Movements – - voluntary – intend to make; ex. walking - involuntary – you do not control; ex. breathing
Skeletal – - voluntary movement; attached to bone - made of protein fibers – actin and myosin - work together to allow muscle to contract and relax - myofibrils – makes light & dark bands in muscle = striations
Smooth – - not voluntary; found in internal organs - no striations
Cardiac – - not voluntary; found only in heart - striated; complex
Actin & myosin not connected when muscle is relaxed When contracts, myosin attaches to actin, forming a bridge Bridge pulls actin, muscle shortens (contracts) Cells use ATP to break and rebuild bridges
No oxygen, no ATP, no relaxing muscles Rigor mortis = process when muscles stiffen Begins ~ 2 hours after death Begins in small muscles in face Takes ~ 12 hours for whole body Can last hours Eases w/ decaying body