three phases- the generation of an action potential, conduction of the action potential and cardiac muscle contraction (action potential-contraction coupling). The action potential is generated the specialized autorythmic myocardial cells located at the Sino atria (SA) node. The potential spreads to the atria and enters the ventricles through the atria ventricular (AV) node from where it is conducted throughout the ventricles by the bundle of His and the purkinje fiber. The action potential triggers muscle contraction as it sweeps around the heart1. As the cardiac muscles contract and relax the heart beats repeatedly, in the process receiving and pumping blood, first to the lungs then to the rest of the body. As it leaves the heart, the blood carries with it oxygen and nutrients to the body and brings back metabolic wastes from the body cells1,2. However, much as it supplies blood to the rest of the body, the heart itself needs blood to support its metabolic activity. The heart is thus supplied by the coronary arteries which branch off from the aorta. Reduction in the volume of this coronary flow can greatly impair the pumping action of the heart and if not treated, can cause heart failure. A number of treatment options ranging from surgical to drugs are available2b. THE CARDIOVASCULAR SYSTEM The cardiovascular system is an organ system responsible for distribution of nutrients and oxygen to the bodys cells and removal of metabolic byproducts from the cells. It consists of the following: Blood which carries nutrients and oxygen to the cells and metabolic byproducts away from the cells The blood vessels which are the pathways through which blood flows The heart which receives and pumps blood. Embedded in the heart are valves that control blood flow and ensure that blood flows in a specified direction3,8. THE HEART In brief, the heart is a muscular organ enclosed in a double walled sack called the pericardium. It is about the size of a fist and weighs between 250 grams and 350 grams. It is located within the medial cavity of the thorax between the second and fifth intercostal space, just on the superior surface of the diaphragm, anterior to the vertebral column and posterior to the sternum7. The heart is divided in four chambers, the right and left atria, the right and left ventricle. The circulation process is such that the right atrium receives blood from the rest of the body through the venacavea and feeds it to the right ventricle which pumps it to the lungs through the pulmonary artery to be oxygenated. Blood from the lungs comes back to the left atrium through the pulmonary vein and finally to the left ventricle. The left ventricle pumps blood to the rest of the body though the aorta and arteries7,1. The Mechanism of Heart function The most important function of the heart is to pump blood. The mechanism by which the heart pumps blood can be understood by examining the events that lead to cardiac muscle contraction. The contraction process starts with the generation of an action potential from the sinoatrial (SA) node giving rise to a depolarization wave. The wave spreads through the atria, entering the ventricles through the atrioventricular (AV) node and is conducted throughout the ventricles by the bundle of His and the purkinje fibers1. Generation of action potential. The heart is composed of two kinds of cardiac muscle cells- the contractile and autorythmic cells. The contractile cells are responsible for the mechanical work of pumping and therefore form the bulk of the cardiac muscles. However, these cells need to be excited before they can contract. Highly specialized autorythmic cells are responsible for generation and conduction of the excitation signal-the action potential1,3. These autorythmic cells are found in specific regions of the heart that include: The SA node. This is a small region located at the upper wall of the right atrium. The AV node. This is a bundle of the autorythmic cells found at the lower wall of the right atrium, near the septum that separates the atria from the ventricles. The bundle of His. This is a bundle of specialized conductive cells that originate from the AV node and runs down the septum between the ventricles. It separates into the right and left bundles serving the respective ventricles. The purkinje fiber. These can be regarded as terminations of the bundle of His. They spread over the base of the ventricles.The locations of the autorythmic cells are the origin and pathways of the action potential3. The cardiac action potential The SA node is the pace maker of the heart. It sets the frequency at which the heart beats. Looking at the cardiac cell, the action potential starts by the reorganization of the intracellular and extracellular concentration of potassium, sodium, chloride and calcium ions due to changes in the cell membrane permeability. A graph showing a typical myocardial cell action potential is shown in figure 1 below. Figure 1: Cardiac cell action potential. Source4: As in the graph, the different phases represent different stages of depolarization of the cardiac cell. Phase 4: In this phase, the cell is at rest. In the resting state, the cell membrane is more permeable to potassium and therefore the resting potential is more or less equal to the potassium equilibrium potential (-90mV). Phase 0: As the potential slowly rises, the voltage-gated sodium channels open leading to a rapid influx of potassium into the cell causing rapid depolarization. At the same time, the membrane permeability to potassium slowly reduces as the potassium channels close. This process takes the membrane potential to around +20Mv before the sodium channels suddenly close. Phase 1: On inactivation of the sodium channels, potassium continues to leak out of the cell and chloride ions go into the cell causing a small downward deflection of the action potential. Phase 2: At this stage, there is increased permeability of the membrane to calcium ions. The inward calcium movement is balanced by an outward movement of potassium ions accounting for the relatively flat phase 2. Phase 3: An increase in the permeability of potassium outweighs the inward calcium current and eventually tips the potential of the cell. This is the repolarization phase and the cell goes back to its resting potential, phase 43,4. Excitation-contraction coupling As described in muscle contraction, the action potential-contraction coupling is due to the release of calcium from the cells sarcoplasmic reticulum. The calcium combines with troponin which regulates the tropomyosin, removing it from the binding site. This allows myosin to bind to actin thus making the muscle to contract3. The cardiac cycle The depolarization and repolarization of the cardiac cell described above triggers the contraction and relaxation to the atria and ventricles of