1. actin
    thin filaments that consist of twisted chain of actin molecules
  2. myosin
    • thick filament are bundles of many myosin molecules
    • each molecule consists of two long polypeptide chains coiled together, each ending in a large globular head
    • the heads have sites that bind to actin, forming bridges between the actin and myosin
    • heads also contain ATPse activity
  3. sarcomeres
    functional unit of a myofibrils, bounded by the Z lines
  4. titin
    • protein that binds the bundles of myosin filaments together
    • titin molecules are very elastic, accounting for the resistance to stretch in relaxed skeletal muscle
  5. tropomyosin/troponin
    • tropomyosin blocks the place where the globular head would beind
    • troponin holds tropomyosin in place and can be activated (move tropomyosin) in the pressence of Ca++
  6. Rigor complex
    when in the absence of ATP, actin-myosin bonds can't be broken
  7. motor unit
    muscles fibers connected to a single motor neuron
  8. Transverse tubules (T-tubules)
    plasma membrane that allows nerve synapses to activate the entire muscle fiber simultaneously
  9. twtich
    smallest unit of contractoin, measured in tension
  10. tetanus
    the maximum amount of tension generated by a muscle fiber
  11. What are the mechanisms that control the strength of a muscle contraction
    • Increase the APF in each motor neuron
    • Recruitment of motor units
  12. Slow-twtich fibers (red muscle)
    • have many mitochondria
    • lots of myoglobin
    • prolonged aerobic ATP production
    • well supplied with blood vessels and fuel reserves
  13. Fast-twitch (white muscle)
    • develop maximum tension more rapidly
    • fatigue rapidly
    • myosin have high ATPase activity but cannot replenish ATP fast enough
  14. immediate system
    • pre-formed ATP and creatine phosphate is used as energy supply muscles with energy
    • only lasts a couple of seconds
  15. glycolytic system
    • metabolizes carbohydrates to lactate and pyruvate producing ATP
    • anaerobic - can only be done for about one minute before lactic acid build up slows the reaction
  16. oxidative system
    • metabolixes of carbohydrates or fats to water and CO2 producing ATP through the electron transprot system and ATP synthase in mitochondria
    • can be done for extended periods of times but takes about a minute to start functioning and is only limitted by blood flow
Card Set
bio final