1. PowerPoint Lecture Outlines to accompany
Hole’s Human
Anatomy and Physiology
Tenth Edition
Shier w Butler w Lewis
Chapter 10
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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2. Chapter 10 Nervous System I
Purpose -
To generates and conducts electrical impulses
!!! Coordinates all body systems by !!! electrochemical current
The structural and functional unit of the nervous system is a NEURON (nerve cell)

3. Functions of Nervous System
Sensory Function
sensory receptors gather information
information is carried to the Central Nervous System (CNS)
Motor Function
decisions are acted upon
impulses are carried to effectors through the Peripheral Nervous System (PNS)
Integrative Function
sensory information used to create
sensations
memory
thoughts
decisions
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4. Two Major Systems of the Nervous System
1. Central Nervous System (CNS)
brain
spinal cord
2. Peripheral Nervous System (PNS)
peripheral nerves (43 nerves)
cranial nerves (12 pair)
spinal nerves (31 Pair)
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5. Two Divisions of Nervous System
Sensory Division
INPUT INTO CNS (afferent neurons)
picks up sensory information and delivers
it to the CNS.
2. Motor Division (made up of two divisions)
OUTPUT FROM CNS to PNS (efferent neurons)
carries information to muscles and glands
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6. Two Division of the Motor Division
1.Somatic – carries information to skeletal muscle. 2. Autonomic (made up of two divisions) – carries information to smooth muscle, cardiac muscle, and glands

7. Two Divisions of the Autonomic Division
PARASYMPATHETIC
Usually promotes those activities associated with a normal state.
HOMEOSTASIS!!!
SYMPATHETIC
Effects are generally associated with emergency situations
FIGHT OR FLIGHT!!!

8. Divisions Nervous System
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9. Histology of Nervous Tissue
Two principal cell types
Neurons—excitable cells that transmit electrical signals
Neuroglia (glial cells)—supporting cells:
Astrocytes (CNS)
Microglia (CNS)
Ependymal cells (CNS)
Oligodendrocytes (CNS)
Satellite cells (PNS)
Schwann cells (PNS)

10. Histology of Nervous Tissue
Neuroglia (glial cells)—supporting cells:
Astrocytes (CNS)
Microglia (CNS)
Ependymal cells (CNS)
Oligodendrocytes (CNS)
Satellite cells (PNS)
Schwann cells (PNS)

11. Neuron Structure
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12. Types of Neurons Bipolar two processes eyes, ears, nose Unipolar
one process
ganglia
Multipolar
many processes
most neurons of CNS
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13. Classification of Neurons
Sensory Neurons
afferent
carry impulse to CNS
most are unipolar
some are bipolar
Interneurons
link neurons
multipolar
in CNS
Motor Neurons
multipolar
carry impulses away from CNS
carry impulses to effectors
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14. STOP HERE!!!!

15. Types of Neuroglial Cells
Schwann Cells
peripheral nervous system
myelinating cell
Astrocytes
CNS
scar tissue
mop up excess ions, etc
induce synapse formation
connect neurons to blood vessels
Oligodendrocytes
CNS
myelinating cell
Ependyma
CNS
ciliated
line central canal of spinal cord
line ventricles of brain
Microglia
CNS
phagocytic cell
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16. Types of Neuroglial Cells
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17. Regeneration of A Nerve Axon
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18. Resting Membrane Potential
inside is negative relative to the outside
polarized membrane
due to distribution of ions
Na+/K+ pump
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19. Potential Changes at rest membrane is polarized
threshold stimulus reached
sodium channels open and membrane depolarizes
potassium leaves cytoplasm and membrane repolarizes
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20. Local Potential Changes
occur on membranes of dendrites and cell bodies
caused by various stimuli
chemicals
temperature changes
mechanical forces
if membrane potential becomes more negative, it has hyperpolarized
if membrane potential becomes more positive, it has depolarized
graded
summation can lead to threshold stimulus that starts an action potential
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21. Action Potentials nerve impulse occur on axons all-or-none
refractory period
absolute - time when threshold stimulus does not start another action potential
relative – time when stronger threshold stimulus can start another action potential
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22. Nerve Impulse (NI)
The transmission of an action potential along a neuron.
NI is an electrical impulse.
This is similar to a row of dominos (one falls, they all fall)
NI begins on a dendrite run towards the cell body, through the cell body, and then down the axon

23. Action Potentials
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24. Impulse Conduction
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25. Impulse Conduction The manner in which the NI runs down the neuron.
Unmyelinated Neurons – NI must travel the length of the neuron.
Myelinate Neurons – Jump from Node of Ranvier to Node of Ranvier.
SALTATORY CONDUCTION!!!
*VERY FAST TRANSMISSION*

26. Saltatory Conduction
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27. The Synapse Nerve impulses pass from neuron to neuron at:
Synapses – the junction between two neurons where a nerve impulse is transmitted
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28. Synaptic Cleft
Occurs between the axon of one neuron and the dendrite of a second neuron.
NOTE!!!
The two neurons DO NOT TOUCH!!!
This is called the synaptic cleft
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29. Synaptic Potentials EPSP excitatory postsynaptic potential graded
depolarizes membrane of postsynaptic neuron
action potential of postsynaptic neuron becomes more likely
IPSP
inhibitory postsynaptic potential
graded
hyperpolarizes membrane of postsynaptic neuron
action potential of postsynaptic neuron becomes less likely
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30. Summation of EPSPs and IPSPs
EPSPs and IPSPs are added together in a process called summation
More EPSPs lead to greater probability of action potential
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31. Neurotransmitters
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32. Impulse Processing Neuronal Pools
groups of interneurons that make synaptic connections with each other
interneurons work together to perform a common function
each pool receives input from other neurons
each pool generates output to other neurons
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33. Convergence neuron receives input from several neurons
incoming impulses represent information from different types of sensory receptors
allows nervous system to collect, process, and respond to information
makes it possible for a neuron to sum impulses from different sources
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34. Divergence one neuron sends impulses to several neurons
can amplify an impulse
impulse from a single neuron in CNS may be amplified to activate enough motor units needed for muscle contraction
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35. Clinical Application Multiple Sclerosis Causes Symptoms
myelin destroyed in various parts of CNS
hard scars (scleroses) form
nerve impulses blocked
muscles do not receive innervation
may be related to a virus
Symptoms
blurred vision
numb legs or arms
can lead to paralysis
Treatments
no cure
bone marrow transplant
interferon (anti-viral drug)
hormones
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