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30 Cards in this Set
- Front
- Back
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The embyrological origin of muscle
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Mesoderm.
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4 functions of muscle tissue
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Movement, stablilization, storage and substance distribution (blood and lymph are moved via contraction), thermogenesis
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What's the only motor neuron type we're concerned with in skeletal movement?
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Alpha.
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3 things that stimulate a muscle
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Hormones, ions, pH
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Characterize epi and perimysium
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dense irregular type I
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As a side note, what determines the relationship between range of motion and strength?
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Inversely proportional. The arrangement of the fasicles.
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Where are the nucleii in skeletal muscle fibers?
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Peripheral.
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Flow chart of muscle embryo
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Myoblasts fuse -> syncytial myotube -> myofibrils
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I band
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Thin filaments. The dots in cross section are tiny (pg. 741)
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Z line (simply)
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Attachment for thin filaments
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A band
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Overlap of thick and thin filaments. Dots are big and little (pg. 741)
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H band
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Thick filaments mostly only (big thick dots regularly spaced in cross section pg. 741)
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M line (in cross section)
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Looks like a hexagon divided into triangles. What I doodle when I'm on the phone. Cross-bridges
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What protein makes the thick filament?
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Myosin (type II)
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What protein makes the thin filament?
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Actin
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What protein holds the thin and thick filaments together? What protein binds THAT protein to itself and the Z disk?
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Desmin. Plectin
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How long is the sarcomere?
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2.25 microns.
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What are the terminal cisternae and where are they located?
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A pair of SR extensions at the jxn of A and I bands
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What is the function of the terminal cisternae?
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Sequestering calcium.
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How much of what is released from the terminal cisternae on contraction?
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Ca. ALL OF IT. (In skeletal muscle)
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The most abundant protein in the membrane of SR?
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The Ca pump, Ca-ATPase
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Where is calquestrin?
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The lumenal side of the SR
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How does the Ca get from the SR to the T tubule?
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Bridging proteins that probably connect to the Ca-release channel
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How many T tubules are associated with each sarcomere?
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2. Therefore 2 complete triads
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Two proteins associated with the Z disk and their functions
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a-actinin, bind to the thin filaments with nebulin
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Purpose of tropomyosin
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Strengthen the thin filaments
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The three components of troponin and their purposes
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1. TnT: binds all 3 to tropomyosin
2. TnC: Calcium binding site 3. TnI: Actin binding, prevents myosin and actin from interacting |
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Purpose of dystrophin (non-TL)
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Binds thin filaments to sarcolemma membrane proteins, and therefore unites contraction with external tissue (laminin)
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What happens when there is no dystrophin? Major clinical evidence?
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The sarcolemma cannot keep Ca out, and the muscle tissue dies. Hypertrophy occurs as dead tissue accumulates and fat invades. Think of the big calves on DMD patients
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Where on myosin is the actin-binding site?
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Heavy chain.
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