bio chap 10b terms

each muscle has ____ sites of attachment

two

origin

proximal site where the muscle is attached tp a more stationary bone

insertion

distal site where a muscle is attached to a more movable bone

belly

the portion of the muscle between the origin and insertion (aka gaster)

lever

a rigid rod that moves around a fixed point called the fulcrum

effort

applied force which causes the movement

resistance (load)

the object being moved

first class lever

fulcrum is between the resistance and the effort

second class lever

resistance is between the fulcrum and effort

third class lever

effort is between the fulcrum and resistance

flexion

reduction in the angle of a joint

extension

an increase in the angle of a joint

elevation

any upward movement

depression

any downward movement

abduction

a movement away from the midline of the body or body part

adduction

a movement toward the midline of the body or body part

inversion

turning the sole of the foot inward

eversion

turning the sole of the foot outward

protraction

any forward movement of a joint in a horizontal plane

retraction

any backward movement of a joint in a horizontal plane

pronation

turning the palms down, or posteriorly

supination

turning the palms up, or anteriorly

dorsiflexion

movement of the foot up or toward the shin

plantar flexion

movement of the foot downward

external rotation

moving away from midline

internal rotation

moving back to midline

rotation

movement of a bone around its long axis

circumduction

movement in which the proximal end of a limb is stationary while the distal end moves in a circle; a cone-like movement.

action

the body movement produced when a muscle contracts

the prime mover (aka agonist)

the muscle primarily responsible for producing the body movement

the antagonist

a muscle that opposes the action of a prime mover

synergist

a muscle, or group of muscles that help the prime mover by providing additional pulling force/stabilizing a joint

fixator

a muscle, or group of muscles that aid the prime mover specifically by stabilizing the point of origin of a prime mover

maximus

largest

minimus

smallest

longus

long

biceps

two heads, or origins

triceps

three heads, or origins

mechanical advantage

the amount by which a simple machine multiplies an applied force or effort

rectus

fibers run parallel to the imaginary line (straight)

oblique

muscle’s fibers run slanted to the imaginary line

deltoid

“triangular”

* direction
* size
* location
* number of origins
* location of origin/insertion
* shape
* action

naming skeletal muscles:

* rigid rod
* fulcrum
* effort
* resistance (load)

components of a lever:

* allow a given effort to move a heavier load
* allow a given effort to move a load farther than it otherwise would

advantages levers provide:

origin (manubrium, clavicle) and insertion (mastoid process)

sternocleidomastoid named from:

example of agonist

biceps brachii (elbow flexion), rectus femoris (extension of knee)

example of antagonist

triceps brachii to biceps brachii

example of synergist

vastus lateralis, vastus medialis, vastus intermedius

example of fixator

rotator cuff (sits muscles -supraspinatus, infraspinatus, teres minor, suprascapularis)