1. The Systems, Structures, and Cells That Make Up Your Nervous System
Chapter 3
The Anatomy of the
Nervous System
The Systems, Structures, and Cells That Make Up Your Nervous System

2. General Layout of the Nervous System
Central Nervous System (CNS)
Brain (in the skull)
Spinal Cord (in the spine)
Peripheral Nervous System (PNS)
Located outside of the skull and spine
Serves to bring information into the CNS and carry signals out of the CNS
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Major divisions of the nervous system
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4. Meninges, Ventricles, and Cerebrospinal Fluid (CSF)
CNS encased in bone and covered by three meninges
Dura mater – tough outer membrane
Arachnoid membrane – web-like
Pia mater – adheres to CNS surface
Cerebrospinal fluid (CSF)
Fluid serves as cushion
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5. Meninges http://faculty. une. edu/com/fwillard/Meninges/pages/mening02

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Protecting the Brain
Chemical protection
The blood-brain barrier – tightly-packed cells of blood vessel walls prevent entry of many molecules
Physical protection
Skull
Meninges
Cerebrospinal fluid (CSF)
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7. Cells of the Nervous System
Neurons
Specialized cells for the reception, conduction, and transmission of electrochemical signals
Many sizes and shapes
Glial cells
Outnumber neurons 10:1
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8. Cells of the Nervous System Major external features of
a typical neuron
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Cells of the Nervous System (continued)
The
cell
mem-
brane
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10. Cells of the Nervous System (continued)
Four
types of
neurons
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11. Glial Cells: The Forgotten Majority
Four classes:
Oligodendrocytes – extensions rich in myelin create myelin sheaths in CNS
Schwann cells – similar to function of oligodendrocytes but in PNS, can guide axonal regeneration
Astrocytes – largest glia, star-shaped, many functions
Microglia – involved in response to injury or disease
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Terminology Note
CNS
PNS
Myelin-providing glia
Oligodendrocytes
Schwann cells
Clusters of cell bodies
Nuclei
(singular nucleus)
Ganglia
(singular ganglion)
Bundles of axons
Tracts
Nerves
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15. Neuroanatomical Techniques
Golgi stain – allows for visualization of individual neurons
Nissl stain – selectively stains cell bodies
Electron microscopy – provides information about the details of neuronal structure
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16. Neuroanatomical Tracing Techniques
Anterograde (forward)
tracing where axons project away from an area
Retrograde (backward)
tracing where axons are projecting into an area
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Directions in the Vertebrate Nervous System
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Directions in the Vertebrate Nervous System (continued)
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19. Directions in the Vertebrate Nervous System (continued)
Anatomical directions ignore the fact that humans walk upright. Therefore, top of the head both “dorsal” (back) and “superior” (top)
Other directions:
Medial – toward the middle
Lateral – toward the side
Proximal – close
Distal – far
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Sections of the Brain
Horizontal – a slice parallel to the ground
Frontal (coronal) – slicing bread or salami
Sagittal – a midsagittal section separates the left and right halves
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section
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The Spinal Cord
Gray matter – inner component, primarily cell bodies
White matter – outer area, mainly myelinated axons
Dorsal – afferent, sensory
Ventral – efferent, motor
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23. The Spinal Cord (continued)
Dorsal and ventral roots Spinal cross section
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24. The Five Major Divisions of the Brain
Early
develop-
ment of the
mammalian
brain
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25. The Five Major Divisions of the Brain (continued)
The divisions
of the adult
human brain
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26. Major Structures of the Brain
Myelencephalon = medulla
Composed largely of tracts
Origin of the reticular formation
Metencephalon
Many tracts
Pons – ventral surface
Cerebellum – coordination
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Major Structures
of the Brain
Structures of the
human
myelencephalon
(medulla) and
metencephalon
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Major Struc-
tures of the
Brain (continued)
The human
mesencephalon
(midbrain)
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Major
Structures
of the
Brain
(continued)
The human
diencephalon
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30. Telencephalon – Cerebral Cortex
Convolutions serve to increase surface area
Longitudinal fissure – a groove that separates right and left hemispheres
Corpus callosum – largest hemisphere-connecting tract
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Major fissures of the cerebral hemispheres Lobes of the cerebral hemispheres
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32. Telencephalon – Subcortical Structures
Limbic system – regulation of motivated behaviors
Mammillary bodies, hippocampus, amygdala, fornix, cingulate, septum
Basal ganglia motor system
Amygdala, striatum (caudate nucleus + putamen), globus pallidus
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33. Telencephalon – Subcortical Structures
The major structures of the limbic
system
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Telencephalon –
Subcortical
Structures
The basal ganglia
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35. Summary of major brain structures
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