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• Central Nervous System (CNS):
brain and spinal cord
Some Basic Neuroanatomy
• Peripheral Nervous System (PNS):
all the nerves outside of the brain
& cord
Gray & White Matter
• Brain areas with lots of neuron cell bodies/dendrites look
darker (“gray matter”) & function like information
processors – receiving & combining input
• Areas with lots of myelinated axons appear lighter (“white
matter”) & function like cables connecting regions
• A group of neuron cell bodies = “nucleus” (in CNS) or
“ganglion” (in PNS)
• A bundle of axons = “tract” or “pathway” (in CNS) or
“nerve” (in PNS)
• The CNS has a continuous fluid filled canal (or “ventricle”
system throughout its length.
Anatomical Directional Terms
Vesicles Form at Head End of Developing
Nervous System
• Become familiar with the
anatomical directional
terms on p. 63
3 weeks
5 weeks
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Telencephalon – outer part of forebrain
Cerebral hemispheres
Afferent
Diencephalon – inner part of forebrain
Thalamus & Hypothalamus
5 Chunks of
of Brain
Mesencephalon - midbrain
Efferent
Metencephalon – upper part of hindbrain
Pons & Cerebellum
Myelencephalon – lower part of hindbrain
Medulla oblongata
Book 4.6
Divisions of the Nervous System
Structures Controlled by the ANS
The Brainstem
Reticular Activating System
Thalamus
Hypothalamus
• The cells of the
“reticular
formation” have
many other
functions as well.
Midbrain
Cerebellum
Pons
Medulla
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2 and 3 on the
“dorsal”
surface of
midbrain are
the primitive
visual (2) and
auditory (3)
processing
centers, the
superior (2) and
inferior (3)
colliculus.
3
2
1
Substantia Nigra Dopamine Neurons
Red Nucleus is another motor region in the midbrain
http://mindsci-clinic.com/rostral_midbrain.htm
Middle layer added emotion & memory capabilities.
Book
3.22
Substantia Nigra Dopamine Neurons
Newest outer layer added judgment, reasoning, planning
and self-control.
Red Nucleus is another motor region in the midbrain
http://mindsci-clinic.com/rostral_midbrain.htm
Book
3.22
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The Reptilian Brain
Periaqueductal Gray (PAG)
The start of a descending pain suppression system
• The brainstem, especially its core, is the most primitive
portion of our brain, relatively unchanged from the time
that dinosaurs roamed the earth. Most reptile behavior
is reflexive response to stimuli.
Mike, the Headless Chicken
• Survived 18 months
• Could still stand, sit on a perch,
walk clumsily, and attempt to
crow and preen.
• These basic behaviors are like
reflexes – built into the
brainstem.
A Sadder Example
• Anencephaly – forebrain fails to develop.
Baby has a flattened, open skull. Baby
shows basic reflexive behaviors (can nurse,
grasp, etc.) but with only hindbrain &
midbrain structures intact, survival is brief
(hours-days).
http://en.wikipedia.org/wiki/Mike_the_Headless_Chicken
Hypothalamus
• Plays a role in lots of different basic behaviors/motivations
necessary for survival of individual & survival of the
species
• The “four F’s”
•
•
•
•
Means “beneath the thalamus”
The Hypothalamus
Feeding
Fighting (aggression & rage)
Fleeing (fear behaviors)
Mating : )
• But also primitive parenting behaviors, temperature
regulation, hormone regulation, biorhythms & sleep,
mood/emotions
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The Brainstem Areas Again
The Thalamus
works closely with
regions of cortex
• Partially processing incoming sensations before
passing input on to cortex
• Part of the motor system
• Works with higher cortical regions related to
cognition, memory, personality etc.
The Brain is Like a Tootsie Pop
The Basal Ganglia Motor System
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In Front of Hypothalamus is the “Basal
Forebrain”
Another component is the nucleus basalis which sends
arousing ACh messages to all of cortex for
memory/cognition. This nucleus dies off in Alzheimer’s
disease.
One component of the basal forebrain is the nucleus
accumbens, a hub of our pleasure/reward pathway
Side View of Cortex & Cerebellum
Corpus Callosum
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Motor
cortex
Central
Sulcus
Fig27
Association
Somatosensory
cortex
cortex
Association
cortex
FRONTAL
LOBE
PARIETAL
LOBE
Broca's
area
Lateral fissure
TEMPORAL
LOBE
OCCIPITAL
LOBE
Visual
cortex
Auditory
cortex
Wernicke's
area
2 More Regions in Neocortex
Let’s add some common anatomical terminology
Neocortex Has 6 Layers With Regional
Variations in Thickness
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A “Processing Unit” Within the
Cortex is a Column of Cells
The Meninges completely
enclose the CNS and help
protect it.
“-itis” = inflammation
Meningitis= inflammation of meninges
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Filled with cerebrospinal fluid (CSF) which is replaced every few hours
Enlarged Ventricles
Due to Hydrocephalus
A Shunt Tube Drains Away Excess
CSF
https://www.youtube.com/watch?v=WU
HdkP278q0&list=PLJG4HdSoAx23j8Ev
hgzuJ3sEtCiMsqNJg&index=6
Go to 20
Glia or Glial Cells
(“supporting cells” of the nervous system)
• 10X more numerous than neurons but one-tenth the size
• make up about half of brain weight
• several distinct types
• assist neurons in multiple ways
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Form Myelin
Sheath
• Oligodendrocyte
forms CNS myelin
• Schwann cell forms
PNS myelin
• Multiple sclerosis –
patchy loss of myelin
sheaths that can interfere
with any CNS function
(depending on which
neurons lose their
insulation)
or not at all
http://www.youtube.com/watch?v=qgySDmRRzxY&feature=PlayList&p=ED18B251293C8C20&playnex
t=1&index=2
Loss of White Matter in
Multiple Sclerosis
• Astrocytes exchange materials
with neurons
• Microglia remove debris and
multiply to form scar tissue
Blood-Brain Barrier
Radial Glial Cells
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