Pearson eText Human Anatomy & Physiology -- Instant Access (Pearson+)
2nd Edition
ISBN: 9780136873822
Author: Erin Amerman
Publisher: PEARSON+
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Chapter 10, Problem 1CYU
Summary Introduction
To review:
Whether large motor units are present in the postural muscles of the back or the muscles of the hand. Also, mention the rationale behind this.
Introduction:
A motor unit of the muscle comprises a motor neuron and skeletal muscle fibers innervated by the axon terminals of the motor neuron. The size of the motor unit depends on the factors like type of muscle, type of work accomplished by the muscle, and location of the muscle. Fine control of the movements is important in determining the size of a motor unit.
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Students have asked these similar questions
Would you expect to find larger motor units in the postural muscles of the back or the muscles of the hand? Explain your answer
Explain why the ratio of motor neurons to skeletal muscle fibers is greater in muscles that control eye movement than in postural muscles of the leg.
To demonstrate muscle fatigue, a student held an 8 lb dumbbell in her hand and abducted her arm parallel to the floor. After 45 seconds, she has having difficulty holding that position so she rotated her hand 90 degrees. This allowed her to hold the dumbbell in position for an additional 20 seconds. Which of the following is the best explanation for this?
A.
Different motor units were contracting while others were relaxing.
B.
Muscles began to contract isotonically rather than isometrically.
C.
The load was reduced.
D.
The resistance to contraction was reduced.
E.
The change in position provided a greater range of motion at the shoulder.
Chapter 10 Solutions
Pearson eText Human Anatomy & Physiology -- Instant Access (Pearson+)
Ch. 10.1 - What are the two types of striated muscle?Ch. 10.1 - Which two types of muscle are involuntary?Ch. 10.1 - What is the basic function of all types of muscle...Ch. 10.1 - 4. What five properties are common to all muscle...Ch. 10.1 - Prob. 5QCCh. 10.2 - Prob. 1QCCh. 10.2 - How are the terminal cisternae related to the...Ch. 10.2 - Prob. 3QCCh. 10.2 - How does the arrangement of myofilaments produce...Ch. 10.2 - 5. Describe the structure of a sarcomere. What is...
Ch. 10.2 - Prob. 6QCCh. 10.2 - Describe the structures of thin filaments, thick...Ch. 10.2 - Prob. 8QCCh. 10.3 - What is the resting membrane potential?Ch. 10.3 - Prob. 2QCCh. 10.3 - 3. How do the electrochemical gradients for...Ch. 10.3 - What two factors generate the resting membrane...Ch. 10.3 - What is an action potential?Ch. 10.3 - What happens during the two phases of an action...Ch. 10.4 - Prob. 1QCCh. 10.4 - Prob. 2QCCh. 10.4 - 3. How does excitation from a neuron trigger...Ch. 10.4 - How are excitation and contraction coupled?Ch. 10.4 - What are the steps of the crossbridge cycle?Ch. 10.4 - Prob. 6QCCh. 10.5 - What are the two immediate energy sources for...Ch. 10.5 - How long can these immediate energy sources fuel...Ch. 10.5 - Prob. 3QCCh. 10.5 - Prob. 4QCCh. 10.5 - Prob. 5QCCh. 10.5 - Prob. 6QCCh. 10.5 - Prob. 7QCCh. 10.6 - What is a twitch contraction?Ch. 10.6 - What are the phases of a twitch contraction?Ch. 10.6 - How does the timing of a stimulus impact the...Ch. 10.6 - 4. How do fused and unfused tetanus differ?
Ch. 10.6 - 5. At what length will a sarcomere be able to...Ch. 10.6 - How do type I and type II muscle fibers differ?Ch. 10.7 - Prob. 1QCCh. 10.7 - 2. Explain the process of recruitment.
