Introduction to the Muscular System

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Muscle Types Skeletal – Moves bones Smooth – moves internal organs Cardiac – moves heart

Skeletal Muscles Enable movement by pulling bones Made mostly of proteins Striated – lines or stripes on tissue that make it strong and enable it to contract Exert large forces for a short period of time Strong but get tired easily Voluntary

Skeletal Muscle types Flexors and extensors - work in opposing pairs - one contracts and the other relaxes - responsible for gross motor movement like dancing, walking, - responsible for fine motor movement like writing, painting, playing video games

Skeletal Muscle Types Levators and Depressors - levator = lifting - depressors = bringing back down

Muscle pairs

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Smooth Muscle Not striated Apply weaker forces Have great endurance – can work for a long period of time without a lot of rest – digestion can take up to 8 hours! Involuntary Found in the internal organs – digestive organs and blood vessels

Cardiac Muscle Some striations Found ONLY IN THE HEART! Strong force and great endurance Continuously working!!!

All Muscle Cells Must Rest!