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K+ channels open Na+ channels closed

Figure 10.13

At rest (a), the membrane potential is about -70 millivolts. When the membrane reaches threshold (b), voltage-sensitive sodium channels open, some Na+ diffuses inward, and the membrane is depolarized. Soon afterward (c), voltage-sensitive potassium channels open, K+ diffuses out, and the membrane is repolarized. (Negative ions not shown.)

stimulation at the motor end plate triggers an impulse to travel over the surface of the fiber and down into its transverse tubules. See table 10.3 for a summary of the events leading to the conduction of a nerve impulse.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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