Chapter 11: Muscle 1. What is the special term for the cytoplasm of muscle cells? 2. What are the three categories of striated muscle? 3. What is the difference between skeletal muscle and visceral striated muscle? 4. Where are smooth muscles found? 5. How do skeletal myofibers come to be multinucleated? 6. What shape do skeletal myofibers have in cross section? 7. Where are the nuclei of skeletal myofibers located? 8. What are the locations of endomysium, perimysium, and epimysium? 9. Does H&E staining allow one to recognize red, white, and intermediate myofibers? 10. What is the role of myoglobin? 11. How does the myoglobin and mitochondrial content of red myofibers make them particularly well suited as postural muscles?. 12. How do the dimensions of red myofibers compare with white myofibers? 13. What is a myofiber? (Not explicit in text.) 14. What is a myofibril? 15. What are myofilaments and how are they related to myofibrils? 16. What special name is given to the endoplasmic reticulum of skeletal myofibers? 17. What gives myofibrils a striated appearance? 18. What lines and bands are visible with light microscopic examination of a sarcomere? 19. What is a sarcomere? What forms the ends of a sarcomere? 20. How long is a sarcomere in a relaxed mammalian skeletal myofiber? 21. Which of the myofilaments corresponds to the A band? 22. What attaches to the Z line? 23. Which of the myofilaments occupies the I band and extends all the way to the H band? 24. What three types of proteins comprise the thin filament? 25. During a muscle contraction, how do the dimensions of the A band, the I band, and the H band change? 26. What is the role of the sarcoplasmic reticulum and terminal cisternae? 27. What is the role of the T-tubule in striated myofibers? 28. What are the two names for the contact between a motor neuron and a skeletal myofiber? 29. What neurotransmitter is released at that synapse? 30. What is a motor unit? 31. What happens to muscle fibers deprived of their innervation? 32. What is the location and role of satellite cells? 33. What determines whether damaged muscle is replaced with new muscle tissue or scar (connective) tissue? 34. What structure, unique to cardiac muscle, is useful in recognizing this type of muscle tissue? 35. Cardiac myofibers are said to be “branched.” What structure connects one cardiac myofiber to another at one of these branch points? 36. Where is the nucleus of a cardiac myofiber normally located inside the cell? 37. What are the components of the intercalated disk as resolved in electron microscopy? 38. Which component of the intercalated disk allows an action potential to spread from myofiber to myofiber in the heart? 39. As a result of a myocardial infarction, what type of tissue typically replaces the cardiac myofibers that die as a result of the infarction? 40. What is the shape of smooth myofibers? 41. How does the cytoplasmic staining of smooth myofibers compare with that of striated myofibers? 42. What is the usual location and appearance of a nucleus in a smooth myofiber? (Consider as seen in longitudinal and cross sections.) 43. How can smooth muscles be distinguished from fibroblasts in routine H&E material? 44. How is it that smooth muscles use only about 10% of the ATP that would be required by a striated muscle to do the same work? 45. How does the innervation of smooth muscle differ from that of skeletal muscle in terms of the sources of nerves and the location of neurotransmitter release? 46. What is a nexus and what is the function of a nexus? 47. What types of cells can serve as the precursors to smooth myofibers in adults and following injury?