Download THE NERVOUS SYSTEM

JOSE S. SANTIAGO M.D.
Nervous System
 CNS (central nervous system)
 Spinal cord
 Brain
 Peripheral nervous system
 Sensory neurons
 Motor neurons
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Functions of the Nervous System
 Sensory input – gathering information
 To monitor changes occurring inside and
outside the body
 Changes = stimuli
 Integration
 To process and interpret sensory input and
decide if action is needed
Functions of the Nervous System
 Motor output
 A response to integrated stimuli
 The response activates muscles or glands
Nerve Cells
 Neurons
 Cell body
 Axon

Some have myelin sheath
 Dendrites
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Neuron Anatomy
 Cell body
 Nucleus
 Large
nucleolus
Figure 7.4a
Neuron Anatomy
 Extensions
outside the cell
body
 Dendrites –
conduct
impulses toward
the cell body
 Axons – conduct
impulses away
from the cell
body
Figure 7.4a
Nerve Cells
 Neuroglia
 Do not carry electrical impulses
 Protect the neurons by phagocytosis
 Provide nutrients
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Synapses
 Synapse
 Electrical impulse transmission
 Gap between neuron and a muscle or between two
neurons
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Synapses
 Neurotransmitters of the peripheral nervous system
 Released from sac at end of neuron
 Acetylcholine and Norepinephrine
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The Brain
 Part of the CNS
 Cerebrum
 Hemispheres divided by longitudinal fissure
 Corpus callosum connect the hemispheres
 Cerebral cortex
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The Brain
 Cerebrum
 Gyri (convolutions)

Sulci and fissures
 Lobes
 Frontal, parietal, temporal,
and occipital
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Cerebral Hemispheres
(Cerebrum)
 The surface
is made of
ridges (gyri)
and grooves
(sulci)
Figure 7.13a
Brain
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Brain
 Thalamus
 Hypothalamus
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Brain
 Brain stem
 Midbrain
 Pons
 Medulla oblongata
 Cerebellum
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The Spinal Cord
 Part of the CNS
 Starts at the medulla
oblongata and ends at
the conus medullaris
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The Spinal Cord
 31 pairs of nerves
 8 cervical
 12 thoracic
 5 lumbar
 5 sacral
 1 coccygeal
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Spinal Cord
 Meninges -
protective
membranes
 Dura mater-tough,
protective
connective tissue;
tightly bound to the
skull; encases the
cerebral veins
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Spinal Cord
 Arachnoid mater-
web-like strands of
connective tissue
 Pia mater- thin
permeable
membrane
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Spinal Cord
 Subdural space
 Subarachnoid space-
contains CSF and
arteries
 Cerebrospinal fluidsecreted by the choroid
plexus
 Blood-brain barrier
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Spinal Cord
 Blood-brain barrier-
protection for the brain
against undesirable
blood substances
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Peripheral
Nervous System
 Cranial nerves
 12 pairs
 Emerge bilaterally from base of the skull
 Spinal nerves
 31 pairs
 Emerge bilaterally from the spinal cord
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Spinal Nerves
 There is a pair of spinal
nerves at the level of each
vertebrae for a total of 31
pairs
 Spinal nerves are formed
by the combination of the
ventral and dorsal roots of
the spinal cord
 Spinal nerves are named
for the region from which
they arise
Additional Word Parts – Roots
 Myelin/o
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myelin sheath
Roots
 Cerebell/o
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cerebellum
Roots
 Cerebr/o
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brain
Roots
 Cortic/o
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cortex; outer
covering
Roots
 Dur/o
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dura mater
Prefixes
 Pachy-
thick
 Pachymeninx- dura mater
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Roots
 Encephal/o
-brain
 Encephalitisinflammation of
the brain
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Roots
 Magnet/o-magnet
 Magnetic Resonance
Imaging (MRI)produces picture of
brain using
magnetic waves
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Roots
 Hydr/o
-water
 Hydrocephalusaccumulation of
fluid in the brain
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Roots
 Ventricul/o-
ventricles
 Ventricles-hollow cavities inside the
brain
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Roots
 Vertricul/o-
ventricles
 Ventriculostomy
-new opening in
the ventricles; for
treating
hydrocephalus
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Suffixes
 -oma
-tumor
 Hematomaaccumulation of
blood in a space
 Epidural
hematoma-blood in
the epidural space
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Suffixes
 -oma
-tumor
 Hematomaaccumulation of
blood in a space
 Subdural
hematoma-blood in
the subdural space
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Types of Brain Hematoma
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