Ch. 10.7 - Prob. 3QCCh. 10.7 - 4. How do isotonic concentric, isotonic...Ch. 10.8 - Prob. 1QCCh. 10.8 - Prob. 2QCCh. 10.8 - Prob. 3QCCh. 10.8 - What conditions does excess postexercise oxygen...Ch. 10 - Mark the following statements as true or false. If...Ch. 10 - How does a skeletal muscle fiber differ...Ch. 10 - Thick filaments are composed of the protein a....Ch. 10 - Prob. 4CYRCh. 10 - Prob. 5CYRCh. 10 - Mark the following statements as true or false. If...Ch. 10 - Prob. 7CYRCh. 10 - 8. Order the following events of excitation and...Ch. 10 - 9. Which of the following statements accurately...Ch. 10 - 10. A muscle fiber relaxes when:
a. the...Ch. 10 - Which of the following energy sources would...Ch. 10 - 12. Mark the following statements as true or...Ch. 10 - Prob. 13CYRCh. 10 - 14. Muscle tone is:
a. the result of voluntary...Ch. 10 - Prob. 15CYRCh. 10 - Which of the following is not likely to result...Ch. 10 - Which of the following factors is/are responsible...Ch. 10 - 18. What is thought to cause excess postexercise...Ch. 10 - Prob. 19CYRCh. 10 - 20. Which of the following best describes...Ch. 10 - Mark the following statements as true for smooth...Ch. 10 - Prob. 1CYUCh. 10 - Prob. 2CYUCh. 10 - 3. The drug neostigmine blocks the activity of...Ch. 10 - Explain why cardiac muscle cells and some smooth...Ch. 10 - Prob. 1AYKACh. 10 - Prob. 2AYKACh. 10 - Prob. 3AYKACh. 10 - Prob. 4AYKACh. 10 - Prob. 5AYKBCh. 10 - Prob. 6AYKB
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- What is a motor unit? Why does a rapid series of muscle twitches yield a stronger overall contraction than a single twitch?arrow_forwardWhy does a motor unit of the eye have few musclefibers compared to a motor unit of the leg?arrow_forwardWhat differences would you expect to see between amotor unit where muscular strength is more important thanfine control and another motor unit where fine control ismore important?arrow_forward
- Explain how a slight (but smooth) contraction differs from a vigorous contraction of the same muscle. Use the concepts of multiple motor unit summation.arrow_forwardWhat is the correlation of the motor end plate with the skeletal muscles? Explain.arrow_forwardWhat might happen if you could suddenly stimulate gamma motor neurons to leg flexor muscles in a resting position?arrow_forward
- How would you explain the following observation? When motor nerve fibers in the leg are severed, the muscles they innervate become paralyzed; however, in time, control over the muscles often returns.arrow_forwardEvery skeletal muscle fiber is supplied by a motorneuron at the NMJ. Watch this video(http://openstaxcollege.org/l/skelmuscfiber) to learnmore about what happens at the neuromuscular junction. (a) What is the definition of a motor unit? (b) What is thestructural and functional difference between a large motorunit and a small motor unit? Can you give an exampleof each? (c) Why is the neurotransmitter acetylcholinedegraded after binding to its receptor?arrow_forwardGiven what you have learned from the first experiment, you prepare the other leg for a fresh experiment. When you add acetylcholine to the preparation, the muscle contracts. You add curare, and again add acetylcholine to the preparation, and the muscle does not contract. Based on these data, and the data from the first experiment, this means curare is potentially acting on: Both the alpha motor neurons' ability to conduct action potentials, and the muscle's ability to conduct action potentials, but not on the neuromuscular junction. O Both the alpha motor neurons' ability to conduct action potentials, and the neuromuscular junction, but not the muscle's ability to conduct action potentials. O Both the neuromuscular junction and the muscle's ability to conduct action potentials, but not on the alpha motor neurons' ability to conduct action potentials. O It must only be affecting the muscle's ability to conduct action potentials. O It must only be affecting the neuromuscular junction. O…arrow_forward
- A nerve fiber,together with all of the muscle fibers it innervates, is called amotor unit. A motor unit obeys the all-or-none law. Why?arrow_forwardBriefly explain the muscle system why is it important and what do you find interesting?arrow_forwardThe fast fatigable motor units are used predominantly for which of the following activities? a.Sleeping. b.Jumping. c.Walking. d.Sitting. e. Standing.arrow_forward
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