BSC 2346 Module 4 Case Study

BSC 2346 Module 4 Case Study • Question 1 1 out of 1 points Jordan is now 19-years old. As an infant, Jordan reached many gross motor skill milestones, such as holding his head up, rolling over, sitting, and standing, at normal times. However, he was considered a “late walker” because he took his first steps at 17 months. By 2 years old, his parents noticed a hyperlordotic posture while he was standing. A Gower's sign and Trendelenberg gait were noted by age four. Throughout his childhood, he suffered progressive muscle weakness, especially in the proximal musculature of the arms, pelvis, and legs. He required orthotic braces to assist his walking and was confined to wheelchair ambulation by age 13. At 16, he was hospitalized with bronchitis requiring antibiotic treatment, but recovered. Jordan has a history of progressive muscle weakness, but no history of muscle pain or spasm, chest pain, or irregular heartbeat. The only medications that he normally takes are calcium and fluoride supplements. Jordan has three siblings. His older and younger sisters have never had any major medical issues. Jordan’s older brother is also to a wheelchair with problems similar to Jordan's. No other immediate or distant family members have musculoskeletal issues. Jordan’s history aligns most closely with which diagnosis? Selected Answer: Duchenne muscular dystrophy Answers: Multiple sclerosis Myotonic dystrophy Amyotrophic lateral sclerosis • Question 2 Duchenne muscular dystrophy 0.5 out of 1 points Jordan had a biopsy of the left gastrocnemius muscle when he was 5 years old. Based on your answer for his diagnosis, describe the microscopic pathological changes that the pathologist would have noted in her report. Selected Answer: Correct Answer: the muscle would show degeneration in comparison to earlier biopsy Degenerating skeletal muscle fibers. Proliferation of connective tissue around the degenerating muscle cells. Numerous macrophages in the area. Muscle fibers that appear more dense or dark in color. Response Feedback: • Question 3 [None Given] 1 out of 1 points Explain, in your own words, why Jordan’s brother appears to have the same disease and why his sisters are unaffected. Selected Answer: Correct DMD or Duchenne muscular dystrophy is inherited and typically boys affected as girls are typically just carriers. Answer: Duchenne muscular dystrophy (DMD) is a progressive form of muscular dystrophy that occurs primarily in males. Genetic changes causing Duchenne muscular dystrophy (DMD) can be passed down in families. The DMD gene is located on the X chromosome, one of the two types of sex chromosomes. Males have an X and a Y chromosome; whereas females have two X chromosomes. Response Feedback : [None Given] • Question 4 1 out of 1 points Jordan’s calves appear enlarged. Which of the following statements explains this phenomenon? Selected Answer: Answers: As his muscles degenerate, the muscle tissue is replaced by collagen and adipose tissue. As Jordan ages, the neuromuscular junction loses its neurotransmitters. Jordan’s muscle cells are experiencing calcification because the actin and myosin filaments are no longer able to release from each other. As his muscle degenerate, calcium replaces the water in the muscle cells. As his muscles degenerate, the muscle tissue is replaced by collagen and adipose tissue. • Question 5 1 out of 1 points Jordan displayed Gower’s sign at a young age. Which of the following statements explains why this this true? Selected Answer: The weakness of his proximal leg muscles and erector spinae muscles force Jordan to use his arms to push on the floor. Answers: His neuromuscular junctions were interrupting the signals to contract his muscles. The chronic contractures in Jordan’s lower legs cause him to be reliant on his upper body for strength. Jordan’s quadriceps and gluteus maximus are in spasm, which causes him to fall to his knees when trying to stand. The weakness of his proximal leg muscles and erector spinae muscles force Jordan to use his arms to push on the floor. • Question 6 0 out of 1 points Weakness in his erector spinae muscles forces Jordan to assume which exaggerated position when standing? Selected Answer: Scoliosis Answers: Lumbar hyperlordosis Cervical hyperlordosis • Question 7 Scoliosis Thoracic hyperkyphosis 1 out of 1 points In your own words, please explain why Jordan must take calcium supplements for the rest of his life. (Hint: Think about your prior material and Wolff’s law.) Selected Answer: He will take calcium supplements because if he doesn't bear weight on his legs, his legs will think they don't need to build and maintain the strength and bone density Correct Answer: Calcium provides material to build bone extracellular matrix Response Feedback: [None Given] • Question 8 1 out of 1 points Jordan is prone to respiratory infections, in part because of the weakness of which muscles? Selected Answer: Diaphragm and abdominal wall muscles Answers: Serratus anterior and scalene muscles Pectoralis major and pectoralis minor Diaphragm and abdominal wall muscles • Question 9 Hyoid muscles 1 out of 1 points Genetic testing would reveal that Jordan has a y-linked disorder. Selected Answer: Fals e Answers: True Fals e • Question 10 1 out of 1 points In your own words, briefly describe the role of dystrophin within the motor unit. Selected Answer: Correct Dystropin is a protein that helps build muscle cells- strengthen muscle fibers, and protect from injury when muscles contract and relax. Answer: Mechanical: 1. stabilization of membrane (sarcolemma) during contraction & relaxation 2. link between intracellular cytoskeleton & extracellular matrix Functional: 