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Anatomy of the
Central Nervous
System
Lesson 5
Functional Anatomy: CNS
Major Divisions
 Forebrain, Midbrain, Hindbrain
 Know structure *name, location &
general function
 Major fiber systems
 CNS vs PNS terminology
 nucleus vs. ganglion
 tracts vs. nerves ~

Forebrain - Cortex
Gray Matter
 Somas and Dendrites (neuron cell
bodies)
 Organized in layers
 some input, some output
 Neocortex
 6 layers ~

Forebrain - Fiber Systems
White Matter - myelinated axons
 3 types of fiber systems
 Commissural
 Association
 Projection ~

Commissural Fibers

Interconnect homologous structures in
the two hemispheres
 Corpus Callosum
 Anterior and Posterior
 Hippocampal ~
Anterior
Anterior
Forebrain Fibers Systems



Association Fibers
 interconnect cortical areas within
each hemisphere
Projection Fibers
 all other *CNS fiber systems
 Fornix
 Corticospinal tract
 Mammillothalamic tract
Naming convention ~
Hemispheres
Left
Right
Association
Commissural
Projection
Forebrain Subcortical Areas
Diencephalon
 Surrounds 3rd ventricle
 Thalamus
 sensory and motor relay nuclei
 Hypothalamus
 motivation & emotion ~

Thalamus
Lateral Geniculate Nuclei
 LGN
 vision
 Medial Geniculate Nuclei
 MGN
 audition
~

Hypothalamus
4Fs
 Feeding
 Fighting
 fleeing, and ...
 mating
 Controls the pituitary gland ~

Subcortical: Limbic System
Emotion; Learning & Memory
 Structures
 Cingulate gyrus
 Hippocampus
 Amygdala
 Thalamus
 Hypothalamus
 Mammilary bodies
 Olfactory bulbs
 Fornix ~

Limbic System
Subcortical: Basal Ganglia

3 motor nuclei
 Caudate
 Putamen
 Globus Pallidus ~
Striatum
Midbrain
Surrounds cerebral aqueduct
 Tectum
 Superior Colliculi - vision
 Inferior Colliculi - audition
 Tegmentum
 substantia nigra - motor
 Reticular formation

sleep/wake cycle

many other nuclei ~
Cross-section of Tegmentum
Dorsal
Hindbrain
Cerebellum
 coordinates movements
 Pons
 Sleep and arousal
 Medulla
 vital functions
 many cranial nerves ~
