Transcript Chapter 7 The Nervous System Central Nervous

Functions of the Nervous System
Sensory input –
monitor changes
occurring inside and
outside the body
 Changes = stimuli
 Done by a sensory
receptor (Ex.- Rods
and cones of eye,
olfactory neurons of
nose, touch
receptors in
integument…)
http://www.colorado.edu/intphys/Class/IPHY3430-200/image/10-4.jpg
Functions of the Nervous System
 Integration
 To process and
interpret sensory
input and decide if
action is needed
 Done in brain or
spinal cord
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Basic Tasks of the Nervous System
Sensory Input:
Monitor both
external and internal
environments.
Integration: Process
the information and
often integrate it with
stored information.
Motor output: If
necessary, signal
effector organs to
make an appropriate
response.
Functional Properties of Nervous Tissue
 Irritability – ability
to respond to
stimuli
 Conductivity –
ability to transmit
an impulse
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Structural Classification of the Nervous
System
 Central nervous system
(CNS)
 Brain
 Spinal cord
 Peripheral nervous system
(PNS)
 Nerves outside the brain and
spinal cord
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Central Nervous System (CNS)
 CNS develops from the embryonic
neural tube
 The neural tube becomes the brain and
spinal cord
 The opening of the neural tube becomes
the ventricles
 Four chambers within the brain
 Filled with cerebrospinal fluid
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Protection of the Central Nervous
System
Layers
1. Scalp and
skin
2. Skull and
vertebral
column
3. Meninges
Figure 7.16a
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Protection of the Central Nervous
System
 Cerebrospinal fluid- CSF
Produced by which cells?
 Blood brain barrier
Figure 7.16a
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Meninges
 Dura mater
 Double-layered external covering
 Periosteum – attached to surface of the skull
 Meningeal layer – outer covering of the brain
Folds inward in several areas
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Meninges
 Arachnoid
layer
 Middle layer
 Web-like
 Pia mater
 Internal layer
 Clings to the
surface of the
brain
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Higher
Brain
function
Spatial
Vision
Speech,
memory,
hearing
Motor control-Posture
& equilibrium
Autonomic Functions: breathing,
heartbeat, respiration, etc,
Regions of the Brain
 Cerebral
hemispheres
 Diencephalon
 Brain stem
 Cerebellum
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Figure 7.12
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Cerebral Hemispheres (Cerebrum)
 Paired (left
and right)
superior parts
of the brain
 Include more
than half of
the brain
mass
Figure 7.13a
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Slide
Language:
aphasias: loss of language ability due
to damage to specific areas of the brain
Broca’s Area: speaking and forming
words- damage = difficulty speaking, not
understanding
Wernicke’s area: understanding of
words
damage= “word salad”
Basal nuclei – receive information from
cerebral cortex
Regulates voluntary motor activities by modifying
info sent to the motor cortex
Problems = ie unable to control muscles, spastic,
jerky
Involved in Huntington’s
and Parkinson’s Disease
•
Crossover of Pyramids in Medulla:
Each cerebral hemisphere controls voluntary
movement in opposite side of the body
Diencephalon
Brain Stem
Traumatic Brain Injury
National TBI Estimates
Every year, at least 1.7 million TBIs occur
either as an isolated injury or along with
other injuries.
TBI is a contributing factor to a third
(30.5%) of all injury-related deaths in the
United States.
About 75% of TBIs that occur each year
are concussions or other forms of mild
TBI.
Did you know? 1- 19 yrs
• Each year, U.S. emergency departments (EDs) treat an
estimated 173,285 sports- and recreation-related TBIs
• During the last decade, ED visits for sports- and recreationrelated TBIs, including concussions, among children and
adolescents increased by 60%.
• Overall, the activities associated with the greatest number of
TBI-related ED visits included bicycling, football, playground
activities, basketball, and soccer.
• National surveillance in 9 high school sports:
• TBI represents almost 9% of all injuries reported in the 9
sports
• Numbers and rates are highest in football (55,007; 0.47 per
1000 athlete exposures) and girl’s soccer (29,167; 0.36 per
1000 athlete exposures)
Spinal Cord
 Extends from the
foramen magnum to the
region of L2
 Below is the cauda
equina (a collection of
spinal nerves)
 Enlargements occur in
the cervical and lumbar
regions
Figure 7.18
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Spinal Cord Anatomy
 Exterior white mater – conduction tracts
Figure 7.19
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Spinal Cord Anatomy
 Internal gray matter - mostly cell bodies
 Dorsal (posterior) horns
 Anterior (ventral) horns
Figure 7.19
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Spinal Cord Anatomy
 Central canal filled with cerebrospinal
fluid- continuous with CFS in Brain
Figure 7.19
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Spinal Cord Anatomy
 Meninges
 Nerves leave at
the level of each
vertebrae
 Dorsal rootsensory
neurons
 Ventral rootcontains motor
neurons
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