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GMS 6474 final exam/196 Questions and Solutions Distinction Scores
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GMS 6474 final exam/196 Questions and Solutions Distinction Scores
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GMS 6474 final exam/196 Questionsand Solutions Distinction Scores
what does the SR store - -proteins and calcium -what is the role of the transverse tubules in the muscle fiber - -allow inside of muscle to communicate with the outside of the muscle -how is a sarcomere measured - -from z-disc to z-disc -what is contained in the I band of the sarcomere & what color is the band - -thin filaments titin z-disc
light (isotropic) -what is contained in the A band of the sarcomere & what color is the band -
-thick filaments thin filaments dark (scatters light) -what is contained in the H zone & what color is the band - -thick filaments light no barbs or myosin middle zone of the sarcomere -what is contained in the M line - -in the middle of the sarcomere, middle of H zone thick filaments myomesin -what does titin do in the sarcomere - -structural protein -how many zones can you see when the sarcomere is relaxed - -all zones can be seen in relaxed state -how many zones can be seen when the sarcomere is contracted - -
sarcomere shortens I band shortens H zone disappears thick and thin filaments overlap DONT shorten -what is the contractile unit of skeletal muscle - -the sarcomere -what is the main component of the thick filaments - -myosin
have heavy and light chains motor heads that move it along the thin filament -what is the largest protein in the body - -titin -what are the main components of the thin filaments - -actin (where myosin
binds)
troponin (moves tropomyosin when Ca2+ is present)
tropomyosin (covers actin active site)
nebulin (sets thin filament length) CapZ (anchors actin to Z-line on z-disc side)
Tropomodulin (on end of actin, in middle of sarcomere)
alpha-actinin (anchors actin to z-line) -what does desmin do in the sarcomere - -interacts with alpha-actinin to anchor z-disc to sarcolemma -what does dystrophin do in the sarcomere - -connects sarcomere to sarcolemma stabilizes the sarcolemma to prevent damage during contractions -1st step of cross-bridge cycle - -BINDING activated myosin binds to actin ADP and Pi are still bound to myosin -2nd step of cross bridge cycle - -POWER STROKE myosin head swivels
movement of actin filament
ADP and Pi released from myosin
(Pi is released first, before ADP is released) -3rd step of cross bridge cycle - -DISSOSCIATION
ATP binds to myosin Actin and myosin dissociate (cross bridge detaches) -4th step of cross bridge cycle - -ACTIVATION
ATP hydrolysis energy activates myosin head ADP and Pi remain bound to myosin if Ca2+ still present, cycle continues -how does Ca2+ effect the cross bridge cycle - -Ca2+ is needed for the troponin to move the tropomyosin off the actin
when Ca2+ runs out, the cross bridge cycle will stop troponin has 4 Ca2+ binding sites -how does Ca2+ get into the cell to trigger the cross bridge cycle - -through
the RyR channels, which are activated by the DHPR channel mechanical change IN SKELETAL MUSCLES -what are the two roles of ATP in the cross bridge cycle - -release from rigor state re-energize/reactivate myosin heads for next cycle -what resequesters Ca2+ to end muscle contraction - -SERCA -where is the sarcoplasmic reticulum located - -wrapped around the sarcomeres and throughout the myofibrils -what is the role of the sarcoplasmic reticulum in muscle cells - -stores Ca2+ that is needed for contraction -what are the components of the triad in the muscle cell - -sarcoplasmic reticulum t-tubule -what is the role of the triad in the muscle cell - -communication center -what are the two main receptors in the triad - -dihydropyridine receptors (DHPR)
ryanodine receptors (RyR) -what is the role of the DHPR in the triad - -voltage sensor
sense when action potential is moving down t-tubule -what is the role of the RyR in the triad - -Ca2+ release channel -what kind of pennate muscle fiber formation has the most force production - -multipennate -what muscle fiber arrangement is best for speed - -when they are stacked on top of each other (like a building) -what muscle fiber arrangement is best for strength - -when they are next to each other (like a trailer) have more tension -what kind of muscle contraction action has the most tension - -isometric contraction -how many endplates do muscle fibers have - -one endplate per muscle fiber
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