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Chapter 12
NERVOUS TISSUE
Outline and Objectives
INTRODUCTION
1. Compare the nervous system and endocrine system in maintaining
homeostasis.
OVERVIEW OF THE NERVOUS SYSTEM
Structures and Functions of the Nervous System
2. Identify the structures that make up the nervous system.
3. List and explain the three basic functions of the nervous system.
4. Classify the organs of the nervous system into central and peripheral divisions
and their subdivisions, and indicate the paths of afferent and efferent
information.
HISTOLOGY OF NERVOUS TISSUE
5. Contrast the general functions of neuroglia and neurons.
Neurons
6. Discuss the property of electrical excitability in regards to neurons.
Parts of a Neuron
7. Describe the internal and external structures of the neuron and their functions.
8. Characterize the two means of axonal transport and their use.
9. Discuss the disease tetanus in regards to axonal transport systems.
Structural and Functional Variation in Neurons
10. Identify neurons on the basis of their structural and functional classifications.
Neuroglia
11. Describe the functions and relative number of neuroglia compared to neurons.
12. Describe the different forms, locations, and purposes of the four types of
neuroglia.
Myelination
13. Iden4tify the cells that produce myelin, describe how the sheath is formed,
and discuss its function.
Gray and White Matter
14. Describe the difference between gray and white matter, and give examples of
each.
ELECTRICAL SIGNALS IN NEURONS
15. Distinguish between action potential and graded potentials.
Ion Channels
16. Identify the basic types of ion channels and the stimuli that operate gated ion
channels.
Resting Membrane Potentials
17. Describe the ions, channels, and integral-protein pumps that contribute to
generation of a resting membrane potential.
Graded Potentials
18. Discuss the features of the graded potential including areas where generated,
size, properties, and type.
Action Potential
19. List the sequence of events involved in generation of a nerve impulse.
20. Explain why an initial threshold voltage necessitates a complete subsequent
sequence of events that produces the set voltage changes of an action
potential.
Depolarizing Phase
21. Describe the events involved in depolarization of the nerve cell membrane.
Repolarizing Phase
22. Describe the repolarization of the nerve cell membrane.
Refractory Period
23. Compare the absolute and relative refractory periods and the relation of axon
diameter to action potential generation frequency.
Propagation of Action Potentials
24. Discuss how the sodium ion flow in one area of an axon leads to initiation of
an action potential in an adjacent region of the axon membrane.
25. Discuss the use of local anesthetics to block pain and other somatic
sensations.
Continuous and Saltatory Conduction
26. Compare and contrast continuous and saltatory conduction.
Speed of impulse Propagation
27. Outline the physical and cellular factors and how they alter the rate of action
potential propagation along an axon.
Encoding of Stimulus Intensity
28. Note the two means through which strength of stimulus is conveyed to the
brain even though all action potentials are the same size.
Comparison of Electrical Signals Produced by Excitable Cells
29. Describe the differences in magnitude and timing between nerve and various
muscle action potentials.
SIGNAL TRANSMISSION AT SYNAPSES
30. Explain the events of synaptic transmission.
Electrical Synapses
31. Describe the properties of an electrical synapse, the way impulses are
transmitted, and the advantages of an electrical synapse.
Chemical Synapse
32. Define the anatomic, chemical, enzymatic, and receptor components of a
chemical synapse.
33. Go through the sequence of events that allow an action potential on an axon to
be transmitted into a graded potential on a postsynaptic membrane.
Excitatory and Inhibitory Postsynaptic Potentials
34. Indicate the voltage changes associated with EPSPs and IPSPs, and how these
potentials are related to various ion channels.
Removal of Neurotransmitter
35. Note the means by which neurotransmitter concentrations in the synaptic cleft
are diminished, and the effect on impulse transmission.
Spatial and Temporal Summation of Postsynaptic Potentials
36. Distinguish between spatial and temporal summation.
37. Describe the effect the sum of the excitatory and inhibitory effects have on the
postsynaptic neuron.
38. Describe the effect of strychnine on normal inhibition.
NEUROTRANSMITTERS
39. Describe and give examples and functions of the various neurotransmitter
classes.
Small-Molecule Neurotransmitters
Acetylcholine
Amino Acids
Biogenic Amines
ATP and Other Purines
Gases
Neuropeptides
40. Discuss excitotoxicity.
CIRCUITS IN THE NERVOUS SYSTEM
41. Describe the various types of neuronal circuits in the nervous system.
REGENERATION AND REPAIR OF THE NERVOUS SYSTEM
42. Discuss the plasticity of the nervous system.
Neurogenesis in the Central Nervous System
43. Describe mechanisms that encourage neurogenesis and neuronal growth.
Damage and Repair of the Peripheral Nervous System
44. Discuss the effects of damage on the peripheral nervous system and the steps
required for repair.
DISORDERS: HOMEOSTATIC IMBALANCES
45. Discuss multiple sclerosis in terms of symptoms, anatomical changes, causes,
and treatments.
46. Discuss epilepsy in terms of symptoms, anatomical changes, causes, and
treatments.