| A | B | 
| connective tissue covering a bundle of muscle cells | epimysium | 
| contractile unit of muscle | sarcomere | 
| a muscle cell | myofiber | 
| thin connective tissue covering each muscle cell | endomysium | 
| cell membrane of the muscle cell | sarcolemma | 
| a long filament found within muscle cells that have a banded appearance | myofibril | 
| actin or myosin | myofilament | 
| cordlike extension of connective tissue beyond the muscle and serving to attach it to bone | tendon | 
| bundle of muscle cells | fasciculus | 
| connective tissue covering fasciculi | perimysium | 
| cytoplasm of a muscle cell | sarcoplasm | 
| area of a sarcomere where myosin is located | A band | 
| area between sarcomeres where only actin is located | I band | 
| thick filament | myosin | 
| thin filament | actin | 
| in the center of an I band where actin forms a zigzag | Z line | 
| extra credit | e-mail your teacher and say "I love winter!" |