1. Muscle Tissue & Basic Muscle Anatomy p. 178-184 NOTE: Myo-, mys-, & sarco- : All refer to muscle!

2. Properites of Muscle Tissue • Irritability / excitability • Neurotransmitter • Change in pH • Contractility • Extensibility • Elasticity • Know the 3 types & their characteristics!

3. Functions of the Muscular System • Produces movement • Maintains posture • Stabilizes joints • Generates heat • Byproduct of using ATP (energy) for skeletal muscle contraction • Other: • Protection • Valves – regulate movement

4. Muscle Anatomy • Muscle cells are bundled together to form fascicles • Connective tissue wrappings: • Endomysium • Perimysium • Epimysium • Continuous with tendons and aponeuroses

5. Tendons • Structure: • Dense connective tissue (collagen fibers) • Functions: • Attach muscles to bone, cartilage, or connective tissue • Conserve space across joints • Durable enough to cross rough bony projections

6. Aponeuroses

7. Parts of a Muscle Cell • Muscle fiber= muscle cell • Sarcoplasm = cytoplasm • Sarcolemma = cell membrane • T tubules – extensions of sarcolemma into sarcoplasm • Myofibrils = organelles containing contractile proteins • Sarcoplasmic reticulum (SR) = smooth endoplasmic reticulum (SER) • Contains Ca2+ ions • Surrounds myofibrils & T tubules

8. A Muscle Fiber

9. Myofibril – teased out of cell

10. Myofilaments • Protein filaments that make up a myofibril • 2 main proteins: • Actin • Thin filaments • Myosin • Thick filaments • 3-D arrangement

11. Sarcomere • Functional (contractile) unit of muscle • Many sarcomeres lined up end-to-end make a myofibril • Made of myofilaments • Z disc to Z disc

12. Striations • Light (I) bands • Only actin • Dark (A) bands • Actin & myosin • Z line • Middle of I band • H zone • Only myosin • M line • Middle of H zone

13. Muscle Fascicles Muscle Fibers Myofibrils Myofilaments