STAT101

• What are skeletal muscles and skeleton often considered together as?

  A functional unit that permits body movements and locomotion
• How are muscles attached to bones?

  By connective tissue called tendon
• What is the broad, flat, sheet-like tendon called?

  Aponeurosis
• What are the two points of attachment for skeletal muscles?

  One fixed (origin) and one movable (insertion)
• What is the fixed point of attachment of a muscle called?

  Anatomical origin
• What is the movable point of attachment of a muscle called?

  Insertion
• What is referred to as the belly of the muscle?

  The part between the origin and insertion of a muscle
• What are muscles with more than one origin called?

  Heads
• What are muscles with several insertions termed?

  Slips
• How can locating the anatomical origin and insertion of a muscle help?

  It can facilitate identification of a muscle
• What factors can help identify a muscle?

  Shape, relative size, direction of muscle fibers, and action
• What are the bases for naming muscles?

  • Attachment (origin and insertion)
  • Anatomical location
  • Shape
  • Size and action
  • Direction of muscle fibers
• What is an example of a muscle named based on its attachment?

  Sternoradialis (sternum as origin, radius as insertion)
• What is an example of a muscle named based on its anatomical location?

  Pectoralis muscles (located at the chest region)
• What is an example of a muscle named based on its shape?

  Deltoid (triangular in shape)
• What is an example of a muscle named based on its size?

  Adductor magnus (large)
• What is an example of a muscle named based on the direction of its fibers?

  External oblique
• What are the common terminologies used to describe muscle actions?

  • Adductor: moves a part towards the main axis
  • Abductor: moves a part away from the main axis
  • Extensor: moves jointed parts away from each other
  • Flexor: moves jointed parts towards each other
  • Levator: raises a part
  • Depressor: lowers a part
• What is the objective of the dissection activity involving the skeletal muscles of the toad?

  To identify major muscle groups and relate their actions
• What materials are needed for the dissection of a toad or frog?

  Preserved toad/frog, dissecting pan, dissecting set
• What is the first step in skinning the specimen during dissection?

  Rinse off excess formalin with tap water
• Why should the pointed ends of the scissors be directed upward while making the midventral slit?

  To avoid injuring the underlying muscles
• What should be done after making a midventral slit on the skin of the specimen?

  Make a transverse cut around the body just above the hindlimbs
• What should be noticed between the skin and muscles during dissection?

  The large spaces are the subcutaneous lymph sacs
• What is important to remember when separating muscle bundles during dissection?

  Observe the direction of the fibers and the extent of the muscle
• What should never be used to separate muscle bundles?

  Sharp instruments like scissors or scalpel
• What should be done if it is necessary to cut superficial muscles to find deep muscles?

  Cut through the belly of the muscle
• What should be done to identify the muscles during dissection?

  • Locate and identify muscles based on descriptions
  • Confirm identification by finding anatomical origin and insertion
  • Note anatomical differences between frog and toad
• What is the first muscle to locate in the ventral muscles of the head and trunk?

  Submentalis
• What is the origin of the submentalis muscle?

  Anterior tip of the mandible
• What is the insertion of the submentalis muscle?

  Anterior angle of the lower jaw
• What action does the submentalis muscle perform?

  Raises the tip of the lower jaw
• What is the origin of the mylohyoid muscle?

  Median surface of the mandible
• What is the insertion of the mylohyoid muscle?

  Median raphe
• What action does the mylohyoid muscle perform?

  Raises the floor of the mouth during breathing or swallowing
• What is the origin of the geniohyoid muscle?

  Anterior angle of the lower jaw
• What is the insertion of the geniohyoid muscle?

  Posterior cornua and thyroid processes of the hyoid
• What action does the geniohyoid muscle perform?

  Draws the hyoid forward and upward
• What is the origin of the sternoradialis muscle?

  Episternum and omosternum
• What is the insertion of the sternoradialis muscle?

  Radius