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Muscular System Ch 11.

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Presentation on theme: "Muscular System Ch 11."— Presentation transcript:

1 Muscular System Ch 11

2 Origin- fixed point of attachment; for biceps brachii O= clavicle and humerus
Insertion- moveable, usually crosses a joint; O= radius Prime mover- - muscle group responsible for producing particular movement Antagonist- works opposite of prime mover Synergist-reduces undesirable or unnecessary movement Contraction of a muscle crossing 2 or more joints would cause movement of all if synergists weren’t there to stabilize it Ex. make a fist without bending wrist Fixator- specialized synergist- helps maintain posture; ex. muscles of the back fix scapula


4 Lever Systems Lever systems:
lever - rod that moves at the fulcrum (fixed point) fulcrum (F) typically the joint moving Resistance (R)- gravity pulling on body Effort (E)- muscle contraction Movement occurs when E > R First class levers - E F R Second class levers - F R E Third class levers - F E R . . (most common)

5 Lever Systems 1st class lever 2nd class lever 3rd class lever

6 biceps (flexor) triceps (extensor) triceps (extensor) Antagonistic
Muscles triceps (extensor) biceps (flexor)

7 Naming Skeletal Muscles
Direction of muscle fibers- straight, transverse Size of muscles- maximus, minimus, longus, brevis Location- frontalis, temporalis, occipitalis # of origins- biceps, triceps, quadriceps location of muscles origin and insertion- sternoclediomastoid- O= sternum and clavicle, I = mastoid process of temporal bone shape of muscle- deltoid- triangle shape, trapezius- trapezoid shape action of muscle- adductor muscle (adducts, brings in thigh)

8 Frontal Obicularis oculi Temporalis Obicularis oris Masseter Sternoclediomastoid









17 Masseter sternocledeomastoid Frontalis aponerosa Orbicularis oculi
temporalis zygomaticus Orbicularis oris Masseter sternocledeomastoid


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