Chapter 6 The Muscular System 203 Copyright Goodheart-Willcox Co., Inc. 15. Rectus femoris 16. Temporalis 17. Pectoralis major 18. Tibialis anterior 19. External oblique 20. A muscle _____ may be classified as grade I, II, or III. 21. The process before birth in which muscle tissue begins to form from stem cells is called _____. 22. A mature muscle cell is known as a(n) _____. 23. A(n) _____ is a bruise or bleeding within a muscle. 24. A complication that can arise from a contusion is _____. 25. Which of the following is not a typical cause of cramps? A. electrolyte imbalance B. dehydration C. deficiency in minerals such as calcium or potassium D. lack of aerobic exercise Thinking Critically 26. Discuss in depth the differences between concentric, isometric, and eccentric contractions and provide examples of how each one is used in daily life. 27. What do you think would be the pros and cons of body organs being made up exclusively of voluntary muscle (no involuntary muscle)? Provide specific examples and some pros and some cons for each. 28. Describe the structure of skeletal muscle. 29. Discuss muscle fiber arrangements that contribute to the force a muscle can generate. 30. How do you think slow-twitch muscle fibers are usually arranged? Give reasons for your answer. 31. Who generates more power: An Olympic weightlifter who must lift 400 pounds from the ground to a position over his head very rapidly, or a power lifter who must squat down and stand up with 800 pounds on his back? Defend your answer. 32. Discuss how torque is used to measure the strength of a muscle group at a specific joint. 6. The ability of a muscle and other tissue to be stretched is the behavioral characteristic known as _____. A. extensibility B. elasticity C. irritability D. contractility 7. The ability of a muscle to respond to stimuli is the behavioral characteristic known as _____. A. extensibility B. elasticity C. irritability D. contractility 8. A nerve that stimulates skeletal muscle is called a(n) _____. 9. The functional unit of the neuromuscular system is the _____. 10. A(n) _____ is an electrical charge that creates tension within a muscle fiber. 11. _____-twitch muscle fibers contract powerfully but fatigue quickly. Instructions: Write the letter of the name of the muscle next to the corresponding number. A H G E F D B C 12. Deltoid 13. Abdominal aponeurosis 14. Biceps brachii