Download The Nervous System

The Nervous System
Our electrochemical controls
Human Body Systems
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The Nervous System
controls the function of all of
the other systems in the
body.
Through this regulation the
body can maintain
homeostasis.
Movement, digestion,
circulation, breathing and
many other body functions
are all controlled by the
responses of the nervous
system.
Neurons
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The cells that transmit the electrical signals of the nervous
system are called neurons
Sensory neurons carry information (impulses) from the
sense organs to the central nervous system (CNS).
Motor neurons carry information (impulses) from the central
nervous system (CNS) to the muscles and glands.
Interneurons, found in the CNS, connect the two.
Structure of a neuron
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The neurons consist of:
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A cell body, where the
nucleus is contained.
Dendrites, which picks up the
impulse and carries it to the
cell body
And Axons, which carry the
impulse away from the cell
body. Axons end in axon
terminals.
The impulse is an electrical
impulse while it is traveling
along the neuron.
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The Myelin Sheath
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Schwann cells create a
myelin sheath around
each axon.
Exposed regions, called
the nodes of Ranvier,
plays an important part in
the propagation of the
nerve impulse.
Myelin increases speed
of signal.
Action Potential
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For a neuron to reach
an action potential, it
must reverse the
electrical charge
across the cell
membrane.
Once the action
potential reaches the
end of the axon,
neurotransmitters are
released into the
synapse.
The Synapse
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The junction of an axon
with another cell is called a
synapse.
This junction can be with
another neuron, muscles
or glands. All receiving
cells have receptors.
Chemicals, called
neurotransmitters, are
released into the synapse
to transmit the impulse
from one neuron to the
next, or to the receptor
tissue.
Central Nervous System (CNS)
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The nervous system is
divided into two parts.
The first part is the
central nervous
system (CNS), which is
made up of the brain
and the spinal cord.
Function is to relay,
analyze and process
information.
The Brain
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The brain is made up of:
The cerebrum, which is
where thinking takes
place.
The cerebellum, controls
balance, coordination and
voluntary actions.
The brain stem, controls
breathing, heartbeat and
blood pressure.
Involuntary actions.
The Spinal Cord
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The spinal cord carries
the nervous impulses to
different levels of the
body.
An injury to the spinal
cord would affect all of
the areas serviced
below the injury.
If you injured the
lumbar region, what
would be affected?
Peripheral Nervous System
(PNS)
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The peripheral nervous
system (PNS), is made
up of all of the nerves
that are not part of the
brain and spinal cord.
It is made up of the
sensory and motor
divisions.
The motor division of
the PNS is further
divided into the somatic
and autonomic
nervous systems.
Motor: Somatic Nervous
System
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The somatic nervous
system is the nervous
system that we can
control.
After the brain has
processed the
information, the somatic
motor neurons respond.
Some somatic nerves are
used in reflex arcs and
are not under our
conscious control.
Ex: dancing or video
games
Motor: Autonomic Nervous
System
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We do not control the ANS,
therefore, it is said to be under
involuntary control.
The ANS allows for
homeostasis to occur.
These nerves have opposite
effects on the organs they
control, one nerve will speed
up the heart and another will
slow it down
It is not on and off, it is more
like gas and brake.
Overview
Nerve video…frogs