CHAPTER 7a: NERVOUS SYSTEM

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CHAPTER 7a NERVOUS SYSTEM
Nervous system master control and communication
Three functions
1. Gathering Sensory input (information about
stimuli).

1. Integration (interpretation and decision-making
   about the stimuli).

!
3. Effects a response motor output.
RUN AWAY!
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Organization of the Nervous System
Structural Classification CNScentral nervous
systemincludes brain and spinal
cord PNSperipheral nervous systemincludes
nerves
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Organization of the Nervous System
Functional Classification Afferent/Sensory
Divisionconveys impulses to the
CNS Efferent/Motor Divisionconveys impulses
from the CNS Subdivisions
Somatic/Voluntary NS Autonomic/Involuntary NS
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Nervous Tissue
Supporting Cells pg 197 Fig 7.3 Supporting the
CNS Neuroglia/Glia nerve glue cells
Astrocytes 50 of nerve tissue protect neurons
from harmful substances in blood
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Nervous Tissue

• 2. Microglial Cells
• phagocytes (dispose of
• debris like dead brain cells,
• bacteria, etc.)
• Ependymal Cells
• line brain and spinal cord cavities to circulate
  cerebrospinal fluid

Flash Cerebrospinal Fluid Circulation
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Nervous Tissue

• Oligodendrocytes produce myelin sheaths
  (coverings that protect the nerves) for CNS
  nerves

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Nervous Tissue

• Supporting Cells of PNS
• Schwann Cells
• form myelin sheaths around nerves in PNS

Myelin sheath (blue)
No Myelin sheath
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Nervous Tissue

• Supporting Cells of PNS
• Satellite Cells
• protection, cushioning

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Anatomy of a Nerve Cell
Myelin Sheath
Node of Ranvier
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Anatomy of a Nerve Cell
Dendrites conduct impulses toward the cell body.
Axons conduct impulses away from the cell body.
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Anatomy of a Nerve Cell
Flash Shingles
Myelin Sheaths and Shingles
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Anatomy of a Nerve Cell
CNS clusters of nerve cells nuclei PNS clusters
of nerve cells ganglia
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Anatomy of a Nerve Cell
Tracts bundles of nerves in CNS Nerves
bundles of nerves in the PNS
spiltmartini.com
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Anatomy of a Nerve Cell
Types of Sensory Receptors 1. Naked Nerve
Endings pain temperature
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Anatomy of a Nerve Cell
Types of Sensory Receptors 2. Meissners
corpuscles touch
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Anatomy of a Nerve Cell
Types of Sensory Receptors 3. Pacinian
corpuscle deep pressure
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Anatomy of a Nerve Cell

• Types of Sensory Receptors
• Proprioceptors
• muscular stretching or tension

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Anatomy of a Nerve Cell
White matter myelinated regions of the
brain Gray matter unmyelinated regions of the
brain
Flash The Human Brain How We Decide
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Anatomy of a Nerve Cell
White matter and gray matter in MRI scans
http//player.discoveryeducation.com/index.cfm?gui
dAssetIdB1721030-D95E-45BF-B764-D4AC4026D0C0blnF
romSearch1productcodeUS
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The Nerve Impulse

• Major functional properties
• Irritability
• ability to respond to stimuli

I am irritable! AndYou are getting on my very
last nerve!
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The Nerve Impulse
Conductivity ability to conduct electrical
currents

• Resting membrane
• Na and K levels are equal

Na
Na
Na
Na
Na
Na
K
K
K
K
K
K
Nerve impulses are all-or-nothing events.
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Conductivity
The Nerve Impulse
B. Depolarization starts Na moves into nerve
cell. Cell depolarizes (becomes too inside)
Action Potential is generated.
Na
Na
Na
Na
Na
Na
Depolarization
K
K
K
K
K
K
K
ACTION POTENTIAL
De reversal
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Conductivity
The Nerve Impulse
C. Action potential is propagated.
Na
Na
Na
Na
Na
Na
Depolarization
K
K
K
K
K
K
K
K
K
K
K
K
K
ACTION POTENTIAL
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Conductivity
The Nerve Impulse
C. REpolarization.
Re again
REpolarization
K
K
K
K
K
K
Na
Na
Na
Na
Na
Na
Too much inside!
Back to equal!
Nerve Impulse http//highered.mcgraw-hill.com/site
s/0072495855/student_view0/chapter14/animation__th
e_nerve_impulse.html
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Nerve to Nerve
Flash Neurotransmitter_Synapse_3D_Animation
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Reflexes
Auto self
Reflex rapid, predictable, involuntary
response Reflex Arc neural pathway of a reflex
(goes only one way)
Autonomic reflexes regulate smooth muscles
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Reflexes
Soma body
http//www.sumanasinc.com/webcontent/animations/co
ntent/reflexarcs2.html
Somatic reflexes stimulates skeletal muscles
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Brain Stem
About the size of a thumb in diameter and about 3
inches long.
rainbowrehab.com
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Brain Stem
Midbrain small part that relays impulses and
controls reflexes for vision and hearing.
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Brain Stem
Pons bridge
Pons rounded structure of mostly fiber tracts
involved in the control of breathing.
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Brain Stem
Medula Oblongata merges into spinal cord
regulates vital internal activities including
heart rate, blood pressure, breathing,
swallowing, vomiting, etc.
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Brain Stem
Cerebellum Outer gray matter inner white
matter. Provides timing for skeletal muscle
activity, controls balance, and equilibrium.
Compared to autopilot because it constantly
checks and adjusts.
Ataxia Clumsy and disorganized movements as a
result of damage to the cerebellum.
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THE CNS
The BRAIN
Brain pg 207 Fig 7.13c and pg 209 Fig 7.15.
Brain Function and Anatomy http//www.waiting.com/
brainfunction.html Go to the website and take
notes including identification of the sections of
the brain, what it normally does, and what may
happen if that section is damaged.
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Brain Explorer An interactive resource for
knowledge about the human brain. http//www.brain
explorer.org/brain_atlas/brainatlas_index.shtml
Bon Voyage! Go Explore the Brain.
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BRAIN FUN! RIGHT BRAIN VS LEFT BRAIN
http//www.wherecreativitygoestoschool.com/vancouv
er/left_right/rb_test.htm
http//homeworktips.about.com/library/brainquiz/bl
_leftrightbrain_quiz.htm
http//similarminds.com/brain.html
http//frank.mtsu.edu/studskl/hd/learn.html
What are your results? Are you right or left
brained? What does it mean?
http//frank.mtsu.edu/studskl/hd/learn.html