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The Muscular System

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					The Muscular
  System
               Muscle Types




http://www.nsbri.org/HumanPhysSpace/
            Skeletal Muscles
• Striated
• Bundles of
  myofibrils
• Sarcomeres,
  along length of
  fibers
• Responsible for
  voluntary
  movement
Bicep and Tricep
                  Cardiac muscles
                                   • Striated
                                   • Fibers branch &
                                     interconnect via
                                     intercalated discs
                                   • Discs – relay signals
                                     from cell to cell during
                                     heartbeat
                                     (synchronize)
                                   • Forms contractile wall
                                     of heart
Cardiac muscle – Bio 162 archive
Cardiac Muscle
              Smooth muscle
• Spindle-shaped cells
• Lacks striations
• Contracts more slowly
• Remain contracted
  longer
• Controlled by
  different nerves than
  skeletal
• Involuntary body
  activities
• Found in: walls of
  digestive tract
  (churning), urinary
  bladder, arteries
  (constriction), and
  other internal organs
Cat Throat
            Human Muscle Contraction
• Step 1: Myosin heads
  attach to binding sites
  on the actin filaments
• Step 2: Myosin heads
  move to the center of
  the sarcomere, remove
  themselves, then
  reattach to actin
  filament
• This cycle occurs
  hundreds of times per
  second during muscle
  contraction
           Muscle Contraction




Courtesy of SDSU Dept. of Biology
                  Jellyfish
• Do not have much
  control over which
  direction they will
  move in
• Create a jet propulsion
  effect to push
  themselves along
• Have a bell-shaped
  section on their body,
  which they fill with
  H2O and then release
  the H2O from beneath
                                             Clam
• Have a muscular
  foot which aides in
  its movement
• Muscualr foot
  balances from the
  front to the back
  in a wavelike
  motion, helping the
  clam move
http://images.google.com/imgres?imgurl=www.assateague.com/clam-dia.gif&imgrefurl=http://www.assateague.com/nt-
bival.html&h=206&w=300&sz=16&tbnid=Df8larSJLmgJ:&tbnh=76&tbnw=110&prev=/images%3Fq%3Dclam%26hl%3Den%26lr%3D%2
6ie%3DUTF-8%26oe%3DUTF-8
                   Starfish
• Use a water-vascular
  system and their tube
  feet to move
• H2O moves in and out
  of their feet, altering
  the pressure of the
  water and releasing
  suction, which helps
  the starfish move
  along rocks
              Lancelet Branchiostoma
• Swim by lateral
  undulations of the
  body
• Undulations are
  caused by
  contractions of the
  axial musculature
• Move in a side to
  side motion that is
  similar to swimming

 http://images.google.com/imgres?imgurl=library.thinkquest.org/C006669/media/Biol/img/lancelet.gif&imgrefurl=http://library.thinkquest.org/C0
 06669/data/Biol/chord_2.html&h=425&w=400&sz=33&t
 bnid=paT0_yBZBFYJ:&tbnh=121&tbnw=114&prev=/images%3Fq%3Dlancelet%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-
 8%26sa%3DG
            Grasshopper
• Exoskeleton, hard
  segments, which
  cover the muscles
  and visceral organs
• Muscles attach to
  the inner surface
  of exoskeleton
Bony Fish
• Contains muscles in the tail and trunk
  which are made of myotomes, also known
  as muscle blocks
• Myotomes are separated by connective
  tissue called myosepta
• The fins are made up of abductor
  muscles which open the jaw and
  adductor muscles which close the jaw
• These muscles move the fins away and
  toward the body
           Birds
• Pectoral muscles
  move wings
• Pectoral muscles are
  attached to the keel
  in order for the
  wings to spread
                                                      Frogs
• Voluntary muscles are
  present which the
  frog has control over
• These muscles occur in
  combinations of
  flexors and extensors
• Flexor contracts and
  bends
• Extensor contracts
  and straightens

http://images.google.com/imgres?imgurl=www.vrealities.com/frog2.jpg&imgrefurl=http://www.vrealities.com/education.html&h=209&w=27
5&sz=11&tbnid=xxwpZzW_jtUJ:&tbnh=82&tbnw=107&prev=/images%3Fq%3Dfrog%2Bdissection%26hl%3Den%26lr%3D%26ie%3DUT
F-8%26oe%3DUTF-8
                            Sharks
• Various skeletal muscles, in
  particular branchiomeric,
  smooth and cardiac muscles
• The branchiomeric muscles
  undergo the most
  evolutionary change
• Branchiomeric muscles are
  striated, attached to bone,
  form head muscles, and neck
  muscles
• Differences would be;
  skeletal somatic muscles and
  skeletal visceral muscles
• Skeletal somatic muscles
  deal with locomotion and
  develop from the myotome of
  epimere and somatic layer of
  hypomere
• Skeletal visceral muscles
  deal with respiration and
  feeding and develop from the
  neural crest cells
                               Human
• Skeletal muscle is controlled
  by the nervous system
   – contractions are mainly
     automatic
• Cardiac Muscle contracts by
  the sliding filament method
   – Forms branching fibers
• Smooth Muscle is controlled
  by the nervous system and
  hormones
   – Involuntary muscles because
     we are unable to control
     them
                        Sites
• http://www.tiscali.co.uk/reference/encyclopaedia/hutchinso
  n/m0007436.html
• http://quantum.plsweb.com/Common/QHomeSite/samplec
  ourse/bio36_2.html
• http://ohs-
  bio.www1.50megs.com/Biology_Notes/Fish.htm#BF%20
  Nervous%20system
• http://www.emc.maricopa.edu/faculty/farabee/BIOBK/Bio
  BookMUSSKEL.html
• http://www.flmnh.ufl.edu/fish/Education/Diagrams/FishBo
  dyParts.htm

				
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posted:5/20/2013
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