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INVOLUNTARY = work on their own without you thinking about them.
Also known as SMOOTH.
VOLUNTARY = work when you want them to
eg to catch a ball, brain sends a signal along the nervous system to the muscles needed for this job - muscles contract - pull on bones - movement occurs - catch the ball.
Also called SKELETAL because they are joind to bones and STRIPED muscle.
They are a special type of involuntary muscles that work non-stop. Each contraction is a heartbeat.
When a muscle contracts usually just one bone moves the other is stationary.
The ORIGIN is where the muscle tendon is joined to the stationary bone
The INSERTION is where the muscle tendon joins the moving bone.
WHEN A MUSCLE CONTRACTS THE INSERTION MOVES TOWARDS THE ORIGIN
when your biceps contract, the triceps relax
making the elbow flex and pulling up your forearm
to extend the elbow, the bicep relaxes and the triceps contract
This is called antagonistic muscle action
The muscle doing the work is the AGONIST (agony!) or the PRIME MOVER
The muscle which is relaxing is called the ANTAGONIST
When other muscles assist the prime mover in creating a movement, these muscles are called SYNERGISTS
