Transcript Central and Peripheral nervous systems

The Nervous System and the
Control of Movement
The Nervous System
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The nervous system is the body's way of
gathering information, storing it, and responding
to it
Main role is to assemble information about
conditions external and internal to the body
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Analyze this information
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Initiate responses that may be necessary to satisfy
certain needs
Two Components of the Nervous System
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Brain + spinal cord = central nervous system
(CNS)
Peripheral nervous system (PNS) = responsible
for other things
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i.e. Heart
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Digestive system
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Muscular control
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All voluntary and involuntary neuromuscular
controls
The Brain
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Control centre or “computer” of the body
Incapable of performing physical tasks,
therefore it sends commands to other parts of
the body to perform them
6 main parts: cerebrum, cerebellum, brain stem,
diencephalon, limbic system, reticular activating
system
Cerebrum
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Largest part of the brain
Contains nerve centres that control sensory and
motor activities
Can be divided into two halves or
“hemispheres”
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Each hemisphere is divided into 4 lobes (named
after the bone that they lie over
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Frontal lobe, temporal lobe, parietal lobe, occipital
lobe
Cerebellum
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Second largest region
Lies behind and
below the cerebrum
Main function is to
coordinate muscle
movement and
control balance
Brain Stem
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Below cerebrum and
in front of cerebellum
Links the cerebrum
with the spinal cord
Houses brain centres
responsible for
autonomic functions,
postural control,
muscle tone, and eye
movement
Diencephalon
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Consists of thalamus
and hypothalamus
Thalamus relays most
sensory stimuli to the
cerebral cortex
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Controls awareness of
pain, screening of
incoming signals,
focusing attention
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Hypothalamus
controls body
temperature, appetite,
emotions and various
automatic functions
Limbic System
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Composed of a
collection of
structures within the
cerebral hemispheres
that regulate basic
drives i.e. Hunger,
aggression, emotional
drives
Screens information
going to the cerebral
cortex
Reticular Activating System
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Network of neurons
Fans out through the
cerebral cortex
Directs information to
appropriate centres
for interpretation
Crucial for
maintaining
consciousness
Vertebral Column and the
Spinal Cord
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Main pathway for information connecting the
brain and peripheral nervous system
Spinal cord runs through the vertebrae
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Starts from the the base of the brain stem and
travels down to the second lumbar vertebra
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Spinal nerves carry sensory information towards
the CNS and motor commands away from the CNS
Peripheral Nervous System
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Consists of the parts of the nervous system that
lie outside the CNS (everything but the brain
and spinal cord)
Carries information in and out of the CNS
Motor Nerves – aka efferent nerves carry
information from the CNS to the body's organs
Sensory Nerves – aka afferent nerves carry
information from sensory receptors to the CNS
Autonomic Nervous System
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Subsystem of the PNS
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Controls involuntary actions (i.e. Heart beat)
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Comprised of two branches which act as
opposing systems
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Sympathetic system
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Parasympathetic system
Sympathetic System
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Causes localized bodily adjustments to occur
(i.e. Sweating)
Prepares bodies for emergencies
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This involves release of adrenaline, increased heart
rate, widening of blood vessels, and “fight or flight”
responses
Parasympathetic System
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Helps to return the body to normal after it has
been altered by the sympathetic system
i.e. Sympathetic system will increase heart rate,
parasympathetic system will decrease heart
rate to bring it back to its resting state.
Somatic Nervous System
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Another subsystem of the PNS
Responsible for our awareness of the external
environment
Contains both afferent and efferent nerve fibres
Through this system, the PNS receives and
processes information from receptors in the
skin, voluntary muscles, tendons, and joints
Gives us the sensations of touch, pain, heat,
cold, balance, body position, and muscle action
Cont...
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Handles the muscles in our extremities
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Allows us to move