| A | B |
| muscle | organ that can relax, contract, and provide the force to move your body parts |
| voluntary muscles | muscles you are able to control |
| involuntary muscles | muscles you can't control consciously |
| skeletal muscles | muscles that move bones |
| cardiac muscle | striated muscle found only in the heart |
| smooth muscle | nonstriated muscle that makes up internal organs |
| tendons | thick bands that attach muscles to bones |
| contraction | when muscles shorten to create movement |
| relaxation | when muscles lengthen to create movement |