The Nervous System
Chapter 9
Learning Objectives:
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Describe the structure and function of neurons and neuroglia
Differentiate between white matter and gray matter
Describe the function of afferent and efferent nerves
List the components of the central nervous system and the peripheral nervous system
Differentiate between the autonomic and somatic nervous system
Describe the process of depolarization and repolarization of neurons (action potential)
Identify the structures of the synapse and explain their functions
Understand excitatory and inhibitory neurotransmitters and describe their role in the conduction of
nerve impulses
Describe the structure and function of the cerebrum, cerebellum, diencephalon, and brainstem
Describe the connective tissue layer that surrounds the brain and spinal cord
Explain the functions of cerebrospinal fluid
List the cranial nerves and describe their function
Differentiate between the sympathetic and parasympathetic divisions of the autonomic nervous system
Differentiate between autonomic and somatic reflexes
Describe the components of the reflex arc
Describe the stretch reflex, withdrawal reflex, crossed extensor reflex, palpebral reflex, and pupillary
light reflex
Introduction to the
Nervous System
Major Functions:
� Control
� Coordinate
� Communicate
How does it do these things?
� Signal reception
� Signal integration
� Signal transmission
Neurons and
Supporting Cells
The Neuron Figure 9-1, Page 229
Neuroglia
Organizational Schemes of
the Nervous System
� Anatomic location
� Direction of impulse transmission
� Function
Anatomic Location
Direction of Impulse Transmission
Function
Organization of the Nervous System Overview
Neuron
Function:
The Action
Potential
Overview: The Action Potential
Resting State- Sodium Potassium Pump creates electrochemical gradient
Depolarization- Sodium gates open
Repolarization- Potassium gates open
Sodium- Potassium Pump brings back to Resting State
SodiumPotassium
Pump
The Action
Potential
Figure 9-5, Page 233
All or Nothing Principle
Saltatory Conduction
How Neurons Communicate: The
Synapse
The Synapse
Figure 9-7, Page 336
National Geographic: Mapping the Brain (Synapse)
Neurotransmitters
Types of Neurotransmitters
● Excitatory- Depolarize
○ Cause postsynaptic membrane to become more positive
with the influx of sodium
● Inhibitory- Hyperpolarize
○ Cause the postsynaptic membrane to become more
negative with the influx of chloride or outflux of potassium
Specific Neurotransmitters
Acetylcholine- excitatory (somatic)
and inhibitory
(parasympathetic)
Catecholamines
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Norepinephrine- excitatory in fight or flight
Epinephrine- excitatory in fight or flight
Dopamine- excitatory and inhibitory in brain
Gamma-aminobutyric acid (GABA) and
Glycine- inhibitory in brain and spinal cord (tranquilizers)
Neurotransmitter Recycling
The Central Nervous System
Central Nervous System (Figure 9-8, Page 239)
Meninges
Figure 9-10, Page 240
Cerebrospinal Fluid
Blood Brain Barrier
Cranial Nerves
Table 9-1, Page 243
Know name, number and key functions of all.
Spinal
Cord
Figure 9-11, Page 244
The Autonomic Nervous System
Structure of the
Autonomic System
Figure 9-12,
Page 245
Sympathetic
System
Parasympathetic
System
Functions of the Sympathetic and Parasympathetic Nervous System Table 9-3, Page 246
Sympathetic
Parasympathetic
Heart rate
Increases
Decreases
Force of heart contraction
Increases
Decreases
Diameter of bronchioles
Dilates
Contricts
Diameter of pupil
Dilates
Constricts
Gastrointestinal function
Decreases
Increases
Diameter of skin and kidney blood
vessels
Decreases
No significant effect
Diameter of muscle blood vessels
Increases
Decreases
Neurotransmitters at the Postganglionic
Receptor,
Figure 9-13, Page 247
Neurotransmitter
Use in the
Parasympathetic
and Sympathetic
Nervous Systems
Reflexes and Reflex Arcs
Stretch Reflex, Figure 9-14, Page 248
Withdrawal Reflex, Figure 9-15, Page 249
Crossed Extensor Reflex, Figure 9-16, Page 250
Palpebral reflex and Pupillary light reflex
Clinical Neurology
and Functional
Neuroanatomy from
University of Georgia