APK Exam3 Ch12 PI

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  1. 4 Mechanisms of Force Generation in Muscle
    • Sliding filament theory
    • Crossbridge cycling
    • Neuromuscular junction
    • Excitation-contraction coupling
  2. Plasma mem of a muscle cell
  3. Cytoplasm of a muscle cell
  4. Endoplasmic reticulum of a muscle cell
    Sarcoplasmic reticulum
  5. 4 major components of muscle fiber
    • Multinucleated
    • Many mitochondria (provides en for contraction)
    • Transverse tubules (T tubules)
    • Many myofibrils
  6. Part of a muscle fiber that is a deep invagination of the sarcolemma and is physiologically important for excitation-contraction coupling
    Transverse tubules (T tubules)
  7. Long, thin strand which gives skeletal and cardiac muscle a striated (striped) appearance and which are orderly arranged as sliding thick (myosin) and thin (actin) filaments
  8. Thin filament
  9. Thick filament
  10. A segment of myofibril which is the contractile unit and is the smallest functional unit of a muscle
  11. Part of sarcomere which is a thick filament that forms dark bands
    A band
  12. Part of sarcomere which is a thick filament and has no overlap
    H zone
  13. Part of sarcomere which links thick filaments
    M line
  14. Part of sarcomere which links thin filaments
    Z linePart of sarcomere which is a thick filament that forms a light band and consists of no overlapping
  15. ___ is a "filament" or a polymer of G actin, and each G actin has a binding site for myosin
    F actin
  16. Each ___ of a F actn has a binding site for myosin
    G actin
  17. Regulatory protein which covers myosin binding sites on actin so that myosin cannot bind to G-actin, inhibiting muscle contraction. It's position is controlled by troponin
  18. Tropomyosin together with troponin, regulate the binding of _____ to ____
    myosin to actin
  19. A protein complex which is associated with a tropomyosin and consists of 3 polypeptide subunits which each binds to actin, tropomyosin, or calcium
  20. When troponin binds to Ca, it causes _____, which in turn draws tropomyosin away from its blocking position
    conformational change
  21. Myosin head binding sites: (2)
    • Actin binding site
    • ATP binding site (ATPase)
  22. Myosin tail is toward ___ and myosin head is toward ____
    • M line
    • I band
  23. Very elastic protein which supports protein in muscle by anchoring thick filaments b/w M line and Z line
  24. During muscle contraction, thick (myosin) and thin (actin) filaments slide over each other instead of shortening
    Sliding-Filament Mechanism
  25. Sequence of events whereby an action potential in the sarcolemma causes contraction
    Excitation-Contraction Coupling
  26. Excitation-contraction coupling requires calcium to be released from ___ and is dependent upon neural input from ___
    • sarcoplasmic reticulum
    • motor neuron
  27. Synpase b/w motor neuron and skeletal muscle
    Neuromuscular junction
  28. Receptors on skeletal muscle cells are called ___ and respond to ___ which is released from the motor neuron
    • nicotinic cholinergic receptors
    • acetylcholine
  29. During excitation-contraction coupling:
    1.) action potential starts in _____,
    2.) travels down ______,
    3.) then ____ receptors of T tubules open Ca channels (___ receptors) in lateral sacs of SR
    4.) Ca increases in cytosol & binds to troponin shifting tropomyosin,
    5.) and crossbridge cycling occurs
    • sarcolemma
    • T tubules
    • DHP receptors
    • ryanodine receptors
  30. First source of ATP which is used up very rapidly and can provide 4-5 times the amt of ATP present in cell at rest
    Creatine phosphate
  31. Creatine rxn
    Creatine phsophate + ADP <--creatine kinase--> Creatine + ATP
  32. Primary energy source during light to mod exercise (aerobic) b/c there is enough oxygen avail
    Oxidative Phosphorylation
  33. How does body maintain adequate oxygen?
    1.) Increase ventilation
    2.) Increase HR and contraction
    3.) ___
    Dilate vessels to muscle
  34. During oxidative phosphorylation, where does energy come from during beginning vs later exercise?
    • Glucose in muscles (as glycogen) for first 30 min, thereafter,
    • Glucose (in small amts) & FAs delivered to muscle by blood
  35. Primary source of ATP energy when oxygen supply to muscle is limited:
    Anaerobic glycolysis
  36. How many ATP are made per glucose during anaerobic glycolysis?
    2 (inefficient)
  37. As a result of anaerobic glycolysis and a limit to glucose availability, what happens in muscles?
    Build up lactate
  38. After exercise, respiration is still increased b/c ox phosphorylation continues. Sometimes called ____. At this time, ___ and ___ are replenished, and ___ is converted back to ____.
    • oxygen debt
    • creatine phosphate & glycogen stores
    • lactate to pyruvate
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APK Exam3 Ch12 PI
APK Exam3 Ch12
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