Organization and Functions
of the Nervous System
Nervous System Divisions
CNS (central nervous
system)
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
Brain, Spinal Cord
12 pairs of cranial nerves
(originate from cranium)
PNS (peripheral nervous
system)

Somatic nervous system
31 pairs of spinal nerves

Autonomic nervous system
Afferent and Efferent
Nerves
12 cranial nerves
Autonomic Nervous System
Autonomic Nervous System
Sympathetic Division

Exits Thoracic-Lumbar region of
SC

Norepinephrine in postganglionic
synapses

Fight-or-Flight Response
Elevated hr, bp
Pupil dilation
Increased sweat gland activity
Dry mouth
Increased blood flow to
muscles
Parasympathetic Division

Exits Cranial and Sacral
regions of SC

Acetylcholine in
postganglionic synapses

Energy Conservation
Decreased hr, bp
Pupil constriction
Salivation
Gastric Secretion
Protection of the CNS
Meninges (3 protective layers)

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Dura Mater
Arachnoid Membrane
Pia Mater
Cerebrospinal Fluid


Buoyancy and Shock Absorption
Ventricles and subarachnoid space
Ventricular System
Dissection Planes
Neuroanatomy
Directional Terminology
Anterior – Posterior (Front –Back)
Dorsal – Ventral (Top – Bottom)
Medial – Lateral (Middle –Side)
Superior –Inferior (Above – Below)
Spinal Cord
Brain Divisions
Four Cerebral Lobes
Midsagittal View of Brain
Ventral Surface of Brain
Cerebral Cortex
Basal Ganglia
Three Main Components



Caudate Nucleus
Putamen
Globus Pallidus
Major Functions


Motor Control
Somatosensory-Motor
Integration
Diseases of the BG


Parkinson’s Disease
Huntington’s Disease
Limbic System
Limbic Structures: a group of structures surrounding
the brain stem
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Cingulate Cortex
Hippocampus
Amygdala
Mammillary Bodies
Anterior Hypothalamus
Fornix
Functions


Emotions
Memory
Diencephalon
Thalamus



Two lobes at the anterior portion of the brain stem surrounding
the third ventricle, joined by massa intermedia
Interconnected with Cerebral Cortex and with Cerebellum
Major Sensory Relay
Vision: Lateral Geniculate Nucleus
Hearing: Medial Geniculate Nucleus
Touch: Ventral Posterior Nucleus
Smell: Medial Dorsal Nucleus
Taste: Ventral Posterior Nucleus
Diencephalon
Hypothalamus



Located below the anterior thalamus
Contains several subdivisions and interconnected
with limbic system regions
Detection of need states, involved in hormone and
temperature, fluid & nutrient regulation
Brain Stem
Brain Stem—midbrain + hindbrain
(minus the cerebellum)
Mesencephalon (Midbrain)
Tectum (“roof”)

relays visual and auditory information and
controls simple reflexes, eye and ear
orientation movements
superior colliculi (“little hills”)—relay visual
information
inferior colliculi—relay auditory information
Mesencephalon (Midbrain)
Tegmentum (“floor covering”)



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Substantia nigra—integration of
voluntary movements
Red nucleus—controls basic body
movements
Reticular formation—controls arousal
and consciousness
Raphé system
The Hindbrain
The Hindbrain
Metencephalon

Pons—a “bridge” for many fibers passing from
one side of the brain to the other.
Contains sensory fibers, fibers from the cortex to
cerebellum, and fibers that relay information on
sleep, arousal, muscle tone, and dreaming.

Cerebellum—involved in the development and
coordination of movement
Myelencephalon

Medulla Oblongata
Cranial nerve nuclei
Regulates basic life functions (e.g., respiration, heart
rate, vomiting, salivation)
Cerebellum
Components


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Vermis
Lateral zone
Flocculonodular lobe
Cell Layers

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Molecular Layer
Purkinje Cell Layer
Granule Cell Layer
Major Functions

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Balance
Motor Coordination
Timing and sequencing of
rapid movements
Sensorimotor Learning
Cognition?