Crash course: Muscular system

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Crash course Muscular system
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Muscle Groups

• Smooth muscle smooth, involuntary found in
  internal organs such as digestive tract, uterus,
  walls of blood vessels.
• Skeletal muscle striated, voluntary,
  multinucleated contract rapidly but not for long
  periods of time.
• Cardiac muscle striated, involuntary found in
  the heart has own control centers.

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Muscle Fibers
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Muscle Types
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Muscle Anatomy

• Each muscle fiber has a nerve connected to it a
  motor neuron makes contact with the fibers
  membrane (sarcolemma).
• These motor neurons carry signals from the
  central nervous system and cause muscle
  contraction.
• Actin and myosin filaments are found in the
  center of the fiber.

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Muscle Contraction

• Nerve impulse travels through the motor neuron,
  stimulating the sarcolemma.
• Calcium is released from the sarcoplasmic
  reticulum causes myosin binding sites on actin
  to become exposed.
• ATP on tip of myosin hydrolyzes energy transfer
  changes the shape of myosin and it binds to
  actin.
• Energy is then released and myosin relaxes into
  original shape, pulling the actin with it.
• New ATP binds to myosin, and process repeats
  until contraction is complete.
• Muscle relaxes when the antagonistic muscle
  contracts (flexor and extensor).
• Calcium has to be actively tranported back into
  the reticulum to reset the system.
• Rigor mortis occurs when no more ATP is available
  and calcium is not removed from the sarcomere
  muscle stays contracted.

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Muscle structure and function animation

• http//entochem.tamu.edu/MuscleStrucContractswf/in
  dex.html

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Myofibrils song(My Sharona)

• Add a little calcium, calciumTo the cytoplasm
  near the myofibrils.It will turn troponin on,
  troponin on,Causing the contraction of the
  myofibrils.
• CHORUS
• Muscles need energy, energy,Most of which is
  needed by the myofibrils.Myosin burns ATP,
  ATPFueling the contractions of the myofibrils.
• CHORUS

• Ooh my little filaments, filaments --Actin and
  myosin myofibrilsProteins that are long and
  dense, long and dense,Making up the structure of
  the myofibrils.
• CHORUSSignal from the brain rides the nerve to
  the muscle,Where the myosin inside will slide
  past the actin of theMy-my-my-y-y, woo!
  Muh-muh-muh-myofibrils.