Animations: The Nervous System

NSCI/280 Version 5

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University of Phoenix Material

Animations: The Nervous System

Action Potential Generation

After viewing the animation, answer these questions:

1. When the cell membrane is at its resting membrane potential, in what position are the voltage-gated sodium and potassium channels?

2. is initiated by a stimulus that makes the membrane .

3. What affect does this have on the voltage-gated sodium channels? What occurs at threshold?

4. What causes depolarization? What happens to the voltage-gated potassium channels?

5. Therefore, depolarization occurs because .

6. What causes the diffusion of sodium ions to decrease? What happens to the potassium ions?

7. What causes the membrane potential to become slightly more negative than the resting value?

8. What causes reestablishment of resting membrane potential?

Action Potential Propagation

After viewing the animation, answer these questions:

1. An action potential is propagated .

2. During an action potential, the inside of the cell membrane .

3. What happens to the membrane immediately adjacent to the action potential?

4. What occurs when depolarization caused by the local currents reaches threshold?

5. Why does action potential propagation occur in only one direction?

Chemical Synapse

After viewing the animation, answer these questions:

1. What is caused by action potentials arriving at the presynaptic terminal?

2. What occurs when calcium ions diffuse into the cell?

3. What do the acetylcholine molecules do? What does this cause?

4. If the membrane potential reaches threshold level, .

Typical Spinal Nerve

After viewing the animation, answer these questions:

1. How many spinal nerves exist for each vertebral level?

2. What structures connect each spinal nerve to the spinal cord?

3. What structure is made up of bundles of nerve fibers carrying sensory information from the skin to the spinal cord?

4. Where are the cell bodies (somas) of these sensory nerve fibers located?

5. Name the structure consisting of bundles of motor (efferent) fibers carrying impulses away from the spinal cord to the skeletal muscles.

6. Where are the cell bodies (somas) associated with these nerve fibers located?

7. What structures unite to form the spinal nerve?

8. The spinal nerves exit the vertebral column through what structure?

9. What is a mixed nerve?

10. Name the two branches that form from each spinal nerve.

11. What structures innervate the muscles and skin of the back?

12. What structures innervate the muscles and skin of the lateral and ventral trunk and the limbs?

Reference

Broyles, R. B. (2012). Workbook to accompany anatomy & physiology revealed version 3.0. New York, NY: McGraw-Hill.