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Chapter 11 Biol 1190

Terms in this set (71)

muscular system
the voluntarily controlled muscles of your body compose
origin
the attachment of a muscle's tendon to the stationary bone
insertion
the attachment of the muscle's other tendon to the movable bone
belly
fleshy portion of the muscle between the tendons
actions
are the main movements that occur when the muscle contracts
lever
is a rigid structure that can move around a fixed point
fulcrum
a fixed point
effort
causes movement
load
resistance
mechanical advantage
the load is closer to the fulcrum and the effort farther from the fulcrum, then only a relatively small effort is required to move a large load over a small distance
mechanical disadvantage
the load is farther from the fulcrum and the eddoirt is applied closer to the fulcrum, then a relatively large effort is required to move a small load
first class levers
-fulcrum is between the effort and the load
-can either produce a mechanical advantage or a mechanical disadvantage
second class levers
the load is between the fulcrum and the effort
-always produce a mechanical advantage because the load is always closer to the fulcrum than the effort
-sacrifices speed and range of motion for forace
third class levers
-the effort is between the fulcrum and the load
-produce a mechanical disadvantage because the effort is always closer to the fulcrum than the load
- the arrangement favors speed and range of motion over force
prime mover
contracts to cause an action while the other
antagonist
stretches and yields to the effects of the prime mover
synergists
contract and stabilize the intermediate joints
fixators
stabilizing the origin of the prime mover
compartment
is a group of skeletal muscles, in which their associate blood vessels, and associated nerves, all of which have a common function
parallel
fascicles parallel to longitudinal axis of muscle; terminate at either end in flat tendons
fusiform
-fascicles nearly parallel to longitudinal axis
-terminate in flat tendons muscle tappers toward tendons, where diameter is less at belly
circular
fascicles in concentric arrangements from sphincter muscles that enclose an orifice ( opening)
triangular
fascicles spread over broad area converge at thick central tendon, gives muscle a triangular appearance
pennate
-short fascicles in relation to total muscle length
-tendon nearly extends entire length of muscle
unipennate
fascicles arranged on only one side of tendon
bipennate
fascicles arranged on both sides of centrally positioned tendons
multipennate
fascicles attach obliquely from many different to several tendons
How are skeletal muscles named?
1) muscle features, such as the pattern of muscle's fascicles
2) the size, shape, action, number of origins and location of muscles
3) the sites of origin and insertion of the muscle
aponeurosis
sheetlike tendon
epicranial aponeurosis
covers the superior and lateral surfaces of the skull
buccinator
forms the major muscular portion of the cheek
occipitofrontalis
draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead horizontally as in look of surprise
occipital belly
draws scalp posteriorly
orbicularis oris
closes and protrudes lips, as in kissing
- compresses lips against teeth
-shapes lips during speech
platysma
-draws outer part of lower lip inferiorly and posteriorly as in pouting
-depresses mandible
orbicularis oculi
closes eye
masseter
elevates mandible, as in closing mouth
sternocleidomastoid
-laterally rotate and flex head to opposite side of contracting muscles
-posterior fibers of muscle can assist in extension of head
rectus abdominis
-flexes vertebral column, especially lumbar portion
-compresses abdomen to aid in defecation, urination, forced exhalation, and childbirth
external oblique
-acting together
- compresses abdomen and flex vertebral column
-laterally flex vertebral column, especially lumbar portion and rotate vertebral column
internal oblique
-compresses abdomen and flex vertebral column
-rotates vertebral column
transverus abdominis
compresses abdomen
diaphragm
-contraction of it causes it to flatten and increases vertical dimension of thoracic cavity, resulting in inhalation
-relaxation of diaphragm causes it to move superiorly and decreases vertical dimension of thoracic cavity
serratus anterior
-abducts scapula and rotates it upward
-elevates ribs when scapula is stabilized
-known as boxer's muscle because it is important in horizontal arm movements such as punching and pushing
trapezius
-superior fibers upward rotate scapula;
-middle fibers adduct scapula
-inferior fibers depress and upward rotate scapula
elevation
superior movement of the scapula, such as struggling the shoulders or lifting a weight over the head
depression
inferior movement of the scapula, as in pulling down on a rope attached to a pulley
abduction
movement of the scapula laterally and anteriorly
adduction
movement of the scapula medially and posteriorly, as in pulling the oars in the rowboat
upward rotation
movement of the inferior angle of the scapula laterally so that the glenoid cavity is moved upward
downward rotation
movement of the inferior angle of the scapula medially so that the glenoid cavity is moved downward
pectoralis major
-adducts and medially rotates arm at shoulder joint
-clavicular head flexes arm and sternocostal head extend flexed arm to side of trunk
latissimus dorsi
extends, adducts, and medially rotates arm at shoulder joint
-draws arm inferiorly and posteriorly
deltoid
-lateral fibers abduct arm at shoulder joint
-anterior fibers flex and medially rotate arm at shoulder joint
biceps brachii
-flexes forearm at elbow joint,
-supinates forearm at radioulnar joints
-flexes arm at shoulder joint
brachialis
flexes forearm at elbow joint
brachioradialis
-flexes forearm at elbow joint
-supinates and pronates forearm at radioulnar joints to neutral position
triceps brachii
extends forearm at elbow joint and extends arm at shoulder joint
gluteus maximus
-extends thigh at hip joint and laterally rotates thigh
-hels lock knee in extension
gluteus medius
abducts thigh at hip joint and medially rotates thigh
gluteus minimus
abducts thigh at hip joint and medially rotates though
rectus femoris
-all four heads extends leg at knee joint
-rectus femoris muscle acting alone also flexes
vastus lateralis
-all four heads extends leg at knee joint
-rectus femoris muscle acting alone also flexes
vastus medialis
-all four heads extends leg at knee joint
-rectus femoris muscle acting alone also flexes
vastus intermedius
-all four heads extends leg at knee joint
-rectus femoris muscle acting alone also flexes
biceps fermoris
flexes leg at knee joint and extends thigh at hip joint
semitendinosus
flexes leg at knee joint and extends thigh at hip joint
semimembranosus
flexes leg at knee joint and extends thigh at hip joint
tibialis anterior
dorsiflexes foot at ankle joint and inverts (supinates) foot at intertarsal joints
gastrocnemius
plantar flexes foot at ankle joint and flexes leg at knee joint
soleus
plantar flexes foot at ankle joint
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