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Ch 8 Muscular System
Question | Answer |
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Characteristics of skeletal muscle | -Attached to bones and moves parts of the skeleton -Striated, alternating dark and light bands -Voluntary control -Limited capacity for regeneration |
Characteristics of cardiac muscle | -Found only in the heart -Striated -Involuntary, contractions are not under conscious control |
Characteristics of Smooth muscle | -Located in the walls of hollow internal structures, such as blood vessels, airways, the stomach, and intestines. -Participates in internal processes such as digestion and the regulation of blood pressure -Nonstriated -Involuntary -Regenerates |
Five functions of muscular tissue | 1. Producing body movements 2. Stabilizing body positions 3. Regulating organ volume 4. Moving substances within the body 5. Producing heat |
Describe the function of fascia | -bandage- applied to a sheet or broad band of fibrous connective tissue beneath the skin or around muscles and other organs of the body. -Holds muscles together and separates them into functional groups. |
Describe the composition and function of a tendon | -A cord of dense regular connective tissue composed of parallel bundles of collagen fibers. -Attaches muscle to bone |
Describe the function of sacrolemma and T-tubules | -Each muscle fiber is covered by a plasma membrane called the sarcolemma -Transverse Tubules (T-tubules) are tunnel like extensions of the sarcolemma, they pass through the muscle fiber from side to side. |
Describe the composition and function of a myofibril | -Extend along the entire length of the muscle fiber -cylindrical structures -Consists of two types of protein filaments that over lap forming sarcomeres, the basic functional unit of striated muscle. |
Describe the function of actin, tropomysin, and troponin. | -Actin, a protein in Z discs. individual actin molecules join o form an actin filament that is twisted into a helix. -Tropomyosin and troponin cover the myosin-binding sites on actin in relaxed muscle fibers. |
Describe the parts of a neuromuscular junction | Synaptic vesicles- contain ACh Synapse-space between nerve and muscle Receptor- catch the ACh |
Five events that happen at a neuromuscular junction | 1. Nerve impulse 2. vesicles release acetylcholine (ACh) 3. ACh diffuses across synaptic cleft to receptors. 4. Receptors trigger potential movement 5. Acetylcholinesterase cleans ACh off of receptors so they can again be used. |
Summarize the events that cause contraction and relaxation in skeletal muscle fiber | 1. Myosin heads split ATP and become reoriented and energized 2. Myosin heads bing to actin, forming crossbridges 3. Myosin heads rotate toward center of the sarcomere 4. As myosin heads bind ATP, the crossbridges detatch from actin. 5. repeat. |
Describe the causes of Ducheyenne and Becker Muscular Dystrophy | Recessive gene carried on the x chromosome. Females cant get it because they have another x chromosome. |
Define "cramp" and summarize their causes | sudden, brief, usually painful contraction of a muscle or group of muscles. Happends to healthy people, commonly after excersize or during rest. -Caused by inadequate blood flow to the muscles and low levels of electrolytes |
Describe the causes and symptoms of Fibromyalgia | -Causes: Unknown, can be worsened by physical or mental stress, poor sleep, repetitive strains, injury, and chronic dampness and cold. -symptoms: widespread pain and stiffness, worsens with fatigue, straining, overuse. Has trigger points thatcauseflareup |
Describe the source of pain in shin splints ans their cause | The shin muscle pulls the foot up and the calf pulls it down. While walking calf muscle exerts so much force, it can injure the shin muscle |
Describe the symptoms of a muscle strain | worse pain when moved, dull pain when relaxed |
Describe the sources of pain in tendon inflammation and causes for tendon inflammation | Source: Tendons itself or inner lining of fibrosis. Causes: over exertion, suddenly pulling, moving it, creating friction between outer surface and adjacent bone. |
Describe the symptoms of myasthenia gravis | Weak drooping eyelids, double vision, excessive fatigue, difficulty speaking and swallowing, weakness of arms and legs |