1. The Muscular System

2. Review of Muscle Types

3. Characteristics Excitability Contractibility Extensibility Elasticity

4. Functions Movement Posture Joint stability Heat production

5. Whole muscle structure

6. Skeletal muscle attachment Direct attachment Indirect attachment Tendon Aponeurosis

7. Skeletal muscle fiber (cell)

9. Muscle Contraction Stimulus Begins with stimulation of motor neurons

10. Sliding Filament Theory Impulse travels to axon terminal and releases acetylcholine Sarcolemma composition is altered and sends message down T tubules to release Ca 2+ Increased calcium levels open myosin binding sites on actin and ATP is broken down to energize myosin

12. Myosin binds to actin creating a cross bridge resulting in a connection that allows a “power stroke” to occur ATP rebinds with myosin head, breaking attachment This process continues while calcium and/or ATP levels are sufficient Results in shortening of sarcomere

13. Sarcomere contraction video http://www.youtube.com/watch?v=83yNo EJyP6g&feature=related http://www.youtube.com/watch?v=83yNo EJyP6g&feature=related

14. Substances used to provide energy during muscle contraction ATP Creatine phosphate Fatty acids and glucose