Lecture Outline

CHAPTER OVERVIEW: The nervous system and its various roles in the maintenance of homeostasis are described. The functional divisions of the nervous system are defined. The structure and function of the types and parts of neurons and synapses are described in detail. The neural reflex arc is discussed and the function of neuronal circuits is considered.

OUTLINE (three fifty-min. lectures):

 Chapt. Object.

Topic Outline, Chapter 12

 

Figures & Tables

Trnspcy. Acetates

Trnspcy.

Masters

1

I. Divisions of the Nervous System

Fig. 12.1, p.356

TA-154

  
 

    A. Central Nervous System (CNS)
      
 

      1. Brain
      
 

      2. Spinal Cord
      
 

    B. Peripheral Nervous System (PNS)
      
 

      1. Nerves
      
 

        a. Cranial Nerves
      
 

        b. Spinal Nerves
      
 

      2. Ganglia
      
 

      3. Functional Subdivisions of the PNS

Figs. 12.2, p.356 & 12.3, p.357

TA-155

TM-28
 

        a. Afferent or Sensory
      
 

        b. Efferent or Motor
      
 

          1). Somatic Nervous System
      
 

          2). Autonomic Nervous System (ANS)

Fig. 12.3c, p.357

    
 

            a). Sympathetic Division
      
 

            b). Parasympa-thetic Division
      
         
 

II. Cells of the Nervous System

      

2

    A. Neurons

Fig. 12.4, p.358

TA-156

  
 

      1. Neuron Cell Body

Predict Quest. 1

    
 

      2. Dendrites
      
 

      3. Axons
      
 

    B. Types of Neurons
      
 

      1. Classified by Function
      
 

        a. Afferent or Sensory Neurons
      
 

        b. Efferent or Motor Neurons
      
 

        c. Association or Interneurons
      

3

      2. Classified by Structure

Fig. 12.5, p.359

  

TM-29
 

        a. Multipolar Neurons

Fig. 12.5a, p.359

    
 

        b. Bipolar Neurons

Fig. 12.5b, p.359

    
 

        c. Unipolar Neurons

Fig. 12.5c, p.359

    

4

    C. Neuroglia
      
 
      1. Astrocytes

        a. The Blood-Brain Barrier

Fig. 12.6, p.360; Clinical Note, p.360

  

TM-30
 
      2. Ependymal Cells
        a. Choroid Plexuses
        b. Cerebrospinal Fluid

Fig. 12.7a, p.360

Fig. 12.7b, p.360

  

TM-31
 
      3. Microglia

        a. Phagocytosis

Fig. 12.8, p.360; Clinical Note, p.360

  

TM-30
 
      4. Oligodendrocytes

        a. Myelin Sheaths in CNS

Fig. 12.9, p.361

TA-157

  
 

      5. Schwann Cells
      
 

        a. Neurolemmocytes (Schwann Cells) around Axons

Fig. 12.10, p.361

TA-157

  
 

        b. Satellite Cells in Ganglia

Fig. 12.11, p.362

  

TM-32

5

    D. Axon Sheaths
      
 

      1. Unmyelinated Axons

Fig. 12.12a, p.362

TA-158

  
 

      2. Myelinated Axons

Fig. 12.12b, p.362

TA-158

  
 

        a. Nodes of Ranvier
      
 

        b. Saltatory Conduction

Fig. 12.13, p.362; Predict Quest. 2; Clinical Note, p.363

TA-159

  

7

III. Organization of Nervous Tissue

      
 

    A. Central Nervous System
      

6

      1. Central White Matter = Tracts
      
 

      2. Outer Gray Matter = Cortex and Nuclei
      
 

    B. Peripheral Nervous System
      
 

      1. White Matter = Nerves

Fig. 12.14, p.363; Clinical Focus & Fig. 12-A, p.374

TA-160

TA-166

 
 

        a. Endoneurium
      
 

        b. Perineurium
      
 

        c. Nerve Fascicles
      
 

        d. Epineurium
      
 

      2. Gray Matter = Ganglia

 

      

8

IV. The Synapse

      
 

      1. Presynaptic Terminal and Synaptic Vesicles

Fig. 12.15, p.364

  

TM-33
 

      2. Mechanism of Neurotransmitter Release

Clinical Note, p.365

    
 

      3. Diffusion Across Synaptic Cleft
      
 

      4. Binding with Receptors in Postsynaptic Membrane
      
 

      5. Changes in Postsynaptic Membrane
      
 

      6. Inactivation of Neurotransmitters

Clinical Note, p.365

    

 

9

    A. Receptor Molecules in Synapses

    B. Neurotransmitters and Neuromodulators

Table 12.1, pp.366-367; Clinical Note, p.365

    

10

    C. Excitatory and Inhibitory Postsynaptic Potentials
      
 

      1. Excitatory Postsynaptic Potentials (EPSP's)

Fig. 12.16a, p.368; Clinical Note, p.367

  

TM-34
 

        a. Local Depolarization
      
 

        b. Excitatory Neurons
      
 

      2. Inhibitory Postsynaptic Potentials (IPSP's)

Fig. 12.16b, p.368

  

TM-34
 

        a. Local Hyperpolarization
     
 

        b. Inhibitory Neurons
      

11

    D. Presynaptic Inhibition and Facilitation

Fig. 12.17, p.368

TA-161

  
 

        a. Presynaptic Inhibition
      
 

        b. Presynaptic Facilitation (Glutamate and Nitric Oxide)
      

12, 13

    E. Spatial and Temporal Summation

Fig. 12.18, p.369; Predict Quest. 3

TA-162

  
 

V. Reflexes

      

14

    A. General Reflex Arc

Fig. 12.19, p.370

TA-163

  
 

      1. Sensory Receptor
      
 

      2. Afferent (Sensory) Neuron
      
 

      3. Association Neurons (in CNS)
      
 

      4. Efferent (Motor) Neuron
      
 

      5. Effector Organ
      
 

    B. Role of Reflexes in Homeostasis
      
         

15

VI. Neuronal Pathways and Circuits

Predict Quest. 4

    
 

    A. Convergent Pathways

Fig. 12.20a-b, p.371

TA-164

  
 

    B. Divergent Pathways

Fig. 12.21a-b, p.372

TA-165

  
 

    C. Oscillating Circuits

Fig. 12.22, p.373

    
 

      1. Simple
      
 

      2. Multiple Cells and Potential for After Discharge
      
         

IMPORTANT CONSIDERATIONS: The logical divisions in the material separate it into three sections: (1) the overview of the structure and cellular composition of the nervous system; (2) the activity of neurons and the functions at synapses; and (3) the functions of groups of neurons into reflex arcs which are involved in both the regulation of other organ's functions and the pathways and circuits which constitute central nervous system processing or integration of sensory and motor information.

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