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Unit 6 Vocab
Unit 6 Vocabulary
| Term | Definition |
|---|---|
| Epimysium | Connective tissue sheath that surrounds the entire muscle, separating it from other muscles. |
| Fascicle | Bundle of muscle fibers |
| Perimysium | Connective tissue sheath that surrounds each fascicle in a muscle. Limits friction between fascicles during contraction |
| Endomysium | Connective tissue sheath that surrounds each muscle fiber in the fascicle. |
| Sarcolemma | The plasma membrane of a muscle fiber. It is found under the endomysium. |
| Myofibril | Long proteins that make up muscle fibers |
| Sarcomere | Smallest unit of contraction in muscles |
| Myofilaments | Parts of a sarcomere responsible for contraction. Examples: Actin and Myosin |
| Neuromuscular Junction | The place where a motor nerve meets muscle fibers. Releases acetylcholine to contract muscles. |
| Action Potential | The electrical impulse that travels down a motor nerve, to the muscle, to cause contractions |
| Sarcoplasmic Reticulum | Organelle in muscles fibers, that when stimulated by the action potential, will release calcium ions needed to contract the muscle. |
| H Zone | Section of a sarcomere with only Myosin filaments. |
| I Band | Section of a sarcomere with only Actin filaments. |
| M Line | The midpoint of the myosin |
| A Band | Section of the Sarcomere where Myosin and Actin overlap. |
| Actin | Thin myofilament, shaped like two strings of pearls |
| Z Line | Boundaries of a sarcomere. Connects the Actin together |
| Myosin | Thick myofilament, with "heads" that grip to Actin during contraction. |