the cell. The cardiac cycle is divided in two main phases, diastole which is the period of relaxation and systole which is the period of contraction. Systole. During this phase, the depolarization wave starts from the SA node, spreading first through the atria and causing the atria to contact first. This forces blood from the atria to the ventricles. At this time, the atrioventricular valves are open while the pulmonary and aortic valves are closed. The depolarization wave then enters the ventricles through the AV node, spreading over all the ventricles via the specialized conductive bundle of His and the purkinje network. This causes the ventricles to contract forcing the blood to the lungs through the pulmonary vein and the rest of the body through the aorta. Here the atrioventricular valves close while the pulmonary and aortic valves open5,3. Diastole. After contraction of the atria, the cells are repolarized. This allows the atria to relax thus allowing blood to flow into them through the vena cavea. After the ventricular contraction, the ventricles also relax awaiting to be filled with blood from the atria5. THE CIRCULATORY SYSTEM The circulatory system is part of the cardiovascular system and is divided into the pulmonary circulation and systemic circulation. The pulmonary circulation transports deoxygenated blood from the heart to the lungs and returns oxygenated blood from the lungs to the heart9. The systemic circulation transports oxygenated blood from the heart to the rest of the body and brings back deoxygenated blood from the body back to the heart9. Deoxygenated blood enters the right atrium from the vena cava and flows through the tricuspid valve into the right ventricle. It is pumped from the right ventricle through the pulmonary semilunar valve into the pulmonary arteries which go to the lungs. Oxygenated blood returns via the pulmonary veins and enters the left ventricle through the mitral valve. It is the pumped through the aortic valve, to the aorta then through the arteries to the rest of the body. It is evident that oxygen is very important in metabolic activity of the body cells3,9. Transport of oxygen by the cardiovascular system The red blood cells. One of the functions of the cardiovascular system is to distribute oxygen around the body. Oxygen is carried in blood by the red blood cells. Understanding the structure of the red blood cells will help us to understand how it is able to carry oxygen. The molecule of a red blood cell is composed of four polypeptide chains with each polypeptide chain having an iron-containing heme group. Each of the four iron atoms can combine reversibly with oxygen according to the equation: O2+Hbà ¢Ã¢â‚¬  Ã¢â‚¬ HbO2. It is therefore possible that each molecule of hemoglobin can carry up to four molecules of oxygen1b,2b. Oxygen uptake Blood is pumped from the right ventricle to the lungs to be oxygenated. In the alveoli, the partial pressure of oxygen is higher than that in the blood and the partial pressure of carbon dioxide in the alveoli is lower than that in the blood. The pressure differences make it possible for oxygen to diffuse from the alveoli to the blood, thus binding to the iron in the hemoglobin. Carbon dioxide on the other hand diffuses from the blood to the lungs. Carrying oxygen, blood is returned to the left atria then to the left ventricle which pumps it to the rest of the body2c. Oxygen release: In the tissues and organs, the cells are undergoing metabolism, continually consuming oxygen and releasing carbon dioxide. This means that the intracellular partial pressure of oxygen is lower than that in the blood and the intracellular partial pressure of carbon dioxide is higher than that in the blood. Again the pressure differences make it possible for oxygen to diffuse from the blood to the cells and carbon dioxide from the cells to the blood, binding again with the iron in the hemoglobin. Therefore, as blood flows around the body, it continually distributes oxygen2c,6. BLOOD SUPPLY TO THE HEART Coronary flow In order to perform its functions, the heart an abundant supply of oxygen and nutrients and therefore needs a dedicated supply of blood. Coronary circulation is that part of the systemic circulation that provides blood supply to the heart. Just as the aorta leaves the left ventricle, it gives of the right and left coronary arteries9. The left coronary artery divides into smaller braches supplying blood to the apex and the posterior side of the heart, the ventricles and part of the anterior interventricular septum, the left atrium and posterior wall of the left ventricle. The right coronary artery supplies the lateral aspect of the right atrium and ventricle, the posterior wall of both ventricles and the SA node9,10. Effect of reduced coronary flow on cardiac function The energy demand of the cardiac muscle is so crucial that an interruption of blood supply to any part of the myocardium can cause necrosis within minutes9. A decrease in coronary flow to levels below normal is called myocardial ischemia. The ischemia can be caused by vascular spasms of the coronary arteries, atherosclerosis or increased activity of the heart beyond levels that the coronary arteries can supply10. Temporary or reversible obstruction of coronary blood flow can cause chest pain known as angina pectoris9. Chronic myocardial ischemia can lead to myocardial infarction where myocardial cells die and are replaced by scar tissue. Reduced coronary flow therefore can affect cardiac function in several ways. If the heart is not able to meet its metabolic demand, it can be understood that it will not be able to pump enough blood to the body. Reduced blood flow to the rest of the body can result in serious physiological and pathological conditions which are beyond the scope of this essay. With the death of some cardiac cells as in the case of chronic ischemia, several other life threatening conditions can arise which affect cardiac function. One of such dangerous conditions is ventricular fibrillation which is an abnormal pulse generation triggered by the damaged myocardial cells. The heart will not be able to pump blood but will just quiver around without any net output. Death can occur within minutes2b,6. Treatment of reduced coronary flow Other immediate effects like ventricular fibrillation caused by reduced coronary flow can be treated by defibrillation. However, the main cause of reduced coronary flow is coronary artery occlusion or restriction and the following treatment options are available: Coronary bypass: This is a surgical technique where the occluded coronary artery is cut and replaced by a new blood vessel, usually a vein taken from somewhere in the patients body2b. Coronary balloon angiography (cardiac catheterization): This is another surgical procedure where a catheter containing