LABORATORY FIVE

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LABORATORY FIVE

• The Skeletal Muscle System Anatomy

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Organization Terminology

• Epimysium Around entire muscle (bundles of
  fascicles)
• Perimysium Around fascicles (bundles of muscle
  fibers)
• Endomysium Around each muscle cell (fiber)
• P81, Fig. 5.1 This is a whole muscle
• P82, P83, p84, Fig. 5.6, 5.7, 5.8 These are
  each one muscle cell (fiber) Notice the
  peripheral nuclei
• P82, Fig. 5.2 Microscopic view of a skeletal
  muscle
• Sarcomere contractile subunits
• Z lines separate sarcomeres
• A (Dark) bands - length of myosin
• I (Light) bands - actin only

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Motor Unit Neuromuscular Junction

• Motor Unit (P82, Fig. 5.3) motor neuron muscle
  fibers it innervates (stimulates)
• Neuromuscular junction (P83, Fig. 5.6) the point
  of communication between a motor nerve and a
  skeletal muscle fiber
• Motor end plate the contact surface on sarcolemma

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Skeletal muscles Contraction
In order for contraction of a muscle to cause
movement, there are attachment sites on two
different bones Origin Less movable
attachment Insertion More movable
attachment Action Moves insertion toward origin
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Muscle Action and Origin/Insertion

• You need to learn the action of muscles listed on
  the provided handout use flash cards or
  highlight them in your lab manual
• For muscles with more than one listed action,
  learn the action that pertains to the joint
  within parenthesis
• Origin insertion are extra credit learning
  material. Learn all muscles Origin and Insertion,
  not just the muscles listed on the provided sheet
• Both origin/insertion and action questions will
  be just a written question not on the model

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Identification of Human Skeletal Muscles

• Mostly superficial muscles and only a few deep
  muscles
• ID some attachments by name (indicated with an
  in the tables)
• ID muscles that work the head, neck, shoulder,
  anterior posterior trunk, elbow, wrist, hip,
  knee, and ankle
• View superficial muscles on leg and arm models
  (do not take them apart)
• Flexors anterior view
• Extensors posterior view
• View deep muscles on the torso model and on the
  head, neck, and shoulder model
• Right side superficial muscles
• Left side deep muscles

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Head Neck

• P85, Table 5.1 Epicranius consists of frontalis,
  occipitalis, galea aponeurotica
• Scalenes Remove the sternocleidomastoideus
• Posterior trunk
• Splenius Erector Spinae Remove Trapezius
  Latissimus dorsi

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Trunk
Transversus abdominis can only be viewed
internally
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Quadriceps Group
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Hamstring Group
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Actions of Human Skeletal Muscles (Extra Credit)

• When a skeletal muscle contracts, the insertion
  moves toward the origin producing an action (a
  movement)
• The resulting action depends on the anatomy of
  the joint and the type of movement it can
  generate
• Flexion/Extension A movement that
  decreases/increases the angle between two bone
• Abduction/Adduction Movement of an appendage
  away from/toward the midline
• Rotation Movement of a bone around an axis
• Circumduction Movement of an appendage in a
  circle around a joint
• Pronation/Supination Turning the palm
  posterior/anterior
• Inversion/Eversion Turning the sole of the foot
  toward/away from the midline
• Dorsiflexion/Plantarflexion Moving the ankle
  joint to stand on your heel/point your toe
• P104, Table 5.2 draw a stick figure in
  anatomical position circle the appropriate
  joint in the 1st column. In column 2 3 you can
  just draw the joint using arrows pointing in
  opposite directions to indicate the movement

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Prioritize studying for Lab 5

• Name of muscles most questions
• ALL of the muscles included in the lab manual are
  assigned for identification purposes
• Gross and microscopic view of skeletal muscle
• Assigned muscle actions (provided handout)
• e.g. Name the muscle that extends elbow triceps
  brachii
• Origin insertion of all muscles in the lab
  manual (extra credit)

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Grades for First Practicum

• Answer key is posted on the window
• Grades A, B, C Congratulations!
• Continue doing what youre doing
• Help your classmates get better
• Tell them your learning strategy
• Make sure you get a grade C or better on the
  lecture portion of the course
• Grade D in lab, and C or better in lecture
• Read ahead, get yourself familiarized with the
  upcoming lab
• Visit the last hour of other labs with
  instructors permission
• Attend open lab regularly
• Make sure you turn in all your completed lab
  reports on time
• Do all the extra credit assignments
• Make sure you do well on the lecture portion of
  the course
• Grade F
• This should be a wake up call for you
• What you have been doing is not working for you
• Change your learning strategy
• Talk to your classmates who have been successful
  on the first practicum
• Form study groups