Textbook Question
The velocity of nerve impulse conduction is greatest in
a. Heavily myelinated, large-diameter fibers
b. Myelinated, small-diameter fibers
c. Nonmyelinated, small-diameter fibers
d. Nonmyelinated, large-diameter fibers
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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 18
Hoehn, Haynes, Abbott 12th EditionCh. 11 Fundamentals of the Nervous System and Nervous TissueProblem 18Chapter 11, Problem 18
What is the polarized membrane state? How is it maintained? (Note the relative roles of both passive and active mechanisms.)
Verified step by step guidance1
Understand that the polarized membrane state refers to the difference in electrical charge across the plasma membrane of a cell, typically a neuron or muscle cell, where the inside of the cell is more negative relative to the outside.
Recognize that this polarization is primarily due to the unequal distribution of ions, especially sodium (Na\^+), potassium (K\^+), chloride (Cl\^-), and negatively charged proteins, across the membrane.
Identify the passive mechanisms that contribute to maintaining polarization, such as the selective permeability of the membrane to ions (mainly K\^+ leaking out of the cell) and the diffusion of ions down their concentration gradients through ion channels.
Explain the active mechanism, which is the sodium-potassium pump (Na\^+/K\^+ ATPase), that uses ATP energy to actively transport 3 Na\^+ ions out of the cell and 2 K\^+ ions into the cell, against their concentration gradients, helping to maintain the resting membrane potential.
Summarize that the polarized state is maintained by a balance between passive ion movement (diffusion and leakage) and active transport (Na\^+/K\^+ pump), which together establish and preserve the resting membrane potential essential for cell excitability.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Polarized Membrane State
The polarized membrane state refers to the difference in electrical charge across a cell's plasma membrane, typically with the inside being more negative relative to the outside. This resting membrane potential is essential for functions like nerve impulse transmission and muscle contraction.
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Guided course
04:15
Characteristic 1: Polarity
Passive Mechanisms in Membrane Polarization
Passive mechanisms involve the movement of ions down their electrochemical gradients through ion channels, such as potassium ions leaking out of the cell. These movements help establish and maintain the resting membrane potential without energy expenditure.
Recommended video:
05:05Passive vs. Active Transport
Active Mechanisms in Membrane Polarization
Active mechanisms use energy, primarily from ATP, to transport ions against their concentration gradients via pumps like the sodium-potassium ATPase. This pump moves sodium out and potassium into the cell, crucially maintaining ion gradients that sustain the polarized state.
Recommended video:
02:37Active Transport
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
a. Describe the composition and function of the cell body.
b. How are axons and dendrites alike? In what ways (structurally and functionally) do they differ?
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Textbook Question
The effects of neurotransmitter binding are very brief. Explain.
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Textbook Question
a. Contrast unipolar, bipolar, and multipolar neurons structurally.
b. Indicate where each is most likely to be found.
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Textbook Question
Describe the events that must occur to generate an AP. Relate the sequence of changes in permeability to changes in the ion channels, and explain why the AP is an all-or-none phenomenon.
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