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18 Cards in this Set
- Front
- Back
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Describe Skeletal Muscles. (6) |
* Muscle that attaches to and covers the skeleton * 40% of body mass * Longest muscle cells * Huge & multinucleate * Cannot contract without nerve stimulation * Striated, Voluntary muscle |
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Describe Smooth Muscles. (6) |
* Found in hollow, visceral organs * Forces substances through internal body channels * Elongated cells * Nonstriated, Involuntary muscle * No sarcomeres * Uses Calmodulin instead of Troponin |
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Explain the physiology of Smooth Muscle Contraction. (3) |
* Calcium is pumped out using calcium ATPase active transport pumps * Calmodulin dissociates from myosin light chain kinase. * Phosphate groups are stripped from the myosin by myosin phosphatase |
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What are the four functions of Muscle? |
* Producing movement * Maintaining body posture * Stabilizing joints * Generating heat |
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What is the basic anatomy of muscle? (4) |
* CT Sheaths * Epimysium * Perimysium * Endomysium |
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Describe muscular CT sheaths. (2) |
* Used to support and hold the muscle together during contractions * Called the Fascia |
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Describe the Epimysium. (2) |
* Dense irregular CT * Surrounds the entire muscle |
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Describe the Perimysium. (2) |
* Fibrous CT * Wrapped around the bundles of fascicles within the muscle |
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Describe the Endomysium. (3) |
* Within the fascicle * Wispy sheet of fine, areolar CT * Surrounds each individual muscle fiber |
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List the Histology of muscles. (8) |
* Muscle fiber * Thick Myofilament * Thin Myofilament * Sarcolemma * Sarcoplasmic Reticulum * Sarcomere * Myofibrils * Transverse Tubules |
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Describe Muscle Fiber. (3) |
* Elongated, striated, multinucleate cell * Surrouded by the epimysium * Has a plasma membrane (sarcolemma) |
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Describe Thick Myofilaments. (5) |
* Composed of 300 myosin protein molecules * 2 heads, a tail and a hinge * Forms cross bridges * Extends the entire length of the A band * Connected in the middle of the sarcomere at the M line |
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Describe Thin Myofilaments. (3) |
* Composed of actin molecules + proteins * Has active sites * Has regulatory proteins called Tropomyosin (covers the binding sites on the actin) and Troponin (binds with calcium) that prevent myosin binding while at rest. |
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Describe the Sarcoplasm. (2) |
* Cytoplasm of the muscle cell * Contains large amounts of Glycosomes (which produce glucose during muscle cell activity) |
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Describe the Sarcomere. (3) |
* The functional unit of the muscle * Repeats from Z line to Z line * Contains an A band |
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Describe Myofibrils. (5) |
* Fibrils embedded in fibers * Run parallel to the length of the muscle cell * Contractile elements of the sarcomeres * Tube of myofilaments * 80% of cellular volume |
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Describe the Sarcoplasmic Reticulum. (5) |
* The ER of muscle cells * Stores calcium * Releases calcium on demand when the muscle fiber is stimulate to contract * Works against the concentration gradient * Uses calcium ATPase pumps to relax the muscle |
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Describe Transverse or T tubules. (3) |
* Narrow membranous channels formed from the sarcolemma that are perpendicular to the SR * Open to the extracellular fluid * Able to conduct action potentials |
