Chapter 10: Muscular system Flashcards
muscles account for roughly __ % of body weight
50
performance of muscles varies based on __ and __
fiber organization, skeletal attachments
what are the two divisions of the skeletal muscle system?
axial and appendicular
what is the function of axial muscles?
support and position axial skeleton
what is the function of appendicular muscles?
support, move, and brace limbs
what is a fascicle?
a bundle of muscle fibers
the fascicles in a parallel muscle are__
parallel to long axis
give an example of a parallel muscle
biceps brachii
how much do parallel muscles shorten?
~30%
describe structure of convergent muscle
fascicles extending over broad area, converging at common attachement point
which pulls harder? Convergent or parallel muscles?
parallel
give an expample of a convergent muscle
pectoralis major
structure of pennate muscle
fascicles form angle with tendon
do tendons move more in parallel or pennate muscles?
parallel muscles
pennate muscles have more ___ than same-sized parallel muscle
myofibrils/fibers
which produces more tension, parallel or pennate?
pennate
what are the 3 types of pennate muscles?
- unipennate
- bipennate
- multipennate
structure of unipennate muscles?
all fibers on one side of tendon
give an example of unipennate muscle
extensor digitorum
structure of bipennate muscle
fibers insert on both sides of tendon
give example of bipennate muscle
rectus femoris
structure of multipennate muscle
tendon branches within pennate muscle
give an example of multipennate muscle
deltoid
structure of circular/ spinchter muscles
concentric rings of fascicles
give an example of circular muscle
orbicularis oris
what is a lever?
rigid structure that moves when force applied overcomes the load
what is a fulcrum?
a fixed point on which a lever pivots
what is a first class lever?
fulcrum between AF and L
example of 1st class lever in body
splenius capitis and semispinalis capitis muscles
what is a 2nd class
load between AF and f
what is a 3rd class lever?
fulcrum, af, load
example of 1st class lever in body
neck extension at atlanto-occipital joint
example of second class lever in body
plantar flexion at ankle joint
example of third class lever in body
flexion at elbow
thrid class levers have increased __ and ___, but decreased ___
speed and distance, force
second class levers have increased __, but decreased ___ and __
force; speed and distance
origin
where muscle attaches
most origins are __, but can be __-
bones, but can be connective tissue
where is the origin in relation to the insertion?
proximal
insertion
where movable end of muscle attaches
agonist
prime mover
what is the agonist in elbow flexion?
biceps brachii
synergist
muscle that helps prime mover
synergist in elbow flexion
bracioradialis
antagonist
muscle whose action opposes that of the prime mover
antagonist in elbow flexion
triceps brachii
deltoid
triangle
orbicularis
circle
brevis
short
longissimus
longest
longus
long
major
larger
maximus
largest
vastus
great
levator
raising
what is the originof muscles in facial expression?
skull
what are the insertions for muscles in facial expression?
superficial fascia and dermis of skin
what are the origins of the extrinsic eye muscles?
sphenoid and maxillary bone around optic canal
what are the 6 extrinsic eye muscles?
- superior oblique
- inferior oblique
- superior rectus
- lateral rectus
- medial rectus
- inferior rectus
action of inferior rectus
eye looks down
action of medial rectus
eye looks medially
action of superior rectus
eye looks up
action of lateral rectus
eye looks laterally
action of superior oblique
eye rolls: looking down and lateral
action of inferior oblique
eye rolls: looking up and laterally
which 2 muscles are involved in chewing?
masseter and temporalis
action of masseter in chewing
raises mandible and closes jaw
action of temporalis in chewing
raises mandible
which 3 muscles are closely associated with chewing?
- tongue
- of pharnyx (swallowing)
- of neck
muscles of the vertebral column originate and insert where?
vertebral processes
there are few __ in vertebral muscle
flexors
what are the 3 main muscles of the abdomen?
- external oblique
- internal oblique
- rectus abdominis
muscles of the appendicular skeleton are grouped by ___ and ___
actions and origins
muscles of the pectoral girdles originate __ and insert __
on axial skeleton; on clavicle/scapula
muscles that ove the arm originate __ and insert __
on pectoral girdle and rib cage; on humerus
muscles that move the forearm and hand originate __ and insert __
on pectoral girdle and arm; on radius, ulna, and/or carpels
extrinsic muscles to the hand originate __ and insert __
on humerus, radius, ulna; on metacarpals and phalanges
intrinsic muscles of the hand originate __ and insert __
on carpals and metacarpals; on phalanges
muscles that move the thigh originate __ and insert __
in pelvic region; on femur
muscles that move the leg originate __ and insert __
on pelvis and femur; on tibia/fibula
extrinsic muscles that move the foot/toes originate __ and insert __
on tibia/fibula; on tarsals, metatarsals, plalanges
intrinsic muscles that move the foor/toes originate __ and insert ___
on tarsals, metatarsals; phalanges
the largest appendicular muscles originate __
on the trunck
trunck muscles control ___ scale movement
large
structure of muscles of the trunk
large and powerful
what are the 2 largest superficial muscles involved in arm movement?
latissimus dorsi and deltoid
what are the four rotator cuff muscles?
- supraspinatus
- infraspinatus
- teres minor
- subscapularis
wrist extensors can be seen on what surface?
posterior surface
wrist flexors can be seen on what surface?
anterior surface
what are the extensor and flexor retinaculum?
wide band of connective tissue holding tendons of muscles in place
the biceps brachii origin is __ and inserts on __
scapula; radius
action of biceps bracii
flexion of elbow
the brachioradiallis origin is __ and inserts on__
humerus; radius
action of brachioradiallis
elbow flexion
brachiallis origin is __ and inserts on __
humerus; ulna
the triceps bracii origin is __ and inserts on __
scapula/humerus; ulna
action of triceps brachii
extension of elbow
flexors are mostly __ and __
anterior and medial
extensors are mostly __ and __-
posterior and lateral
what are synovial tendon sheaths?
tubular bursae surrounding tendons where theu cross bony surface
carpal tunnel syndrome is caused by inflammation of __
flexor retinacculum and synovial sheaths
flexors of the knee originate __ and extend along __ and __ surfaces of the thigh
on pelvic girdle; posterior and medial
extensors of the knee originate ___ and extend along __ and __ surfaces of the thigh
femoral surface; anterior and lateral
what is the quadriceps femoris?
collective name for the 4 knee extensors that all insert on quad
how many vastus muscles surrounf the rectus femoris?
3
all 4 quad muscles insert on the __
patella
what are the 3 flexors of the knee?
- biceps femoris
- semimembranosus
- semitendinosus
the biceps femoris inserts
tibia
the semimembranosus inserts on
tibia
the semitendinosus inserts on
tibia
what are the 4 extensors of the knee?
- rectus femoris
- vastus intermedius
- vastus lateralis
- vastus medialis
where do the 4 knee extensors insert?
patellar ligamnet
what are the 2 largest muscles involved in ankle movement?
gastrocnemius and soleus
what are intermuscular septa?
fibrous parttions that separate limb muscles into differnet compartments
each compartment has:
- muscles sharing common functions
2. its own blood and nerve supply
what is compartment syndrome?
trauma to limb can cause bleeding, which compresses bv and a lack of blood causes starvation and death