a balloon at its tip is passed into the occluded artery. The balloon is enlarged thus stretching the artery and opening it in the process2b. The use vasodilator drugs such as nitroglycerine: These drugs dilate the coronary artery thereby lowering the total peripheral resistance. This reduces the work the heart must do in ejecting blood. This is usually given to people who have already suffered myocardial infarction to reduce the risk of another occurance2b,10. A person at risk of myocardial infarction can be put a low cholesterol, low fat diet to reduce the risk of atherosclerosis and takes aspirin to reduce the risk of blood clot formation. Conclusion The cardiovascular system is one of the most important systems of the body. All the other systems and organs of the body depend on it for supply of oxygen and nutrients and removal of metabolic wastes. The heart acts as a pump to make sure blood is circulated to all parts of the body through pulmonary and systemic circulations9. However, the heart itself needs supply of blood in order to perform its main function of pumping blood and the heart is supplied by the coronary circulation. Reduction in coronary flow means the heart will not be able to meet it metabolic needs and therefore cannot pump enough blood. This can adversely affect normal activity of the body and cause death10. References Sherwood L. Fundamentals of physiology a human perspective. St. Paul Minn: West publishing company; 1991.190-199 1b. Sherwood L. Fundamentals of physiology a human perspective. St. Paul Minn: West publishing company; 1991.263-266 Vander A, Sherman J, Luciano D. Human physiology, the mechanisms of body function, seventh edition. Boston: McGrow-Hill; 1998. 387-389. 2b. Vander A, Sherman J, Luciano D. Human physiology, the mechanisms of body function, seventh edition. Boston: McGrow-Hill; 1998. 374-377. 2c. Vander A, Sherman J, Luciano D. Human physiology, the mechanisms of body function, seventh edition. Boston: McGrow-Hill; 1998. 479-483. Koeppen M B, Stanton A B. Berne and Levy physiology, sixth edition. Philadelphia, PA: Mosby/Elsevier; 2008. 289-303 Serguei Semenov (2009): Lecture notes. Physiological measurements, ecg/pacemakers/defibrillators. Cohen J B, Wood L D. Structure and function of the human body, seventh edition. Philadelphia: Lippincott Williams and Wilkins; 2000. 195-204. Vandegriff K.D, Benazzi L, Ripamonti M, Perrella M, Tellier Le Y.C, Zegna A, Winslow R M. Determination of the rate and equilibrium constants for oxygen and carbon monoxide binding to R-state human Hemoglobin,199: The journal of Biological Chemistry ; 266 (26): 17049-17059 Elaine N M, Katja H. Human anatomy and physiology, seventh edition. Menlo Park: Benjamin Cummings; 2007.674-681 Sherwood L. Human physiology: from cells to systems, sixth edition. Belmont, CA: homson/Brooks/Cole; 2007.300-304 Saladin K S. Anatomy and physiology: The unity of form and function, fifth edition. Maidenhead: McGraw-Hill Higher Education; 2009.683-755 Stanfield C L, Germann W J, Niles J N, Cannon J G. Principles of human physiology, third edition. San Francisco: Pearson/Benjamin Cummings; 2009. 361-366 Skeletal Muscle Question: Describe the structure of skeletal muscle and how it contracts (90) and discuss a disease that may arise from this system (10) The structure of skeletal muscle and the mechanism of muscle contraction including muscle disease (1553 Words) 1.0 ABSTRACT Skeletal Muscle is a form of fibrous tissue with the fibers arranged parallel to each other. A muscle fiber (cell) is surrounded by the endomysium. A group of these cells is wrapped by fascicles. Bundles of fascicles are covered by the perimysium and bundles of the perimysium are wrapped by the epimysium to form a muscle. The muscle fibers have contractile properties which enable them to move bony levers in order to produce skeletal movement1. The functional unit of the muscle fiber is the sacomere which consists of most importantly, actin and myosin. The actin and myosin are arranged such that during contraction, they can slide over each other thus shortening the muscle2. Muscles suffer from many diseases, one of which is polymyositis. This is an inflammatory myopathy that affects mainly the muscles of the thorax and those around the torso. It affects all age groups but has been noticed mainly in late childhood and early adulthood. The sypmtomps are nonspecific but results in general muscle weakness and the cause, though believed to be an invasion by the white blood cells, is not very clear10. 2.0 The Structure of Skeletal Muscle. In daily life, structures and arrangements of designs are dictated, to a large extent by the purpose and function for which the design is meant for. Knowing that skeletal muscle is made up mainly of fibrous tissues, the arrangement of these tissues and how they are bound together to maintain a particular shape in order to accomplish different purposes (mainly to generate force and produce movement) may to a large extent, define the structure of the muscle4. At a macro level, the skeletal muscle is composed of bundles of individual muscle fibers, the supporting structure called the basal lamina, and the connective tissue sheaths as shown in figure 1. These connective tissues bind the cells together giving them strength and partly providing mechanical protection2. We can examine these connective tissues and their functions as follows: 2.1 The basal lamina. This is an extracellular matrix that acts as a scaffold on which a cell sits. It has been realized that apart from providing structural support, the basal lamina can orient and constrain cell during the process of regeneartion3. 2.2 The endomysium. This is a fine sheath of connective tissue that surrounds each individual muscle cell. The endomysium consist of loosely interlacing fibers composed mainly of collagen4. 2.3 The perimysium and fascilces. The individual muscle fibers wrapped by the endomysium, are grouped together in what is called fascicles. A layer of fibrous tissue called the perimysium wraps each fascicle4. 2.4 The epimysium. This is the outside layer that finally wraps the whole muscle. It is composed of dense irregular connective tissue4. Figure 1 Source: http://www.web-books.com/eLibrary/Medicine/Physiology/Muscular/muscle_structure.jpg 3.0 The muscle cell Having described how individual muscle cells are organized into a muscle, it is imperative that we look at the structural composition of the cell itself. Just like many other cells in the body are specialized according to their functions, skeletal muscle cells are specialized to produce force and movement5. The skeletal muscle fiber is thus composed of mainly three structural elements:-the myofibrils, the sarcoplasmic reticulum and the mitochondria, each contributing a unique aspect of muscle function. The entire function of the muscle can be attributed to the shifts in proportions of these three structures6. 