Copyright © Allyn & Bacon 2008 People Defining Development (Chapter 13)
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Transcript of Copyright © 2006 by Allyn and Bacon
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Chapter 3The Anatomy of the Nervous SystemThe Systems, Structures, and Cells that Make Up Your Nervous SystemThis multimedia product and its contents are
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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
spineServes to bring information into the
CNS and carry signals out of the CNS
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General Layout of the Nervous System
Peripheral Nervous SystemSomatic Nervous System
Afferent nerves (sensory) Efferent nerves (motor)
Autonomic Nervous System Sympathetic and parasympathetic nerves Both are efferent
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Autonomic Nervous System
All nerves are efferent Sympathetic and parasympathetic
nerves generally have opposite effects
Two-stage neural paths, neuron exiting the CNS synapses on a second-stage neuron before the target organ
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Autonomic Nervous System
Sympathetic Thoracolumbar “fight or flight” Second stage
neurons are far from the target organ
Parasympathetic Craniosacral “rest and restore” Second stage
neurons are near the target organ
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Meninges, Ventricles, and CSF
CNS - encased in bone and covered by three meningesDura mater - tough outer membrane
Arachnoid membrane - weblikePia mater - adheres to CNS surface
Cerebrospinal fluid (CSF)Fluid serves as cushion
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Protecting the Brain
Chemical protectionThe blood-brain barrier – tightly-packed
cells of blood vessel walls prevent entry of many molecules
Physical protectionSkull MeningesCerebrospinal fluid (CSF)
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Cells of the Nervous System
Neurons – structural classesMultipolarUnipolarBipolarInterneurons
Glial cells – various types, provide a wide variety of supportive functions
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Glial Cells
Myelin producersOligodendrocytes (CNS)Schwann cells (PNS)
Astrocytes – largest glia, many functions
Microglia – involved in response to injury or disease
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Terminology Note
CNS PNSMyelin-providing glia
Oligodendrocytes Schwann Cells
Clusters of cell bodies
Nuclei (singular nucleus)
Ganglia(singular ganglion)
Bundles of axons
Tracts Nerves
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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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Neuroanatomical Tracing Techniques
Anterograde (forward)tracing where axons project
to Retrograde (backward)
tracing where axons are projecting from
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Neuroanatomical Directions
In humans, the spinal cord is bent. Top of the head = dorsal or superior Back = dorsal Medial – towards the middle Lateral – towards 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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The Spinal Cord
Gray matter – inner component – primarily cell bodies
White matter – outer – mainly myelinated axons
Dorsal – afferent, sensory Ventral – efferent, motor
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The Five Major Divisions of the Brain
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The Five Major Divisions of the Brain
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Major Structures of the Brain
Myelencephalon = medullaComposed largely of tractsOrigin of the reticular formation
MetencephalonMany tractsPons – ventral surfaceCerebellum - coordination
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Major Structures of the Brain
Mesencephalon Tectum (dorsal surface)
Inferior colliculi – audition
Superior colliculi - vision
Tegmentum (ventral) – 3 ‘colorful’ structuresPeriaqueductal gray – analgesia
Substantia nigra – sensorimotor
Red nucleus– sensorimotor
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Major Structures of the Brain
DiencephalonThalamus – sensory relay nucleiHypothalamus
Regulation of motivated behaviors Controls hormone release by the pituitary
TelencephalonCerebral cortexLimbic systemBasal ganglia
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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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Telencephalon – Subcortical structures
Limbic system – regulation of motivated behaviorsMammillary bodies, hippocampus,
amygdala, fornix, cingulate, septum Basal ganglia motor system
Amygdala, striatum (caudate nucleus + putamen), globus pallidus
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