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Basics of the Neuron/glia
Overview of the NS
1. neurons – 10 to 100 billion neurons
◦ Role:
-
can vary tremendously in size and shape
but all have 3 components
 cell body or soma
 contains genetic material, provides nutrients,
1. neurons – 10 to 100 billion neurons
can vary tremendously in size and shape but
all have 3 components
 cell body or soma
 contains genetic material, provides nutrients,
 Dendrites
 Primarily responsible for receiving info from adjacent
neurons
neurons – 10 to 100 billion neurons
◦
cell body or soma
 dendrites
 axons –
 Primarily important for conveying info
from one neuron to the next
Information flow

motor neurons
◦ efferent – carry info from CNS
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sensory neurons
◦ afferent – carry info toward CNS
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interneurons
◦ carry info within regions
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Glial cells provide imp supportive role:
◦ providing nutrients to neurons
 neurotrophic factors
◦ provide support for neurons
 myelin sheaths
◦ play a role in response to neuronal injury
 astrocytes
◦ play a role in brain development
 radial glia
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CNS – Central Nervous System
◦ brain, spinal cord
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PNS – Peripheral Nervous System
1. autonomic nervous system
-
“involuntary”
role in emotion and stress


controls smooth muscles, cardiac muscles and
glands
two anatomically separate components
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“fight or flight”
◦ activated during emergencies, stress and/or arousal
 ex.
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Maintain homeostasis, energy restoration
◦ physiological changes:

Somatic nervous system
◦ conveys sensory info to the CNS and motor
commands from the CNS to the muscles
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31 pairs of spinal nerves
◦ ** NERVE – BUNDLE OF AXONS OUTSIDE THE CNS
CNS
Clusters of Nuclei
cell bodies (singular nucleus)
PNS
Ganglia
Bundles of Tracts
axons
Nerves
(singular ganglion)
Copyright © 2006 by Allyn and
Bacon
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voluntary nervous system
31 pairs of spinal nerves
◦ ** NERVE – BUNDLE OF AXONS OUTSIDE THE CNS
◦ sensory nerves
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voluntary nervous system
31 pairs of spinal nerves
◦ ** NERVE – BUNDLE OF AXONS OUTSIDE THE
CNS
◦ sensory nerves
 afferent;
 dorsal roots
 dorsal root ganglion
Section of Spinal Cord AND Spinal Nerves
◦ motor nerves
 ventral
 cell bodies in ventral horn
 efferents
Section of Spinal Cord AND Spinal Nerves
Importance of the location of injury in spinal cord
in understanding the type and extent of damage that
a person with spinal cord injury will have
Importance of the location of injury in spinal cord
in understanding the type and extent of damage that
a person with spinal cord injury will have
dermatome map
Cervical – green
Thoracic- blue
Lumbar- purple
Sacral- red
Importance of the location of injury in spinal cord
in understanding the type and extent of damage that
a person with spinal cord injury will have
A high cervical injury vs a low thoracic injury will result
in very different outcome!!!!
Christopher Reeve’s
damage was between C1
and C2
-brought to the attention of many the need for
research in spinal cord injury
- strong advocates of stem cell research
-changed our beliefs about spinal cord injury
Cranial nerves primarily serve head and face
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Cranial nerves
Differences between cranial nerves and
motor/sensory nerves
◦ Cranial go directly into brain (rather than spinal
cord)
◦ Cranial can be sensory, motor or both
sphenopalatine ganglioneuralgia
Cranial nerves primarily serve head and face
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Touch tongue to your soft palate.
◦ Underside of tongue may be warmer than the top
(which probably cooled by the Slurpee you just
chugged.
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Drink something warm
Make a mask with your hands to cover your
mouth and nose. Breathe quickly, raising the
temperature inside your mouth.
Press a warm thumb against your palate.
Wait it out.
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Swelling or compression of the 7th cranial
nerve
◦ causes:
◦ treatment:
◦ recovery:
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How is it protected?
◦ Skull
 obvious - advantages of skull
 less obvious - disadvantage- closed head injury
 coup - site of injury
 contre coup
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How is it protected?
◦ Skull
◦ CSF - cerebrospinal fluid
 CSF production
•
How is it protected?
– Skull
– CSF - cerebrospinal fluid
• CSF production
–role of ventricles
• ADV:
• DISADV:
»hydrocephaly
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How is it protected?
◦ Skull
◦ CSF - cerebrospinal fluid
◦ meninges
meninges-
infections within the meninges –
bacteria – bacterial meningitis
viral – viral meningitis
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How is it protected?
◦ Skull
◦ CSF - cerebrospinal fluid
◦ meninges
◦ blood brain barrier
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Gray matter◦ Butterfly shaped
◦ Contains cell bodies
Gray matter
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Gray matter-