3.1 The Myofibrills. These are cylindrical specialized sub-units within the muscle fiber. They consist of two types of contractile protein filaments-the thin filaments referred to as actin and the thick filaments referred to as myosin. The two most important parameters of the myofibrils are their diameter which determines its strength and the fiber length which determines it contraction velocity and distance over which the fiber can contract. The myofibril consist of two filaments-actin and myosin6,2. 3.1.1 Actin (thin filament). Actin filaments are responsible for regulation of contraction. The actin filament is formed by a helical arranged of actin monomers which is an ambiguous protein2 (figure 2). Because of the helical nature, a long grove is formed along the filament and the protein troponin is located at intervals along the length of the actin filament. It is troponin which is responsible for turning on contraction2,7. Figure 2.The actin molecule. Source: http://www.ucl.ac.uk/~sjjgsca/Muscleslidingfilament1.gif 3.1.2 The Myosin (thick filament). Myosin filament is about 150nm long. It has a tail and two heads. The tail is formed by two helical shaped fibers that coil around each other. A collection of several of these helical tails together form a myosin filament (figure 3)4b. Figure 3. The myosin molecule. Source: http://webanatomy.net/anatomy/myosin.jpg. 3.2 The sarcoplasmic reticulum (SR). Groups of about 200 thick and thin filaments constitute a myofibril. Each myofibril is thus enclosed in a membrane called the sarcoplasmic reticulum8. The SR membrane stores and releases calcium during muscle contraction and relaxation. The SR can therefore be thought of as the functional unit of the myofibril9. 3.3 The mitochondria. Found within the cell cytoplasm, the mitochondria are responsible for generation of most of the cells energy by the production of adenosine triphosphate (ATP). There are several mitochondria distributed along the length of a myofibril4. 4.0 The mechanism of muscle contraction Muscle contraction can largely be attributed to the structure of actin and myosin, their arrangement within the SR and the interaction between them in order to produce force (Figure 4). This type of arrangement allows the thin actin filaments to slide in and out by the action pull of the myosin heads8b. Figure 4. Actin and myosin arrangement: Source: http://www.exrx.net/Images/ActinMyosin.gif Muscles are composed of a number of actin and myosin filaments arranged in series in a basic unit called the sacomere. The sacomere consists of a thick filament in the meddle and two thin filaments, one overlapping on each side. The heads of the thick filament attach to the thin filament at the overlap and these heads allow movement in only one direction. When activated, each thick filament head rachets repeatedly along the actin, pulling the two actins closer together. Since the actin are attached to the Z line (The distance between two Z lines form the sacomere), ends of the sacomere (Z lines) are pulled in and the sacomere shortens. The sacomeres are arranged in series so that when the muscle fiber contracts, all the sacomeres contract simultaneously transmitting the force to the end of the muscle. The whole process of contraction described above occurs when the muscle is electrically stimulated2b. 5.0 Muscle stimulation. Skeletal muscle cells are stimulated by the motor neurons of the somatic nervous system. The reception of the motor stimulus (action potential) opens the calcium channels allowing calcium which is stored in the SR to be released. The release of calcium causes the release of acetylcholine-Ach (neurotransmitter). The calcium binds to the troponin on the actin filament. Troponin then regulates the tropomyosin which obstructs binding sites for myosin. This allows the tropomyosin to move, unblocking the bonding site. Myosin then binds to the unblocked site on the actin and applies a pull. This will pull the Z bands towards each other thus shortening the sacomere, causing muscle contraction2b. However, as calcium is released, the ATP-dependent calcium pump is activated and it continuously pumps calcium back to the SR to be stored again. This leads to a drop in calcium level within the cytoplasm. When the calcium level is too low, the calcium binding action to troponin is terminated, releasing tropomyosin which again blocks the binding site. This stops the interaction between actin and myosin thus relaxing the muscle2b. 6.0 Muscle Diseases There are a number of muscular diseases and disorders ranging from acquired, familial to congenital. Limiting ourselves to one of the acquired disorders of the muscles, lets look at polymyositis. 6.1 Polymyositis (PM). PM is a type of muscle inflammatory myopathy. Just like the name suggests, this disease causes inflammation of the muscle fiber. Although the causes of the disease are not well understood, it is believed that PM begins when white blood cells, spontaneously invade muscles. This can result in severe muscle weakness. Polymyositis is a persistent disease characterized by periods of increased and reduced or no symptoms. PM affects mainly the muscles of the thorax and is more common in women than men. It is said to affect all age groups although is it commonly noted in early childhood or 20s10. Key pathologic and diagnostic features of the disease. Endomysial inflammation. This is the inflammation of the outer connective tissue that surrounds the muscle fiber. This is done by the white blood cells that leave the blood and enter the tissue, somehow confirming the earlier assertion that the PM begins when white blood cells invade muscles. Invasion of myofibers by autoaggressive lymphocytes. This is when the T lymphocytes begin to attack the intact myofibers. Unlike in muscle dystrophy where inflammation is associated with degenerating myofibers, the invasion of T lymphocytes causes inflammation of health myofibers in PM.This causes inflammation of healthy myofibers. Other diagnostic features that may not be exactly specific to PM include myofiber necrosis, myophagocytosis, myofiber atrophy and fibrosis, a feature of chronic PM10,11. 7.0 Conclusion Human movement is only possible because of the action of muscle contraction. Voluntary contraction of muscle is made possible by the somatic nervous system which sends out an action potential activating the contraction process. The process is accomplished by the sliding of myosin and actin over each other. Many diseases and disorders affect muscles, prominent among them is muscular polymyosis which causes inflammation of the muscles mainly around the torso. Its believed to be caused by the unwanted action of the white blood cells and the symptoms include muscle weakness.

