Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

11. Nervous Tissue and Nervous System

Change in Membrane Potential

Anatomy & Physiology

11. Nervous Tissue and Nervous System

Change in Membrane Potential

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Multiple Choice

During the action potential, when does sodium permeability initially decrease?

During the resting membrane potential

During the absolute refractory period

At the peak of the action potential

At the onset of depolarization

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Verified step by step guidance

Understand the concept of an action potential: An action potential is a rapid electrical signal that travels along the membrane of a neuron or muscle cell. It involves changes in the permeability of the membrane to sodium (Na⁺) and potassium (K⁺) ions.

Review the phases of an action potential: The key phases are resting membrane potential, depolarization, peak of the action potential, repolarization, and hyperpolarization. Each phase is associated with specific changes in ion permeability.

Focus on sodium permeability: During depolarization, voltage-gated sodium channels open, causing a rapid influx of Na⁺ ions into the cell, which increases sodium permeability. This continues until the peak of the action potential.

Identify when sodium permeability decreases: At the peak of the action potential, voltage-gated sodium channels begin to inactivate, reducing sodium permeability. This marks the transition from depolarization to repolarization.

Relate this to the options provided: Sodium permeability does not decrease during the resting membrane potential or the onset of depolarization. It decreases specifically at the peak of the action potential, which is the correct answer.