REVIEW NEURONS AND THEIR FUNCTIONS
01/07/2007 08:44 PM
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CHAPTER 49, PART 1
THE NERVOUS SYSTEM
REVIEW NEURONS AND THEIR FUNCTIONS
CHAPTER 50, PART 1, THE NERVOUS SYSTEM NOTES
1. The cells that carry messages throughout the nervous system are called
____________________________________________.
2. The nervous system ______________________________ and _________________________ information
about activities within the body and monitors and responds to ____________________________ and
__________________________ changes.
3. The nervous system ________________________ and ________________________ all essential functions
of the human body.
4. Neurons that carry impulses from the sense organs to the brain and spinal cord are called
____________________________________________ neurons.
5. A _________________________________ is the basic functional unit of the nervous system.
6. The ________________________________________ is the largest part of a neuron, and consist of the
nucleus and much of the cytoplasm.
7. Neurons that carry impulses from the brain and spinal cord to muscles or glands are called
_____________________________________________________ neurons.
8. The _________________________________ carry impulses toward the cell body.
9. Messages take the form of electrical signals, and are known as
_______________________________________________________________________.
10. A neuron may have dozens or even hundreds of _________________________________ but usually only
one __________________________________.
11. A nerve impulse is a flow of electrical charges along the __________________________
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___________________________________ of a neuron.
12. What ions are moved across a neuron giving it its electric potential?
_______________________________________ and ____________________________________
13. A Neuron consists of Three Main Parts, List Them:
A.__________________________________________________
B.__________________________________________________
C.__________________________________________________
14. The electrical potential is due to proteins in the neuron known as _____________________
________________________________________________________________________.
15. Myelin is produced by _________________________________ cells, which surround the
____________________________ of a neuron.
16. The depolarization and repolarization of a neuron membrane is called a(n)
________________________________ _______________________________.
17. The _________________________________ carry impulses away from the cell body.
18. What are the spaces between adjacent neurons called? _________________________
________________________________________________
19. A change in the environment that may be of sufficient strength to initiate an impulse is called a(an)
____________________________________________________.
20. The minimum level of a stimulus that is required to activate a neuron is called the
___________________________________________________________.
21. What are two major divisions of the nervous system?
1.___________________________________________________________________
2.___________________________________________________________________
22. For a neuron to achieve resting potential, it must move _____________________________ ions out of the
cell, and actively pump _____________________________ ions into the cell.
23. _________________________ neurons carry impulses from receptors to the spinal cord and brain.
24. _________________________ neurons carry impulses from the spinal cord to the effectors.
25. Within the spinal cord, motor and sensory neurons are connected by
_______________________________________________________________.
26. At the beginning of an impulse, the ____________________________________ gates open.
27. A ___________________________ is the basic unit of communication of the nervous system.
28. Cytoplasmic extensions called ________________________ allow a neuron to receive information
simultaneously from many different sources.
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29. Destruction of large patches of myelin sheath can result is a disease known as
_________________________ __________________________________. (MS)
30. Some axons are surrounded by an insulating structure called a ____________________________
____________________________________.
31. A neuron transmits a nerve impulse as a wave of ______________________________________________
or ___________________________ ____________________________.
32. Messages are carried across synapses by _________________________________________________.
33. The junction of a neuron with another neuron or muscle cell is called a
_________________________________.
33. The junction of a neuron with a muscle cell is called a _________________________________
__________________________________.
For questions 1-6 below, match the following answers to one of the statements below.
A. Depolarization
B. Sodium-potassium pump
C. Action Potential
____ 1.
____ 2.
____ 3.
____ 4.
____ 5.
____ 6.
D. Resting Potential
E. Refractory Period
F. Repolarization
Charges inside the axon change positive.
Active transport system.
Axon is not conducting an impulse.
Time when the axon cannot conduct an impulse.
Axon is depolarized, then repolarized.
K+ moves out of the axon
DIRECTIONS: Answer the questions below as completely and as thoroughly as possible. Answer the
question in essay
form (not outline form), using complete sentences. You may use diagrams or pictures to supplement your
answers, but a diagram or picture alone without appropriate discussion is inadequate. See me if you need Help,
Have Problems or Questions or To Check Your Answers.
1. Explain the difference between an afferent neuron and an efferent neuron.
2. List the Functions of the Nervous System.
3. Describe the role of neurotransmitters in transmitting a signal across a synaptic cleft.
4. Describe the process of the nerve impulse from the point at which the nerve has been stimulated.
5. How is the signal in the nervous system transmitted between adjacent neurons?
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6. Describe the structure of a neuron.
7. What functional advantage does a neuron with several dendrites have over a neuron with only one dendrite?
8. Briefly explain how the relative concentrations of sodium ions and potassium ions inside and outside
a neuron change during an action potential.
9. Distinguish between sensory receptors, motor neurons, and interneurons.
10. What role does the sodium-potassium pump play in the restoration of the membrane potential?
11. Contrast resting potential with action potential.
12. Explain the importance of the refractory period and what occurs during the refractory period.
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