1. Lecture Presentation by Lee Ann Frederick University of Texas at Arlington Chapter 10 Muscle Tissue © 2015 Pearson Education, Inc. (heavily modified by GJC)

2. An Introduction to Muscle Tissue Review (from Chapter 4): What are the 3 types of muscle tissue and what are the differences among them?

3. 10-1 Functions of Skeletal Muscle Tissue Functions of Skeletal Muscle Tissue

4. © 2015 Pearson Education, Inc. SKELETAL MUSCLE (organ) FASCICLE (bundle of fibers) MUSCLE FIBER (cell) 10 th Martini, Figure 10-1

5. © 2015 Pearson Education, Inc. Figure 10-2a The Formation of a Multinucleate Skeletal Muscle Fiber. Myoblast Muscle fibers develop through the fusion of embryonic cells called myoblasts. Mature muscle fiber Myosatellite cell Immature muscle fiber

6. Why (some) muscles look striated (striped) http://en.wikipedia.org/wiki/Sarcomere

7. © 2015 Pearson Education, Inc. Figure 10-5 Sarcomere Structure, Superficial and Cross-Sectional Views. Sarcomere

8. How muscles contract: a multi-step overview 1. A motor neuron transmits A-C-h; A-C-h opens sodium channels; 2. Sodium causes depolarization; Depolarization triggers the SR…. 3. And the SR releases calcium ions, And the calcium ions bind to troponin, 4. And troponin gives tropomyosin a tug, And tropomyosin accommodates myosin, 5. And myosin pulls on the actin, child -- The myosin pulls on the actin.

9. http://www.noteflight.com/scores/view/5a4cd6a620007ba4b24b5e15d5c58196e238927a

10. The neuromuscular junction (Figure 10-9) © 2015 Pearson Education, Inc. Arriving action potential Na + ACh receptor 1 2 3

11. © 2015 Pearson Education, Inc. Figure 10-10 Excitation-Contraction Coupling.

12. [Space to take notes on previous figure]

13. The contraction cycle (Figure 10-11) 1 2 3 white ovals = ADP + P i (breakdown products of ATP)

14. The contraction cycle (Figure 10-11) 4 5 6 yellow ovals = ATP

15. Where in the contraction cycle will a “fresh” dead person’s muscles stop?

16. © 2015 Pearson Education, Inc. Figure 10-12 Shortening during a Contraction. When both ends are free to move, the ends of a contracting muscle fiber move toward the center of the muscle fiber. a When only one end of a myofibril is fixed in position, the free end is pulled toward the fixed end. b

17. How does a muscle contraction END?

18. The effect of sarcomere length on muscle force (like Figure 10-14) Figure: Principles of Physiology by Cindy L. Stanfield

19. © 2015 Pearson Education, Inc. Figure 10-17a The Arrangement and Activity of Motor Units in a Skeletal Muscle. Muscle fibers Axons of motor neurons Motor nerve SPINAL CORD Motor unit 1 Motor unit 2 Motor unit 3 KEY

20. How do we adjust a muscle’s level of force? (2 basic ways)

21. © 2015 Pearson Education, Inc. Figure 10-18 Concentric, Eccentric, and Isometric Contractions. Tendon 2 kg 6 kg

22. Why are eccentric contractions clinically interesting?

23. © 2015 Pearson Education, Inc. Figure 10-20 Muscle Metabolism. Fatty acids O2O2 Glucose Glycogen ADP ATP To myofibrils to support muscle contraction CO 2 Pyruvate ATP ADP

24. 3 key components of muscle ComponentFunctionEffect of strength training Effect of endurance training Contractile proteins (actin/myosin) Sarcoplasmic Reticulum (SR) Mitochondria

25. Changes in SR? Look at evolution… P.J. Schaeffer et al., Journal of Experimental Biology (1996)