Dickinsons Pictorials of Death Essay -- Literary Analysis

Dickinson’s Pictorials of Death Death is often thought of as a morbid or mysterious subject. Authors and poets spend their lives exploring the questions of what happens when a person dies and what lies beyond death. From the billowy heavens in the Bible to Dante’s many rings of Inferno, no one else has quite the same view as Emily Dickinson on this subject. Through her elliptical poems Dickinson paints various views of death that reveal her multifaceted outlook. She uses different methods to gain insight into the nature of death by processing through the physical aspects of death in â€Å"I hear a fly buzz—when I died†, personifying death in â€Å"Because I could not stop for death†, and reconciling death and immortality in â€Å"Behind me dips—Eternity†. All of these poems create a better understanding of Emily Dickinson’s views of death. During Dickinson’s life, death was something that happened quite often and was never far from her thought. Her house was beside the local cemetery, and, with the Civil War raging, the graveyard always seemed to have a fresh plot. This is where she spent almost her entire life. Emily was born on December 10, 1830 in the â€Å"sleepy village† of Amherst, Massachusetts that was dominated by â€Å"church and college† (Dickinson, Emily). Here she spent her childhood years playing with her brother Austin and sister Lavinia and would later spend her adult years gardening and writing in solitude (Dickinson, Emily). Her isolation gave the impression of being reclusive and antisocial. Emily Dickinson did, however, go off to school and graduated from Amherst Academy in 1947 before coming back to her childhood home and becoming â€Å"a more than ordinary observer of Amherst life† (Dickinson, Emily). Her voluntary seclusion was not b... ...y in the image of â€Å"the Setting Sun† (BOOK PG#). Works Cited Anderson, Charles R. "The Trap of Time in Emily Dickinson's Poetry." ELH 26.3 (1959): 402-24. JSTOR. Web. 28 Mar. 2012. Anderson, John Q. "Heaven Beguiles the Tired: Death in the Poetry of Emily Dickinson." Rev. of Book. The South Central Bulletin 27.1 (1967): 30-31. JSTOR. Web. 27 Mar. 2012. Chuan, Xiao -. "Death and Immortality: The Everlasting Themes." Canadian Social Science 5.5 (2009): 96-99. CSCanada. Canadian Academy of Oriental and Occidental Culture, 2 July 2009. Web. 27 Mar. 2011. â€Å"Dickinson, Emily (1830-1886).† Encyclopedia of World Biography. Detroit: Gale, 1998. Gale Biography In Context. Web. 27. Mar. 2012. Spencer, Mark. "Dickinson's Becase I Could Not Stop for Death." The Explicator 65.2 (2007): 95-96. Taylor and Francis Online. Atypon Literatum, 7 Aug. 2010. Web. 27 Mar. 2012.

