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Duchenne muscular dystrophy essay
Essays on duchenne muscular dystrophy
Essays on duchenne muscular dystrophy
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Questions:
1. James suffers from a condition called Duchenne muscular dystrophy. Explain the full meaning of this name.
DMD also known as muscular dystrophy is muscular disease that occurs on young boys around age four to six. Muscular dystrophy is genetically transmitted disease carried from parent to offspring. This disease progressively damages or disturbs skeletal and cardiac muscle functions starting on the lower limbs. Obviously by damaging the muscle, the lower limbs and other muscles affected become very weak. This is ultimately caused by the lack dystrophin, a protein the body produces.
2. At age 4, James underwent a biopsy of the right gastrocnemius muscle. The pathologist's report noted histopathologic changes suggestive of Duchenne muscular dystrophy. Describe in detail the typical microscopic changes noted in the muscle tissue of someone with Duchenne's muscular dystrophy.
James’s biopsy of his right gastrocnemius muscle would have shown a degeneration of the muscle or skeletal fibers due to the lack of dystrophyn. Another microscopic change that would be noticed is the accumulation of white blood cells. White blood cells have a very specific function which is to clear the damaged muscle fibers from the debris. Clearly, due to some of the muscle fibers being damaged other healthy fibers that have not been damaged appear denser. By having damaged muscle fibers, all the work rest upon the healthy fibers making them contract to the fullest due to the fact that the myosin and acting would have to overlap even more to make the muscle work.
3. Which muscles are most severely affected by this disease process?
The skeletal and ultimate cardiac muscle fibers are affected by DMD. The disease starts by affecting the lower port...
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...ames susceptible to repeated lower respiratory tract infections?
As said before DMD weakens the diaphragm and intercostal muscles. These muscles aid in respiration, therefore he has a difficult time expanding his lungs making him prone to infections. Also, since he cannot control his respiratory muscles it may cause him to swallow food and aspirate it into his lungs creating obstructions in his respiratory tract. There may be a lot of different pulmonary infections James is going to be prone to because of this.
13. What is the average lifespan of an individual with Duchenne muscular dystrophy, and what are some of the more common causes of death in individuals with this disease?
The average lifespan of an individual with DMD is of about 18 years old. Some of the most common causes of death are heart failure, respiratory failure or infection and airway obstruction.
The risk factors that Jessica presented with are a history that is positive for smoking, bronchitis and living in a large urban area with decreased air quality. The symptoms that suggest a pulmonary disorder include a productive cough with discolored sputum, elevated respiratory rate, use of the accessory respiratory muscles during quite breathing, exertional dyspnea, tachycardia and pedal edema. The discolored sputum is indicative of a respiratory infection. The changes in respiratory rate, use of respiratory muscles and exertional dyspnea indicate a pulmonary disorder since there is an increased amount of work required for normal breathing. Tachycardia may arise due to the lack of oxygenated blood available to the tissue stimulating an increase in heart rate. The pedal edema most probably results from decreased systemic blood flow.
Duchenne Muscular Dystrophy, also known as DMD, is the most common form of muscular dystrophy. Muscular dystrophy is a condition that is inherited, and it is when muscles slowly become more and more weak and wasted. Duchenne muscular dystrophy is a form of muscular dystrophy that is very rapid and is most commonly found in boys. In muscle, there is a protein named dystrophin. Dystrophin is encoded by the DMD gene. When boys have Duchenne muscular dystrophy, they do not produce enough dystrophin in their muscles. This causes weakness in their muscles. Parents can tell if their child has duchenne muscular dystrophy by looking for various symptoms.
This is induced by the sliding of the cardiac myofibril. Hypertrophic Cardiomyopathy, also known as HCM, is a type of heart disease that affects the Cardiac Muscles and Cardiac Muscle cells. This disease occurs if the Cardiac Muscle cells enlarge, which causes the wall of the heart’s ventricles (most often the left ventricle) to thicken. It can also cause stiffness in the ventricles, as well as mitral valve and cellular changes. On a cellular level, HCM can cause the cells to become disorganised and lost.
Every day we use our skeletal muscle to do simple task and without skeletal muscles, we will not be able to do anything. Szent-Gyorgyi (2011) muscle tissue contraction in rabbit’s muscles and discovered that ATP is a source for muscle contraction and not ADP. He proposed a mechanism to cellular respiration and was later used by Sir Hans Krebs to investigate the steps to glucose catabolism to make ATP. In this paper, I will be discussing the structure of muscle fibers and skeletal muscles, muscle contraction, biomechanics, and how glucose and fat are metabolized in the skeletal muscles.
Duchenne's muscular dystrophy, also known as psuedohypertrophic muscular dystrophy, is a typical sex-linked disorder in which the muscles degenerate throughout a person's life. It literally means "faulty nutrition of the muscles. " Muscular Dystrophy has no cure, and this particular type of muscular dystrophy affects only males. One in 3,500 baby boys are born with this disorder and while survival is rare beyond the early 30s, death is usually caused by a respiratory disease.
In addition to these defects of DM, the normal process of aging is associated with additional risks for the
Physiological Basis of disease: DMD is the commonest and most serious form of the dystrophies. The gene responsible for dystrophin which, when absent, causes DMD. Amount of dystrophin correlates with the severity of the disease (i.e., the less dystrophin present, the more severe the phenotype). Since the gene is on the X chromosome, it primarily affects males, and females who are carriers have milder symptoms ( www.nlm.nih.gov/medlineplus/ency/article/000705.htm).
Qiao T, Liu C and Ran F. (2005) The impact of gastrocnemius muscle cell changes in chronic venous insufficiency. Eur J Vasc Endovase Surg 30; 430-436.
