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what is the basic fxn of skeletal muscle?
muscle fiber
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each fiber is enclosed by a layer of connective tissue called..
endomysium
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fibers are in bundles called..?
muscle fascicles
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muscle facicles are enclosed by..?
perimysium
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most skeletal muscle are attached to bones by...
tendons (dense regular connective tissue) or membraneous sheets called aponeuroses
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when an actions occurs, ________ remains stationary while the __________ will move
the origin; insertion
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a prime mover/agonist:
a muscle that directly brings about a specific action
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an antagonist:
a muslce directly opposes that action
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synergists:
"working together" by promoting or assisting in a specific action or by reducing unneccesary movements while the action is performed
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fixators:
special class of synergists that stabilize joints/muscles so prime movers can act more efficiently
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origin of frontal belly (frontalis)
epicranial aponeurosis
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insertion of frontalis:
skin of eyebrow
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action of frontalis
raises eyebrows
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origin of occipitalis
superior nuchal line on occipital bone
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insertion of occipital belly
epicranial aponeurosis
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action of occipitalis
pulls scalp posteriorly
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orbicularis oculi origin
medial aspect of bony orbit
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orbiularis oculi insertion
skin around eyelids
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orbicularis oculi action
closes eyelid
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orbiculis oris origin
maxillary bone
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orbicularis oris insertion
lips
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orbicularis oris action
protudes lips to kiss or whistle
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buccinator origin
maxillary bone
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buccinator insertion
fibers of obicularis oris
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buccinator actions
compresses cheek while whistling
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risorius origin
fasica over masseter
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risorius insertion
skin @angle of mouth
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risorius action
draws angle of mouth laterally
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zygomaticus major origin
zygomatic bone
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zygomaticus major insertion
angle of mouth
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zygomaticus major action
raises lateral corner of mouth for smiling
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zygomaticus minor origin
zygomatic bone
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zygomaticus minor insertion
upper lip
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zygomaticus minor action
raises upper lip
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masseter origin
zygomatic arch
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masseter insertion
lateral surface of mandibular ramus
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masseter action
protudes mandible
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temporalis origin
temporal bone
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temporalis insertion
coronoid process of mandible
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temporalis action
retudes mandible
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sternocleidomastoid origin
manubrium
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sternocleidomastoid instertion
mastoid process
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sternocleidomastoid action
flexion of neck
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external intercostals origin
inferior border of superior rib
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external intercostals insertion
superiour border of inferior rib
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external intercostals action
elevates the ribs during normal inspiration
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internal intercostals origin
superior border of inferior rib
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internal intercostals insertion
inferior border of superior rib
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internal intercostals action
depresses the ribs during forced expiration
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rectus abdomis origin
pubic crest
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rectus abdomis insertion
xiphiod process
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rectus abdomis action
stabilizes pelvis while walking
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external oblique origin
external surfaces of inferior 8 ribs
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external oblique insertion
pubic crest
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external oblique action
rotation & lateral flexion of trunk
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internal oblique origin
iliac crest
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internal oblique insertion
pubic crest
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internal oblique action
rotation & lateral flexion of trunk
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transverse abdominis origin
iliac crest
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transverse abdominis insertion
pubic crest
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transverse abdominis action
increases intraabdominal pressure during forced expiration
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erector spinae muscles
iliocostalis, longissimus, spinalis muscles
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iliocostalis origin
thoracolumbar fascia
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iliocostalis insertion
angles of ribs
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iliocostalis action
extension of vertebral column & head
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longissimus origin
posterior surface of sacrum
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longissimus insertion
transverse processes of thoracic & cervical vertebrae
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longissimus action
lateral flexion of vertebral column & head
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semispinalis origin
transverse process of vertebrae
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semispinalis insertion
spinous processes of more superior vertebrae
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semispinalis action
extension of vertebral column
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pectoralis major origin
sternum
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pectoralis major insertion
lateral lip of intertubercular groove on humerus
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pectoralis major action
flexion, medial rotation & adduction of the arm
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pectoralis minor origin
external surfaces of ribs 3-5
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pectoralis minor insertion
coracoid process of scapula
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pectoralis minor action
depression & inferior rotation of scapula
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serratus anterior origin
external surfaces of rib 1-8
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serratus anterior insertion
medial border of scapula
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serratus anterior action
holds scapula against thoracic wall
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latissimus dorsi origin
inferior three ribs; iliac crest
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latissimus dorsi insertion
intertubercular groove of humerus
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latissimus dorsi action
extension, medial rotation, & adduction of arm
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trapezium origin
posterior surface of occipital bone
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trapezius insertion
lateral third of clavicle
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trapezius action
elevate, retract, depress scapula
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teres major origin
scapula, near inferior angle
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teres major insertion
medial lip of intertubercular groove
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teres major action
extension, medial rotation of arm, adduction
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deltoid origin
lateral third of clavicle
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deltoid insertion
deltoid tuberosity of humerus
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deltoid action
medial rotation, flexion of arm
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levator scapulae origin
transverse process of vertebrae
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levator scapulae insertion
medial border of scapula
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levator scapulae action
elevates scapula
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rhomboid minor origin
spinous process of c7 & t1
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rhomboid minor insertion
medial border of scapula
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rhomboid minor action
elevates & retracts scapula
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rhomboid major origin
spinous process of t2-t5
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supraspinatus origin
supraspinous fossa of scapula
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supraspinatus insertion
greater tubercle of humerus
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supraspinatus action
abduction of arm
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infraspinatus origin
infraspinous fossa of scapula
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infraspinatus insertion
greater tubercle of humerus
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infraspinatus action
lateral rotation of arm
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subscapularis origin
subscapular fossa of scapula
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subscapularis insertion
lesser tubercle of humerus
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subscapularis action
adduction & medial rotation of arm
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teres minor origin
lateral border of scapula
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teres minor insertion
greater tubercle of humerus
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teres minor action
lateral rotation of arm
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