white matter- axons
Section of Spinal Cord AND Spinal Nerves
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Gray matter-
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white matter
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spinal tracts – bundle of axons inside the CNS
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3 main divisions of brain
◦ hindbrain; midbrain; forebrain
Metencephalon
myelencephalon
Mesencephalon
Telencephalon
diencephalon
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medulla
hindbrain
pons
medulla
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medulla
◦ basic reflexes
 heart rate, blood pressure, respiration, vomiting
 many cranial nerves enter through the medulla
Copyright © 2006 by Allyn
and Bacon
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medulla

pons
hindbrain
pons
medulla
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medulla
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pons
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cerebellum-
hindbrain
pons
medulla
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medulla
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pons
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cerebellum◦ balance and coordination
◦ motor memory
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Sensory information
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movement
◦ substantia nigra -
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Cerebral cortex
◦ role of convolutions
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Frontal
◦ Motor function
frontal
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Frontal
◦ Motor function
◦ Prefrontal – higher “executive function”
Prefrontal cortex
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Frontal
◦ Motor function
 Prefrontal – higher “executive function”
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Parietal
◦ Somatosensory function
frontal
parietal
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Frontal
◦ Motor function
 Prefrontal – higher “executive function”
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Parietal
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Temporal
◦ Somatosensory function
◦ Audition
◦ Emotion
frontal
parietal
temporal
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Frontal
◦ Motor function
 Prefrontal – higher “executive function”
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Parietal
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Temporal
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Occipital
◦ Somatosensory function
◦ Audition
◦ emotion
◦ vision
frontal
parietal
temporal
occipital
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Different roles for primary and association
◦ Start with primary motor since it is different than
the others!
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Primary motor
◦ Sends commands to muscles (via motor neurons)
primary motor strip
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Primary motor
◦ Sends commands to muscles
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Association cortex
◦ Sends coordinated commands to primary motor
cortex
Motor association cortex
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Primary sensory cortex –
◦ Receives sensory input from that sensory system
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Association cortex◦ Interprets the input (info) that comes in from the
sensory neurons
Association cortex
Visual association
cortex
Auditory association cortex
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thalamus – important relay for sensory and
motor information
has tremendous projections of neurons
across many regions of the cerebral cortex
The thalamus communicates with much of the cerebral cortex serving as a sensory and motor information relay.
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hypothalamus
◦ 4 F’s – feeding, fleeing, fighting and copulating
◦ hypothalamus contains many nuclei (collections of cell
bodies in CNS)
 also…. controls maternal behaviors (at least in rodents)
 thirst and drinking
Two brothers – same exact age.
One with a lesion (damage) to a nucleus
in the hypothalamus
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limbic system – number of structures
important in emotion
◦ limbic system also includes the hippocampus –
important for learning and memory!
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basal ganglia
◦ important in Parkinsons Disease
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corpus callosum – sole purpose of the corpus
callosum is to serve as a “bridge” between
left and right hemispheres
◦ contains millions and millions of axons
◦ allows left and right side of brain to know what
each other is doing!
Corpus callosum