Textbook Question
Rochelle developed multiple sclerosis when she was 27. After eight years she had lost a good portion of her ability to control her skeletal muscles. How did this happen?
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Ch. 11 Fundamentals of the Nervous System and Nervous Tissue
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732
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Table of contents
- Ch. 1 The Human Body: An Orientation25
- Ch. 2 Chemistry Comes Alive24
- Ch. 3 Cells: The Living Units24
- Ch. 4 Tissue: The Living Fabric19
- Ch. 5 The Integumentary System12
- Ch. 6 Bones and Skeletal Tissues19
- Ch. 7 The Skeleton14
- Ch. 8 Joints7
- Ch. 9 Muscles and Muscle Tissue26
- Ch. 10 The Muscular System25
- Ch. 11 Fundamentals of the Nervous System and Nervous Tissue23
- Ch. 12 The Central Nervous System25
- Ch. 13 The Peripheral Nervous System and Reflex Activity30
- Ch. 14 The Autonomic Nervous System16
- Ch. 15 The Special Senses26
- Ch. 16 The Endocrine System26
- Ch. 17 Blood27
- Ch. 18 The Cardiovascular System: The Heart25
- Ch. 19 The Cardiovascular System: Blood Vessels27
- Ch. 20 The Lymphatic System and Lymphoid Organs and Tissues16
- Ch. 21 The Immune System: Innate and Adaptive Body Defenses27
- Ch. 22 The Respiratory System21
- Ch. 23 The Digestive System31
- Ch. 24 Nutrition, Metabolism, and Energy Balance26
- Ch. 25 The Urinary System26
- Ch. 26 Fluid, Electrolyte, and Acid-Base Balance24
- Ch. 27 The Reproductive System24
- Ch. 28 Pregnancy and Human Development25
- Ch. 29 Heredity11
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732Not the one you use?Change textbook
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Hoehn, Haynes, Abbott 12th EditionCh. 11 Fundamentals of the Nervous System and Nervous TissueProblem 25
Hoehn, Haynes, Abbott 12th EditionCh. 11 Fundamentals of the Nervous System and Nervous TissueProblem 25Chapter 11, Problem 25
Local anesthetics block voltage-gated Na⁺ channels. General anesthetics are thought to activate chemically gated Cl⁻ channels, thereby rendering the nervous system quiescent while surgery is performed. What specific process do anesthetics impair, and how does this interfere with nerve impulse transmission?
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Identify the specific process anesthetics impair: Both local and general anesthetics interfere with the generation and propagation of action potentials in neurons.
Understand how local anesthetics work: They block voltage-gated Na⁺ channels, preventing sodium ions from entering the neuron during depolarization, which stops the initiation and propagation of action potentials.
Understand how general anesthetics work: They activate chemically gated Cl⁻ channels, increasing chloride ion influx, which hyperpolarizes the neuron, making it less likely to reach the threshold needed to trigger an action potential.
Explain how these actions interfere with nerve impulse transmission: By preventing depolarization (local anesthetics) or by causing hyperpolarization (general anesthetics), the neurons cannot generate or propagate action potentials effectively, leading to a loss of sensation or consciousness.
Summarize the overall effect: Anesthetics impair the electrical excitability of neurons, thereby blocking the transmission of nerve impulses necessary for sensation and response during surgery.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Voltage-Gated Sodium Channels and Action Potential
Voltage-gated sodium channels open in response to membrane depolarization, allowing Na⁺ ions to enter the neuron. This influx initiates the rising phase of the action potential, which is essential for nerve impulse propagation along axons.
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Action Potential
Chemically Gated Chloride Channels and Inhibition
Chemically gated chloride channels open in response to neurotransmitters like GABA, allowing Cl⁻ ions to enter the neuron. This influx hyperpolarizes the membrane, making it less likely to fire an action potential, thus inhibiting nerve activity.
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Impairment of Nerve Impulse Transmission by Anesthetics
Local anesthetics block voltage-gated Na⁺ channels, preventing action potential initiation, while general anesthetics activate Cl⁻ channels, hyperpolarizing neurons. Both actions disrupt the generation and propagation of nerve impulses, leading to loss of sensation or consciousness.
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Related Practice
Textbook Question
When admitted to the emergency room, Sean was holding his right hand, which had a deep puncture hole in its palm. He explained that he had fallen on a nail while exploring a barn. Sean was given an antitetanus shot to prevent neural complications. Tetanus bacteria fester in deep, dark wounds, but how do their toxins travel in neural tissue?
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Textbook Question
The effects of neurotransmitter binding are very brief. Explain.
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Textbook Question
In the Netherlands a young man named Jan was admitted to the emergency room. He and his friends had been to a rave. His friends say he started twitching and having muscle spasms which progressed until he was 'stiff as a board.' On examination, staff found a marked increase in muscle tone and hyperreflexia involving facial and limb muscles. In his pocket, he had unmarked dark yellow tablets with dark flecks. Analysis of the tablets showed them to contain a mixture of ecstasy and strychnine. Ecstasy would not cause this clinical picture, but strychnine, which blocks glycine receptors, could. Explain how.
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Textbook Question
Explain both the anatomical and functional divisions of the nervous system. Include the subdivisions of each.
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