Definition Essay - Genre -- Definition Essay

Definition Essay – Genre "Genre," in the most generic definition, takes the meaning "kind; sort; style" (OED). Prior to the term's inception, the notion of genre in the study of media emerged in The Poetics, with Aristotle's discussion of the mode or manner of imitation in poetry. Of this Aristotle writes, "the medium being the same, and the objects [of imitation] the same, the poet may imitate by narration - in which case he can either take another personality as Homer does, or speak in his own person, unchanged - or he may present all his characters as living and moving before us" (Aristotle, 53). Here lies the distinction between epic, lyric, and drama, a distinction based solely in convention, the usage of the medium, independent of specific content (see also Narrative/Lyric/Drama). Yet Aristotle's genre binary of Tragedy and Comedy rests on some observation of the objects of imitation themselves: "Comedy aims at representing men as worse, Tragedy as better than in actual life" (Aristotle, 52). Later, in Section IV of The Poetics , Aristotle offers another method of generating this binary, based in historical observation (or some semblance of it). One final consideration, that of a work's purpose, arises in Aristotle's definition of Tragedy as "through pity and fear effecting the proper purgation of these emotions," (Aristotle, 61). In this way The Poetics sketches out the basic framework of genre; yet this framework remains loose, since Aristotle establishes genre in terms of both convention and historical observation, and defines genre in terms of both convention and purpose. In Anatomy of Criticism (1957) Northrop Frye wrote, "We discover that the critical theory of genre is stuck precisely where Aristotle left ... ...ohns Hopkins University Press, 1979. Frye, Northrop. Anatomy of Criticism. Princeton University Press: Princeton. 1990. Lacey, Nick. Narrative and Genre: Key Concepts in Media Studies. New York: St. Martin's Press, 2000. Liddell & Scott. An Intermediate Greek-English Lexicon (Middle Liddell). London: Oxford University Press, 1968. MacLuhan, Marhsall. Understanding Media. Malmkjà ¦r, Kirsten. "Genre Analysis." The Linguistics Encyclopedia. Ed. Kirsten Malmkjà ¦r. New York: Routledge, 1991. Monaco, James. How to Read a Film. Oxford University Press: New York. 1981. Trowse, Nadeane. "The Exclusionary Potential of Genre: Margery Kempe's Transgressive Search for a Deniable Pulpit." The Rhetoric and Ideology of Genre. Cresskill, NJ: Hampston Press Inc., 2002. Warshow, Robert. The Immediate Experience. Harvard University Press: Cambridge. 2001.

Search for the American Dream in Arthur Millers Death of a Salesman :: Death of a Salesman

Search for the American Dream in Arthur Miller's Death of a Salesman What is the American Dream? Some believe in the nineteen fifties ideal created through television. Successful children, perfect families, and a happy stay-at-home mother are all associated with this version. Yet, everyone knows that the children are not always successful, there are family fights, and not every mother can be at home and happy. Many families have lifelong searches for the ideal American Dreams and never find one. These types of families are seen as failures. One family in this type of search is represented in Death of a Salesman through Willy, Linda, and their sons. Willy Loman is the first character to represent the search of the American Dream. First, Willy has a strong belief of the American Dream because of his brother Ben. "Why boys, when I was seventeen I walked into the jungle, and when I was twenty-one I walked out. And by God I was rich." This quote by Ben is the bases of Willy’s beliefs for his family and himself. By this understanding, Willy thinks he will never need to search for anything; it would come to him. Next, Willy instills this same belief within his sons. "Listen to this. This is your Uncle Ben, a great man! Tell my boys, Ben!" When Willy states this to Ben he wants his boys to have the same thought on life as himself. Though, like their father, the two sons are led to the idea that greatness will come to them. Finally, Willy does not ever understand his search until the end of the play. "What-what’s the secret?" Willy asks Bernard this question which shows he is still searching for the key to the American Dre am. At the end of the play, Willy believes that the only answer to the success of his family is through his death. Linda Loman is the next character to represent her search for the American Dream. At first, Linda’s search is for good family relationships. After the big plans are made for the sporting goods shop, Linda’s spirits seem very high. Everyone in her family is getting along, therefore she is happy. These little perks of happiness are enough to keep her dream alive. Then, Linda has a more true view on her family’s search. Comments like, "Your such a boy," and, "One a philandering bum," are insights on what Linda sees within her sons.

Donna Tartt’s The Secret History Essay

Nietzsche’s philosophy has made for itself a unique cornerstone in the sense that it is not involved with pedantic aspects of ethics and other branches of epistemology. This seminal German thinker moves swiftly along majority of philosophical schools of thought. His exploration of the classical elements in literature, as found in the ancient Hellenic society, is manifested beautifully in Birth of Tragedy. The longstanding debate between the subjectivity and the objectivity of art is addressed to critically by Nietzsche in this book. The basic idea he propagates in Birth of Tragedy involves reality with forms and the same without, and the comparison therein. Known as the Dionysian and the Apollonian, this classical Greek model sums up humankind’s perpetual struggle to arrive at a state of equilibrium. Nietzsche argues that in our effort to pursue a meaningful existence, we need to discard the preposterous viewpoints of the Apollonian and have to embrace the Dionysian. Similar thoughts are expressed in Hermann Hesse’s illustrious work Steppenwolf which thematically deals with the Nietzschean Apollonian versus the Dionysian. The protagonist Haller is psychologically preoccupied with two contrasting facets of personality – the sensible and logical faculty of mind as opposed to the passionate and appetitive. Nietzsche assigns the terms ‘Apollonian’ and ‘Dionysian’ to these two primal worldviews of Greek tragedy. This essay is going to make a comparative study between the Apollonian and the Dionysian with reference to modern literature. To make the comparison, we have chosen Donna Tartt’s The Secret History, one of the originative post-modern fictions from the fatalistic school of literary works. In many ways, this novel echoes the Athenian concept of fate as being an overpowering element responsible for altering the desirable course of events. Idiosyncrasy is the key conceptual component in Nietzsche’s ethical doctrines. Time and again, he questions the acceptability of the prevalent trends that outline the social norms and fashions. What is far less understood in a generic attempt manifests itself intelligibly when associated with a context. â€Å"Nietzsche does not present us with a systematic theory of knowledge. Any attempt to construct one on the basis of his scattered remarks, aphorisms, poetry, and myth would be a difficult, if not impossible, task. It would, above all, be contrary to the intention of his thought and lead to a distortion of his views. Nietzsche, as Walter Kaufmann rightly asserts, is not a system builder, but a problem thinker. † (Pfeffer, p. 95-96) Now in the context of the ancient Greek anthology, both the Apollonian and the Dionysian worldviews were present, resulting in a clash of ideologies. Nietzsche borrows these two terms from the two Greek gods Apollo and Dionysus. The former symbolically represents