BIO21011 THE MUSCULAR SYSTEM

I.Lever systems

A. muscle moves bone around a joint

1.origin

2.insertion

3.belly

B. .lever

1.rigid bar = bone

C. fulcrum

1.fixed point = joints

D. effort

1.applied force = at insertion of muscle

2.with muscle contraction

E..load

1.resistance

2.bone and tissue or object

F.types

1.first class

a.L, F, E(down)

b.atlas, axis

2.second class

a.F, L. E(push up)

b.stand on toes

3.third class

a.most skeletal muscle

b.L,E(pull up), R

c.load at hand, effort biceps brachaii attached to forearm and pulls up when contracted,fulcrum is elbow

II. Fascicle arrangement

A. fibers in same direction

B. parallel

C. circular

III.Muscle Movements

A.prime mover = agonist

B.antagonist = oppose movement of prime mover

C.synergist = reduces undesirable movements

D.fixator= specialized synergist, immobilizes origin

IV.Naming of muscles

A.location

1.brachii

B.direction of muscle fibers

1.oblique

C.# of origins

1.bi or triceps

D.origin and insertion

1.sternocleidomastoid

E.shape

1.trapezius

F.action

1.adductor

V.A few important Muscles

A.zygomaticus

1.origin=zygomatic bone

2.insertion=orbicularis oris

3.action=smile

B.sternocleidomastoid

1.origin=sternum, clavical

2.insertion=mastoid

3.action=head moverment (rotation,extension)

C.deltoid

1.origin=scapula,clavicle

2.insertion=deltoid tuberosity of humerus

3.action=abduction, extension,flexion of humerus

D.biceps brachaii

1.origin=scapula

2.insertion=radius

3.action=flexor of lower arm

E.triceps brachii

1.origin=scapula,humerus

2.insertion=olecranon of ulna

3.action extends lower arm

F.hamstrings

1.origin=ischium

2.insertion=tibia

3.action= flexion at knee

G.quadriceps femoris

1.anterior thigh

a.four heads

(1)rectus femoris

(a)origin=iliac spin

(2)vastus lateralis,medialis, and intermedius

(a)origin=femur

2.insertion=patella to tibia

3.action=extension at knee

H.gastrocnemius

1.origin=lateral and medial condyles of femur

2.insertion=calcaneus

3.action=plantar flexion of foot