Bio 223 Week 7 pt 2 & 8

Muscle contractions 

Only pull/contact never push

One muscle takes action another does opposite

Fascicles

Bundles of muscle fibers

Circular

Fascicles arranged in rings

Orbicularis oris

Convergent

Broad origin with the fascicles coming together to a single tendon

Pectoralis

Parallel

Fascicles are parallel to a long axis, straplike muscle

Rectus Abdominis

Fusiform

Parallel fascicles spindle shaped muscle

Biceps brachi

Pennate

Short muscle fibers that attach to a tendon that is running along the length of the muscle

Has three forms

Unipennate

Fascicles only attach to one side of the tendon

Bipennate

Fascicles attach to the opposite sides of the tendon

Multipennate

feathory; attach to many places around tendon 

Deltoid 

short fibers 

Not as much range of motion

Longer fibers

Greater range of motion

Bipennate and multipennate

Shorten a little but are most powerful most muscle fibers

Agonist

Prime mover most responsible for making movement

Antagonist

Opposes or reverses prime mover

What helps prime movers?

Synergist

Makes movement more efficient

What gives prime movers a stable base?

Fixators

Keeps origin of muscle immobile

Origin

Place where muscle has a fixed attachment

Insertion

Place that moves when muscle is contracted