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Set
Cornell Notes on pg.
29.2upNeurons
47
•Topic: 29.2 Nervous
System and Neurons
Nervous
2.129.2
Atoms,
Ions, System and Neurons
and Molecules
•Essential Question(s):
1. Draw and label a neuron
on pg. 46 in picture bubble
map format.
KEY CONCEPT
The nervous
system is
composed of
highly
specialized
cells.
29.2 Neurons
KEY CONCEPT
The nervous system is composed of highly specialized
cells.
29.2 Neurons
Neurons (aka nerve cells)are cells that can
store information and send and receive
messages within the nervous system.
• Make up an information network
(Like the internet)
Cell body
axon
Dendrites
neurotransmitter
29.2 Neurons
Neurons are highly specialized cells.
• A neuron has three parts.
1. cell body has nucleus and organelles
1
Cell body
29.2 Neurons
Neurons are highly specialized cells.
• A neuron has three parts.
1. cell body has nucleus and organelles
2. dendrites receive messages from neighboring cells
2
dendrites
29.2 Neurons
Neurons are highly specialized cells.
• A neuron has three parts.
1. cell body has nucleus and organelles
2. dendrites receive messages from neighboring cells
3. axon carries messages to other cells
Specialized support cells- such as the myelin sheathinsulate neurons’ axons and helps them send messages
3
axon
29.2 Neurons
Synapse: Gaps between neurons
Synapse
29.2 Neurons
Neurotransmitters: Chemical signals released by
neurons. Carry information from neuron to neuron.
Neurotransmitters
29.2 Neurons
Action Potential: Electrical impulse that carries
messages
Dendrites receive
action potential
29.2 Neurons
NEURON
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NEURON
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NEURON
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NEURON
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NEURON
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NEURON
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NEURON
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NEURON
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NEURON
Dendrites of
next neuron
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Axon terminal: releases neurotransmitters (chemical
signals)
Synapse
Axon terminal
(gap)
Dendrites of
next neuron
29.2 Neurons
Draw and label this neuron on p. 46:
Neurotransmitters
NEURON
Synapse
Cell body
axon
Myelin sheath
Dendrites
Action potential
Axon terminal
29.2 Neurons
• Neurons transmit information in the form of electrical and
chemical impulses
– When a neuron is stimulated, it produces an electrical
signal (action potential) within that neuron
– Before it can move to the next cell it changes into a
chemical signal (neurotransmitter)
– You react
29.2 Neurons
– Electrical Impulse reaches terminal.
terminal
impulse
29.2 Neurons
– Electrical Impulse reaches terminal.
impulse
29.2 Neurons
– Electrical Impulse reaches terminal.
– Neurotransmitters (chemicals) release into synapse.
synapse
impulse
neurotransmitte
vesicles
receptor
29.2 Neurons
– Electrical Impulse reaches terminal.
– Neurotransmitters (chemicals) release into synapse.
– Neurotransmitters stimulate next cell.
synapse
impulse
neurotransmitter
vesicles
receptor
29.2 Neurons
How does the structure of a neuron
make it effective in carrying out the
functions of the nervous system?
29.2 Neurons
How does the structure of a neuron
make it effective in carrying out the
functions of the nervous system?
Neurons have long extensions called
axons, which allow messages to be
carried long distances without having
to pass the signal to another cell.
29.2 NeuronsTypes of Neurons Picture Tree Map
Sensory Neurons
Interneurons
Motor Neurons
• Function
• Location
• Function
• Location
• Function
• Location
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29.2 Neurons
There are 3 types of neurons:
1) Sensory neurons
2) Interneurons
3) Motor neurons
29.2 Neurons
1. Sensory Neurons:
• The dendrites of these neurons act as sensory
receptors
• Function: They gather information and carry
impulses into the brain and spinal cord
•Located in PNS
Outside:
Light
&
Sound
Intensities
Inside:
Temperature
Oxygen Levels
pH Levels
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29.2 Neurons
2)Interneurons:
• Receive signals from sensory neurons and relay them
within the brain and spinal cord
• Function: Process and interpret messages in the CNS
• Located in CNS
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29.2 Neurons
3)Motor neurons:
• Pass messages from the central nervous system to
the other tissues in the body, such as muscles
• Function: Carry nerve impulses out of the brain
or spinal cord to effectors
•Effectors: muscles and glands
• Located in the PNS.
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29.2 Neurons
Key: Motor Neurons
Interneurons
Effectors
Receptors
Sensory Neurons
1._______________
2. ________________
3.
______________
4. _____________
5._____________
33
29.2 Neurons
1. Receptors
2. Sensory Neurons
3. Interneurons
4. Motor Neurons
5. Effectors
34
29.2 Neurons
In a nutshell….
• The nervous system can:
• Detect changes in the body
• Make decisions based on the info received
• Stimulate muscles and/or glands to respond
• Counteract changes to maintain homeostasis
35
29.2 Neurons
Neurons (nerve cells) are cells that can store
information and send and receive messages.
In a paragraph, hypothesize
how drug or alcohol use
might affect neurons?