Muscular System

  1. What are the functions of the system?
    • Movment Breathing
    • Posture
    • Heat Production
  2. Define Neuromuscular Junction
    the site where motor neuron and muscle fiber meet
  3. The neuromuscular junction parts in order of impulse transmission are:

    What is the role of acetylcholinesterase?
    • 1. Axon Terminal--neurotransmitter-release acethylcholine (ACh)
    • 2.Synaptic cleft is the space
    • 3. Motor end plate(MEP)--> modified sarcolemma--contains ACh receptors
    • Acetylcholinesterase is an acethylcholine degrading enzyme.
  4. The Functional unit of the Muscular System?
    Sarcomere--> the smallest functional unit
  5. The components of Sarcomere are:
    Thin filament--is made of actin and attached to Z-disc

    Thick filament-- is made of myosin and is centeral location
  6. Define Sliding Filament Theory & what must be supplied to promote relaxation?
    Sliding Filament Theory is when the actin and mysoin bind--> thin fliament move over thick filaments and the sarcomere shortens

    Requirement for relaxation is ATP.
  7. Define Motor Unit---all-or-none law and recruitment
    • Motor Unit is motor neuron & all muscle fibers it stimulates
    • All-or-none law is when the maximum contraction of all fibers in the motor unit.
    • Recruitment is increased motor units and increased contraction force
  8. Define Twitch and Tetanus
    • Twitch is a rapid response of a muscle fiber to a threshold stimulus.
    • Tetanus is substaned contraction due to rapid stimulation and summation of twitches (prolonged contraction of skelectal muscles)
  9. What is refractory period and what is it's length ?
    Refactory period is the period which a threshold stimulus produces no response.

    length = short
  10. Endurance Exercise
    Endurance Exercise is aerobic metabolism without interruption for long periods of time. This promotes physical fitness.
  11. Physical Fitness
    Physical Fitness is the ability to do work.

    This is overwhelmingly related to changes in skelectal muscles (not heart or lungs) that allow it to use oxygen more efficiently.
  12. Major functions of skeletal muscles on outline:
    • Vertebral column
    • ---sternocleiodomastoid (flexes)
    • ---abdominals (flex): rectus adominis, external oblique, internal oblique

    • Upper Extremity at shoulder
    • ----pectoralis major (flexes)
    • ----deltoid(abducts)
    • ----latissimus dorsi(extends)

    • Lower extremity at hip & knee
    • ----sartorius (flexes at hip & knee)
    • ----quadriceps group (extend at knee)
    • -----gluteus maximus (extends at hip)
    • -----hamstrings group (extends at hip, flexes at knee)
Card Set
Muscular System