muscular system

• how many muscles are in the body?


  600
• types of muscles:

  • visceral
  • cardiac
  • skeletal
• what is visceral muscle?


  smooth muscle tissue that is included in organ muscle.
• where is cardiac muscle found?


  only in the walls of the heart.
• what is the skeletal muscle?


  a type of muscle that:

  • forms mechanical systems making the body to be able to move limbs and other parts of the body.
  • is connected to the skeleton.
  • is voluntary
  • contains striated, tubular and multi nucleated fibres.
• what does smooth muscle do?


  contains fibres that are:

  • striated
  • spindle shaped
  • un- nucleated
• what does smooth muscle cover?


  walls of internal organs
• what is cardiac muscle?


  a muscle that's:

  • involuntary
  • only contained in the walls of the heart.
  • contains striated, branched and un nucleated fibres.
• what is a muscle?


  a band of fibrous tissue that contracts and relaxes to aid movement.
• what are sarcomers?


  the basic unit of contractive units ofd striated muscle.
• what are sarcomeres composed of?


  proteins causing microfilaments to slide past each other when a muscle relaxes or contracts.
• what are microfilaments?


  think myosin and thin actin filaments.
• what do sarcomeres each contain?


  a central bundle of myosin that is overlapped at both ends by actinfilaments.
• what is each myosin filament?

  surrounded by 6 actin filaments
• what is myosin filaments made up of?


  myosin molecules.
• what do myosin molecules have?


  a flexible head to bind to the actin.
• what do sarcomeres break down?


  ATP
• what is muscular contraction?


  it is an action potential from a motor neuron which triggers the release of acetylcholine into motor end plate.
• what does acetylcholine initiate?


  depolarisation within muscular fibre.
• what does depolarisation cause?


  sarcoplasmic reticulum to release stores of calcium ions.