Anatomy of the Central Nervous System Lesson 3

Functional Anatomy: CNS Major Divisions Forebrain, Midbrain, Hindbrain Know structure location & general function Major fiber systems CNS vs PNS terminology nucleus vs. ganglion tracts vs. nerves ~

Forebrain - Cortex Gray Matter Somas and Dendrites 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 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 vision Lateral Geniculate Nuclei LGN Medial Geniculate Nuclei MGN audition ~

Hypothalamus 4Fs Feeding Fighting fleeing, and ... mating Controls the pituitary gland ~

Thalamus

Thalamus & Hypothalamus MGN LGN Hypothalamus Pituitary Stalk

Subcortical: Limbic System Emotion; Learning & Memory Structures Cingulate gyrus Hippocampus Amygdala Thalamus Hypothalamus Mammilary bodies Olfactory bulbs Fornix ~

Limbic System Cingulate gyrus Hippocampus Fornix Thalamus Hypothalamus Amygdala

Subcortical: Basal Ganglia 3 motor nuclei Caudate Putamen Globus Pallidus ~ Striatum

Caudate Globus pallidus Putamen

Midbrain Surrounds cerebral aqueduct Tectum Superior Colliculi - vision Inferior Colliculi - audition Tegmentum substantia nigra - motor many other nuclei sleep/wake cycle pain & analgesia positive reinforcement ~

Thalamus Superior Colliculi Inferior Colliculi Tectum Tegmentum Medulla

Cross-section of Tegmentum Dorsal Substantia Nigra

Hindbrain Cerebellum coordinates movements Pons Sleep and arousal Medulla vital functions many cranial nerves ~

Cerebellum Pons

Spinal Cord Dorsal Gray Matter Horns Dorsal White Matter Ventral Central Canal