1. differentiation of muscle fibers 2. organization of postsynaptic membrane and ACh receptors Response Feedback: [None Given] • Question 11 1 out of 1 points Colette has been experiencing some muscle pain and soreness after workouts this last week. She decides to research how muscles work because she wants to find ways to help alleviate her pain. She is hoping to find out the names of the muscles that are aching and find ways to stretch and strengthen them. Answer the following questions to help her find the answers she is looking for. Colette has been sore “all over,” but her primary area of concern is the posterior right thigh. Which of the following muscles could be causing the soreness in this region? Selected Answer: Biceps femoris Answers: Biceps femoris Vastus lateralis Rectus femoris • Question 12 Peroneus longus 1 out of 1 points Colette has played softball for over 20 years and has been told in the past that she may have a rotator cuff injury. Which of the following rotator cuff muscles is on the anterior aspect of the scapula? Selected Answer: Subscapula ris Answers: Infraspinatu s Subscapula ris Supraspinat us • Question 13 Teres minor 1 out of 1 points Colette is trying to understand what causes her occasional calf muscle cramps. Which of the following statements is true regarding cramps? Selected Answer: Answers: Cramps are thought to be caused by hyperexcitiability of the motor neuron. Cramps are caused by a sedentary lifestyle. Cramps are voluntary, continuous contractions of sarcomeres. Cramps are caused by excess calcium and ATP. Cramps are thought to be caused by hyperexcitiability of the motor neuron. • Question 14 0 out of 1 points According to the sliding filament theory, myosin filaments slide past actin filaments during contraction of a muscle because the myosin heads bind to the sarcolemma. Selected Answer: True Answers: True Fals e • Question 15 Which of the following statements is true regarding muscle contraction? 1 out of 1 points Selected Answer: When a muscle contracts, the H-zone becomes narrower Answers: (shortens). When a muscle contracts, the H-zone becomes narrower (shortens). When a muscle contracts, the A-band shortens. When a muscle contracts, the lighter I-band becomes wider. • Question 16 When a muscle contracts, the sarcomere remains the same size. 1 out of 1 points Colette is having trouble understanding the role of fascia within the musculoskeletal system. Explain, in your own words, how fascia is related to the muscles of the human body. Selected Answer: Correct Fascia is found around all the muscles, groups of muscles, and bones. It surrounds everything in the body and helps the muscles move without much friction. It connects everything. If the fascia is tight, it can be just as painful as a tight muscle Answer: An individual skeletal muscle may be made up of hundreds, or even thousands, of muscle fibers bundled together and wrapped in a connective tissue sheath called the epimysium, which gives the muscle its shape, as well as providing a surface against which the surrounding muscles can move. Fascia, connective tissue outside the epimysium, surrounds and separates the muscles. Response Feedback: [None Given] • Question 17 1 out of 1 points Colette is finding that studies about the benefits of stretching have mixed results. However, stretching can improve flexibility, which is a priority for her. Which of the following statements is true? Selected Answer: Stretching increases blood flow to the muscle being stretched. Answers: Stretching weakens the ability of actin and myosin binding process. Static stretching has been shown to reduce soreness and increase athletic performance. Stretching increases blood flow to the muscle being stretched. Stretching increases the risk of injury in adolescent and elderly patients. • Question 18 1 out of 1 points In your own words, describe how acetylcholine, calcium, and ATP are involved in the process of muscle contraction. Selected Answer: Correct these are the 3 things needed for a muscle to contract. ACh is basically the electrical impulse. ACh, calcium and ATP "bind" together causing the contraction (power stroke). ACh causes electic impulse to move in both directions of the muscle fiber. The actin is exposed as calcium binds to tropin. ATP attaches to the myosin head causing it to detach. Answer: Acetylcholine is released from axon bulbs, binds to muscle cells and then the muscle gets excited. Calcium is released from sarcoplasmic reticulum and binds to troponin that is around actin. ATP breaks the myosin-actin cross-bridge, freeing the myosin for the next contraction. Response Feedback: [None Given] • Question 19 1 out of 1 points While Colette is researching weight lifting techniques, she finds contradictory information about the “best” way to build muscle. Which of the following statements is true of skeletal muscle? Selected Answer: Fast glycolytic fibers are used for actions like weightlifting, fatigue very quickly, and have very little myoglobin content. Answers: The speed of muscle contraction is not dependent on how fast the myosin heads split ATP. Fast glycolytic fibers are used for actions like weightlifting, fatigue very quickly, and have very little myoglobin content. Anaerobic exercise depends on oxygen. Slow oxidative fibers have a low myoglobin content and are used for explosive muscle movements, like sprinting. • Question 20 1 out of 1 points Muscle relaxation occurs when acetylcholine is cleaved from its receptors, calcium is pulled back inot the sarcoplasmic reticulum, the myosin is released from its binding site, and the muscle fiber returns to its resting length. Selected Answer: True Answers: True Fals e