Nervous System

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Nervous System

• Divided into 2 classes
• Central nervous system
• 2. Peripheral nervous system
• The basic anatomic and functional unit of both
  systems is the neuron

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CELL BODY
Synapses
Dendrites
Nucleus
Myelin sheath
AXON
Schwann cell
Node of Ranvier
Synaptic terminals
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Central Nervous System

• Cerebrum
• Two halves are hemispheres
• Covered in sulci and gyri
• Divided into 4 lobes
• Frontal
• Parietal
• Temporal
• Occipital

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Landmarks of Cerebrum

• Fissure of Sylvius (Lateral Fissure)
• Fissure of Rolando (Central Sulcus)
• Primary motor cortex (precentral gyrus)
• Brocas area
• Primary auditory cortex (Heschls gyrus)
• Wernickes area
• Primary sensory cortex (postcentral gyrus)

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Parietal lobe
Frontal lobe
Occipital lobe
Temporal lobe
Cerebellum
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Primary motor cortex (M1)
Posterior parietal cortex
Supplementary motor cortex (SMA)
Premotor cortex (PMA)
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Primary motor cortex (M1)
Hip
Trunk
Arm
Hand
Foot
Face
Tongue
Larynx
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Sub-cortical structures

• Basal ganglia
• Putamen
• Caudate nucleus
• Globus pallidus
• Thalamus (primary sensory/motor relay station)

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CerebellumCoordinates fine motor movement
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Brainstem
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Nerve fiber tracts

• Projection fibers
• Corticobulbar tract
• Corticospinal tract
• Association fibers
• Arcuate fasciculus
• Commissural fibers
• Corpus callosum

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Arcuate fasciculus

• Primary association tract for speech and language
• Connects Brocas area of the frontal lobe to
  Wernickes area in the tempo-parietal region

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Corpus Callosum

• Connects one hemisphere to the other
• Allows right brain to communicate with the left
  brain

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Nerve fiber tracts

• Pyramidal tract
• Direct tract
• Single point of synapse (monosynaptic)
• Voluntary muscle movement
• Projection fibers originate in cortex
• Corticospinal tracts
• Corticobulbar tracts
• http//pathology.mc.duke.edu/neuropath/nawr/motor-
  systems.html

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Nerve fiber tracts

• Extrapyramidal tract
• Indirect tract
• Multiple points of synapse (polysynaptic)
• Basal ganglia, thalamus
• Moderator of movement (muscle tone, etc.)
• Involuntary movement is an indicator of damage to
  this system