clarity of form and interpretation, and therefore is suggestive of a linear human personality. Dionysus, on the other hand, stands for frolic and extravagance, hinting at the presence of multiple personalities within a single entity. On one hand he is the god of chaos and unrestrained emotions. But at the same time, he is also the divine countenance of richness and productivity. Hence the Dionysian school of thought deals with formlessness of expression which is closer to art perceived from an unbiased and liberal standpoint. Greek tragedy in its heydays attained sublimity when the two distinctive art forms merged with one another to form a seamless continuum. The beginning of Athenian tragedy was hinged on the Dionysian tradition before the other one sprang up, neutralizing the discordant elements. In a way, fluidity of the Dionysian elements seek platitude through the Apollonian directness. It was a matter of great curiosity for Nietzsche that such contrasting ideologies should ever be able to define tragedy (Pfeffer, p. 32). The flowing nature of Greek opera is worth mentioning in the context of the Dionysian. Music to a great extent is governed by the freedom of form and expression. Normative aspects of the Apollonian do not comply with the ecstatic jubilance conveyed through music. It evokes directly to man’s impulsive and spontaneous nature and hence, is not limited to the external forces of reason and dependence. The ingrained harmony in music is therefore counterbalanced by the Apollonian concept of plastic arts and epic poetry. What makes Greek tragedy a culmination of the Apollonian and the Dionysian is that the poetic genre characterized by reasoning can actually strike a harmonious chord and reach a level of elevated intensity as well as greater profundity. So the expansive verticality of this blending highlights Nietzsche’s exemplary vision of thought and his engineering capacity to induct precision qualities into the philosophy of literature. His unique interpretation of art and tragedy is not based on the conventional techniques. Rather it dissociates itself from the content and creates an aura of universality which can be aptly applied to any epoch of literary practices: â€Å"After recognizing this immense antithesis, I felt a deep need to explore the nature of Greek tragedy which is the profoundest manifestation of the Hellenic genius; only now did I seem to possess the key to probe deeply into the essential problems of tragedy that were no longer derived from conventional aesthetics. † (Pfeffer, p. 32) What is stated in the previous part of discussion is affirmed furthermore by Ansell-Pearson in A companion to Nietzsche. In Birth of Tragedy, he develops a style which is not only mechanical in discourse, but also highly sporadic in terms of articulating the individualistic notions so distinctive of Nietzsche (Ansell-Pearson, p. 58). The metaphysical utterance of Nietzsche deviates from what the contemporary philosophers such as Schopenhauer propagated in their doctrines. Many Greek authors, Euripides for instance, viewed the cosmos as a continuous process of creation primarily in accordance with the Apollonian traits. The Dionysian break down of form is not associated with the fictional content of human existence. The antithetical elements inherent in any human being are overlooked by Euripides in Bacchae. Claims made by Kant and Goethe that form and matter are irreversible in nature are given a refreshing new direction by Nietzsche in Birth of Tragedy. He establishes a linkage between what Euripides calls ‘organic fiction’ and plurality of human nature. He does not try to draw any kind of imposed distinction between the two incongruous constructs. Euripides’ Bacchae does not fit into Nietzsche’s delineation of metaphysics. If we strive to look into Bacchae in the light of the Apollonian and the Dionysian derivatives, we would be able to see clearly into the dubiousness of the latter one. Chronicling the historical event of Dionysus’ arrival to the royal court of Greece, Euripides presents a controversial topic involving man’s stance in relation with god. Even though this drama is written to question many of the old systems of belief, what remains extremely perplexing is the playwright’s ultimate focus. Euripides questions the vague borderline between intellect and feeling, reality and vision, and logic and craziness. But at the same time, he refrains from arriving at any conclusive outcome that would give a clue to the reason behind mankind’s endless misery. What Donna Tartt portrays in The Secret History resembles the thematic literary genealogy of Bacchae. The idea which is propagated through this novel involves the secularism of spirit as the ultimate winner in modern world. The sheer fatality of occurrences at random does not leave a chance of revisiting the past to find plausible explanations. In this sense, this novel is comparable with Birth of Tragedy and its promotion of the Dionysian worldview. This novel can be seen as a modernistic attempt to recreate the primitive world of the Dionysian rites and rituals. On the surface it is just a murder mystery which does not deserve any deeper analysis. But Tartt invests in this apparent murder mystery a profound understanding of the Apollonian versus the Dionysian, and the confrontation between reality and imagination, between social impositions and the human longing for liberation. Aristotle’s viewpoint on the Catharsis is also dealt with effectively, creating an opening for interpreting life outside the beauty of literary premises. A deeper understanding of The Secret History is bound to reveal the classical and literary elements explored in the novel. The etymology of this representative work is closely analogous to both Nietzsche’s Birth of Tragedy and Euripides’ Bacchae. It is indeed fascinating to find a connective bonding with two earlier works dissimilar in nature. First and foremost, Nietzsche’s confrontation with disillusionment in the context of Athenian literature dominated by the Apollonian worldview is stripped off in The Secret History. Events occurring within a timeline which is non-linear in nature do not imply Schopenhauer’s doctrine of the world as ‘maya’ (Segal, p. 361). The gradual disorientation of the lives of six students predates Nietzsche’s preoccupation with answering the question involving human individualism and its manifold expressions. The Secret History propels the earlier school of thought introduced by Schopenhauer: â€Å"Although Nietzsche frequently speaks of â€Å"illusion† in connection with Dionysus and tragedy, he has in mind Schopenhauer’s notions of the world as â€Å"maya†, the self-deception with which human beings (with the exception of the Nietzschean philosopher) mask the emptiness and meaninglessness of their lives, and hardly the kind of theatrical, and metatheatrical, illusion of my chapter on metatragedy. † (Segal, p. 361) It is clear from the three readings that The Secret History along with Steppenwolf is ideologically in proximity to Nietzsche’s Birth of Tragedy. What emerges out of Euripides’ Bacchae is a different doctrinal claim which does not provide any scholarly ground for either the Apollonian or the Dionysian worldviews. Euripides leaves it ambiguous as to which school of thought should the literary definition of tragedy comply with. It is rather a mixture of the Dionysian revelry associated with choir singing and the Apollonian poetry. However, the drama does not provide too much room for calculating the extent of each, therefore making the task of classification immensely difficult and problematic. References Pfeffer, R. (1972). Nietzsche: disciple of Dionysus. Lewisburg: University of Bucknell. Segal, C. (1997). Dionysiac poetics and Euripides’ Bacchae. Princeton: Princeton University Press. Ansell-Pearson, K. (2006). A compilation to Nietzsche. Hoboken: Wiley-Blackwell.