Emery-Dreifuss muscular dystrophy is a rare form of muscular dystrophy characterized by early onset contractures of the elbows, achilles tendons and post-cervical muscles with progressive muscle wasting and weakness It is also associated with heart complications like cardiomyopathy and arrhythmia which in both cases can lead to death. Cardiomyopathy is a heart disease which affects the muscles of the heart. In cardiomyopathy is muscles get rigid, enlarged or thick. They also sometimes changed by scar tissues. On the other hand arrhythmia is a disorder with the rhythm or rate of heartbeat. The heart can beat fast, which is called tachycardia or it could be beating too slow, which is called bradycardia. Emery-Dreifuss muscular dystrophy is characterized by early onset of contractures and humeroperoneal distribution. Humeroperoneal refers to effects on the humerus and fibula. The genes known to be responsible for EDMD encode proteins associated with the nuclear envelope: the emerin and the lamins A and C.
Muscular Dystrophy is a genetic disorder in which your muscles drastically weaken over time. Muscles are replaced with “connective tissue,” which is more of a fatty tissue than a muscular one. The connective tissue is the tissue that is commonly found in scars, and that same tissue is incapable of movement. Although Muscular Dystrophy affects muscles in general, other types affect certain groups of muscles, and happen at different periods throughout a lifetime. For example one of the most common types, Duchenne Muscular Dystrophy, targets muscles in the upper thigh and pelvis. The disease is displayed throughout early childhood, usually between ages four and seven. This genetic disorder occurs only in boys. People have difficulty sitting up or standing and lose their ability to walk in their early teens. Sadly most people die by the age of twenty. A second common type, Becker’s Muscular Dystrophy affects the same muscles as Duchenne, but first appears in teenage years. Most people with Becker’s only live into their forties (Fallon 1824-1825).
It is estimated that 1 out of every 5,600-7,700 boys ages 5-24 have Duchene or Becker muscular dystrophy. (“Data & Statistics,” 2012 April 6) Muscular dystrophy is a group of genetic diseases defined by muscle fibers that are unusually susceptible to damage. There are several different types of muscular dystrophy some of which shorten the affected person’s lifespan. (“Muscular dystrophy: Types and Causes of each form,” n.d.) There is a long history of the disorder but until recently there wasn’t much knowledge of the cause. (“Muscular Dystrophy: Hope through Research,” 16 April 2014) Symptoms are obvious and can be seen as soon as a child starts walking. (“Muscular Dystrophy,” 2012 January 19) Although muscular dystrophy mostly affects boys, girls can get it too. (“Muscular Dystrophy,” 2012 January 19) There is no cure for muscular dystrophy but there are several types of therapy and most types of muscular dystrophy are still fatal. (“Muscular Dystrophy: Hope through Research,” 16 April 2014)
The contraction of a muscle is a complex process, requiring several molecules including ATP and Cl-, and certain regulatory mechanisms [1]. Myosin is motor protein that converts chemical bond energy from ATP into mechanical energy of motion [1]. Muscle contraction is also regulated by the amount of action potentials that the muscle receives [2]. A greater number of actions potentials are required to elicit more muscles fibers to contract thus increasing the contraction strength [2]. Studied indicate that the larger motor units, which were recruited at higher threshold forces, tended to have shorter contraction times than the smaller units [3]. The aims of the experiment were to reinforce the concept that many chemicals are required for skeletal muscle contraction to occur by using the rabbit muscle (Lepus curpaeums) [2]. In addition, the experiment was an opportunity to measure the strength of contraction and to observe the number of motor units that need to be recruited to maintain a constant force as the muscles begin to fatigue [2]. Hypothetically, the rabbit muscle fiber should contract most with ATP and salt solution; and the amount of motor units involved would increase with a decreasing level of force applied until fatigue stage is reached.
Hypertrophic cardiomyopathy is an inherited disease that affects the cardiac muscle of the heart, causing the walls of the heart to thicken and become stiff. [1] On a cellular level, the sarcomere increase in size. As a result, the cardiac muscles become abnormally thick, making it difficult for the cells to contract and the heart to pump. A genetic mutation causes the myocytes to form chaotic intersecting bundles. A pathognomonic abnormality called myocardial fiber disarray. [2,12] How the hypertrophy is distributed throughout the heart is varied. Though, in most cases, the left ventricle is always affected. [3] The heart muscle can thicken in four different patterns. The most common being asymmetrical septal hypertrophy without obstruction. Here the intraventricular septum becomes thick, but the mitral valve is not affected. Asymmetrical septal hypertrophy with obstruction causes the mitral valve to touch the septal wall during contraction. (Left ventricle outflow tract obstruction.) The obstruction of the mitral valve allows for blood to slowly flow from the left ventricle back into the left atrium (Mitral regurgitation). Symmetrical hypertrophy is the thickening of the entire left ven...
With motor neurone disease it attacks the nerves, in the brain and spinal cord. This means messages gradually stop reaching muscles, which leads to weakness and wasting. In the case study the
The sarcomere is found in structures called myofibrils which make up skeletal muscle fibres. Within the sarcomere there are various different proteins. One of the most significant, myosin is found in the thick filaments of the sarcomere. Although both cells contain myosin, it is important to highlight that smooth muscle cells contain a much lower percentage of myosin compared to skeletal muscle cells. Despite this, myosin filaments in smooth muscle cells bind to actin filaments in a manner similar to that in skeletal muscle cells; although there are some differences. For instance, myosin filaments in smooth muscle cells are saturated with myosin heads so that myosin can glide over bound actin filaments over longer distances, enabling smooth muscle cells to stretch further, whilst in skeleta...