Download Neuron Teacher Key 5-17-16

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Teacher Key
Big Idea
Different types of neurons compose the nervous tissue that forms the communication system
within the body.
Introduction to Neurons
An individual’s survival and reproductive success depends upon the ability to sense, respond
and adapt appropriately to changes in the environment. The nervous system links sensation to
response. Nerve cells (neurons) in the nervous system are the structural units principally used
in transmitting information. Many different types of neurons with specialized structures enable
them to conduct messages effectively from one part of the body to another.
Modeling Neurons and Neuronal Structures
1. Draw your mental image of a neuron in the space below. (Various.)
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2. What are two characteristics that distinguish nerve cells from other cells?
Nerve cells are unique in that they transmit signals and utilize chemical communication.
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3. What is the difference between a nerve cell and a nerve?
A nerve cell is a specialized excitable cell for the transmission of electrical signals
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over long distances while a nerve is a fiber composed of a bundle of axons of nerve
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cells.
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4. Label these major parts of the large neuron model: dendrites, axon, soma/cell body,
nucleus, myelin sheath, Schwann cell, axon hillock, synaptic knob.
Synaptic Knob
Axon Hillock
Dendrites
Axon
Soma / Cell Body
Nucleus
Schwann Cell
Nucleus
Myelin Sheath
5. With an arrow, indicate the direction of the movement of information through the above
nerve cell. (Noted in red on the diagram above.)
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6. Sketch and identify the types of neurons modeled in the Neuron Modeling Set© in the
space below.
Bipolar
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Unipolar
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Multipolar
Interneuron
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7. Where are these neurons found in the body? How do they function? Complete the chart
below.
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Type of Neuron
Based on
Structure
Location
Functional Class
Abundance
multipolar
PNS/CNS
motor/efferent
most abundant/
major CNS
neuron
bipolar
special sense
organs
most sensory
rare
unipolar
chiefly PNS
most sensory
commonly found
in spinal cord and
cranial nerves
interneuron
CNS
Conducts impulses
most abundant
from afferent to
(over 100 billion)
motor neurons
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8. Identify the function of each of the following:
motor neuron -
a nerve cell that transmits signals from the brain or spinal
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cords (CNS) to muscels or glands
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interneuron -
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a nerve cell within the CNS that forms synapses with
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sensory and/or motor neurons and integrates sensory
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input and motor output
sensory neuron - _________________________________________________
a nerve cell that receives information from internal or external
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environments and transmits signals to the CNS
9. What is the myelin sheath?
The myelin sheath is a coat of cell membranes from Schwann cells or
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oligodendrocytes that are wrapped around the axon of a neuron.
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10. What is the function of myelin sheath?
The membranes of the cells forming the myelin sheath are composed mostly of lipids,
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which are poor conductors of electrical current and provide good insulation.
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11. Label the neuron, oligodendrocyte, and Schwann cell.
Neuron
Oligodendrocyte
Schwann Cell
Neuron
Peripheral Nervous System
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Central Nervous System
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12. Is the large neuron model a part of the PNS or the CNS? How do you know?
The neuron is part of the PNS because the myelin sheath is composed from Schwann
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cells instead of oligodendrocytes.
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13. What is a synapse? Identify where synapse junctions may occur in the body.
A synapse is the junction where a neuron communicates with another cell across a
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narrow gap.
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14. Identify where synapse junctions may occur in the body.
Synapses may occur between nerve cells, between a nerve cell and a muscle cell or
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between a nerve cell and glandular cell.
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Neuronal
Neuro- muscular
Neuro- glandular
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15. To illustrate the structural diversity among neurons, identify the types of synapses
shown in the diagram to below (axodendritic, axoaxonic, axosomatic).
Using the neurons in the kit, model each of these synapse types.
Axodendritic
Axoaxonic
Axosomatic
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