Life of Pi †Significance of Color Essay

A woman once said, â€Å"There is no life without color. † This is just the case with the main character of â€Å"The Life of Pi†, Pi Patel. Pi is a cast away on a lifeboat in the middle of the Pacific Ocean with a tiger, an orangutan, a hyena and a zebra. There is one color that was mentioned multiple times throughout the story, the color orange. In the novel â€Å"Life of Pi† by Yann Martel, this color is used as a symbol for hope and survival. To hope means to wish for something with expectations of its fulfillment. Pi’s case is a pristine example of hoping for something. He has many instances when he gains hope throughout the novel, including building a raft, landing on the island, or even finding the food in the locker of the lifeboat. The most important, is the hope Pi is given through his companion on the lifeboat, Richard Parker, a four hundred and fifty pound Royal Bengal tiger. Being the color orange, the tiger becomes an example of hope throughout the book. Pi realizes, to keep himself, Richard Parker, and the will to survive alive, he must tame the tiger. â€Å"I had to tame him. It was at that moment that I realized this necessity. It was not a question of him or me, but of him and me. We were, literally and figuratively, in the same boat. We would live–or we would die–together. † (Martel, 164) Keeping Richard Parker alive would allow Pi to constantly remember that he is not the only one suffering and he has someone there for him, whether he can answer or not. Although Pi has many reasons to be hopeful, the author gives the reader reasons as well. Prior to the scene of the sinking of the Tsimtsum, an interviewer and reporter that is talking to Pi about the sinking of the ship describes visiting Pi later in life at his home in Canada. He meets Pi’s family and mentions that Pi’s daughter, Usha, holds an orange cat. â€Å"Leaning against the sofa in the living room, looking up at me bashfully, is a little brown girl, pretty in pink, very much at home. She’s holding an orange cat in her arms. † (92) This scene guarantees the reader that the end result of the story and Pi’s life will be not total tragedy. Pi has a life where he has been successful and has children of his own. While in the middle of the Pacific Ocean, Pi’s only goal was to survive. Items on the boat and religion truly gave him this will to survive, and Pi was more capable of surviving with them in his presence. While on the lifeboat, Pi has an orange life jacket with an orange whistle, an orange buoy, a bright orange tarpaulin, and a four hundred and fifty pound Bengal Tiger. Pi is thrown on the lifeboat by Chinese men with a life jacket already on him. â€Å"One of the men interrupted me by thrusting a life jacket into my arms and shouting something in Chinese. I noticed an orange whistle dangling from the life jacket. (105) The life jacket is used by Pi in constructing a raft to have a safe place away from Richard Parker, and the whistle is used by taming the large tiger. He utilizes his bright orange survival equipment to stay alive and keep away from Richard Parker. For most of the voyage they take on the lifeboat, Richard Parker remains under the tarpaulin, even from the beginning. After Pi is pushed overboard into the lifeboat, he says â€Å"I couldnâ⠂¬â„¢t see Richard Parker. He wasn’t on the tarpaulin or on a bench. He was at the bottom of the boat. † (106) Richard Parker having orange fur, is a symbol of survival. He keeps Pi alert and continuously reminds him of his situation. Religion played a big part of Pi’s life, and he prayed three times a day every day while he was on the boat. His family’s religion is Hinduism, and orange is the color of the second Hindu chakra, which are believed to be centers of the body from which a person can collect energy in the religion. Throughout his entire journey, he was always in contact with something that was the color orange, and that is why it becomes a symbol of survival. Every item and detail of his trip aids him in survival, and is part of the outcome of him being rescued. The color orange will always be remembered by Pi and readers as the color of hope and survival. The color gives readers hope for Pi and gives Pi the will to survive because of the possessions that are that color. The items Pi has on the boat all aid in his miraculous survival, just as Richard Parker and the religions he practices provides a measure of emotional support. These help the young boy maintain hope in this horrific tragedy. But above all, the orange color of survival and hope will always be known as the color that kept him alive.