Muscles

Card Set Information

Author:
jaguavai
ID:
105824
Filename:
Muscles
Updated:
2011-10-02 18:07:35
Tags:
Pharm 410
Folders:

Description:
Muscle contraction and relaxation
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user jaguavai on FreezingBlue Flashcards. What would you like to do?


  1. Thick muscle filament structure
    Made up of several hundred myosin protein molecules
  2. Muscle deactivation step 1
    Ca2+ levels decrease
  3. Muscle deactivation step 2
    Troponin reverts to its original confirmation
  4. Muscle deactivation step 3
    Tropomyosin reverts, covering the myosin binding sites on the actin thin filament
  5. Muscle deactivation step 4
    Myosin heads are no longer able to bind actin and the thick and thin filaments slide back to their original positions (muscle relaxes)
  6. Thin filament structures (3)
    • Actin
    • Tropomysin
    • Troponin
  7. Sliding filament mechanism of contraction step 1
    Cleavage of ATP do ADP and Pi causes the myosin hinge to open, extending the head to a position further along the F-actin filament. High energy confirmation
  8. Sliding filament mechanism of contraction step 2
    Myosin heads in the high-energy confirmation attach to a binding site on F-actin
  9. Sliding filament mechanism of contraction step 3
    • Pi is released from myosin, causing the hinge to close. This is called a power stroke and causes the thick and thin filaments to slide past one another
    • ADP is also released during the power stroke
  10. Sliding filament mechanism of contraction step 4
    Actin-bound myosin heads bind ATP, which releases the heads from the actin.
  11. Tropomysin structure
    A coiled, a-helical, fibrous protein that threads alont the F-actin fibers. It normally blocks the myosin binding sites on actin, unless shifted by troponin
  12. Troponin scructure
    A trimeric, globular complex that binds the tropomysin strands at regular intervals. Troponin binds Ca2+, this binding stimulates a conformation change that results in troponin moving tropomysin away from the myosin binding sites on actin.
  13. Muscle contraction activation step 1
    Muscle fiber Ca2+ concentrations increase as a resulf ot a nerve signal
  14. Muscle contraction activation step 2
    Troponin binds the Ca2+ and undergoes a conformational change
  15. Muscle contraction activation step 3
    The troponin conformational change induces a shift in the position of the tropomysin strand, exposing muyosin binding sites on the surface of the actin filament.
  16. Myosin structure (4)
    • Protein containing two intertwining a-helical tails and two globular heads
    • head contains a site that allows myosin to bind to the thin filament protein actin
    • Protein hinges on the head allow it to extend out and rock back and forth
    • Head also contains an ATP binding site
  17. Actin structure (3)
    • Globular protein that polymerizes to form fibers (F-actin).
    • Two F-actin fibers coil around each other to make the thin filament core.
    • Contains binding sites for myosin on the thick filament.
  18. Thick muscle filament structure (1)
    Made up of several hundred myosin protein molecules.
  19. Thin filament structures (3)
    • Actin
    • Tropomysin
    • Troponin

What would you like to do?

Home > Flashcards > Print Preview