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Student Resource 8.7
Glossary: The Nervous System
This glossary includes terms that have been introduced in Lesson 8. We have separated terms into categories to make it easier to remember
them, but many terms could fit into more than one category.
Anatomy Terms
Term
Definition
axon
A long projection in a neuron that carries a nerve impulse away from the
cell body and toward other cells.
axon terminal
Finger-like projections at the end of an axon that meet with another cell
at a synapse.
brain
One of the organs of the nervous system, the body’s central “computer”
that receives, integrates, and sends messages.
cell body
The part of a neuron where the cell’s ordinary functions are carried out.
dendrites
Tree-like extensions from the neuron cell body that collect input from
other neurons or the environment and send it toward the cell body.
glial cells
Nervous tissue cells that support and protect brain cells.
myelin sheath
A covering made of fat and protein that insulates axons and allows them
to conduct signals more quickly.
Copyright © 2014‒2015 National Academy Foundation. All rights reserved.
Notes
AOHS Foundations of Anatomy and Physiology I
Glossary Lesson 8, The Nervous System
nerve
A bundle of axons wrapped in connective tissue.
spinal cord
An organ of the nervous system and the largest nerve in the body. It is
an extension of the brain stem that carries messages between the brain
and parts of the body below the head and neck.
vesicles
Tiny sacs in the axon terminal that contain neurotransmitters to be
released into the synaptic cleft.
Physiology Terms
Term
Definition
autonomic nervous
system
Controls the activities of smooth (involuntary) muscles. These nerves go
from your spinal cord to your lungs, heart, stomach, intestines, bladder,
and sex organs.
central nervous
system
Consists of the brain and spinal cord; it handles the task of integrating
information.
depolarization
Occurs when sodium ions rush into the cell during an action potential,
raising the membrane potential from a very negative value to be more
positive. For a short time, the charges on either side of the cell
membrane switch, making the inside of the cell membrane positive
relative to the outside.
effector organ
The muscle or gland that produces the response in a reflex arc.
interneuron
Neurons that connect and create pathways between other neurons,
often connecting sensory neurons with motor neurons.
Copyright © 2014‒2015 National Academy Foundation. All rights reserved.
Notes
AOHS Foundations of Anatomy and Physiology I
Glossary Lesson 8, The Nervous System
motor division
Part of the peripheral nervous system, made of motor neurons that
receive messages from the central nervous system and respond, usually
by contracting muscle cells.
motor neuron
Neuron that receives signals from the brain and spinal cord to stimulate
muscles and glands.
parasympathetic
nervous system
Part of the autonomic nervous system: it maintains the resting state of
the body, such as heart rate and activity of the digestive system.
peripheral nervous
system
Part of the nervous system that comprises nerves outside the brain and
spinal cord; it handles sensory input and motor output.
reflex
A rapid, automatic response that results in movement or the stimulation
of a gland. Reflexes happen in both the somatic and autonomic nervous
systems.
reflex arc
The path followed by the nerve impulses that trigger and produce the
response of a reflex.
sensory division
Part of the peripheral nervous system, made of sensory neurons with
receptors that collect and convey information about the environment.
sensory neuron
Neurons that respond to stimuli from the environment and carry that
information to the central nervous system.
somatic nervous
system
Part of the peripheral nervous system; it governs the movement of
skeletal muscles, including reflexes.
sympathetic nervous
system
Part of the autonomic nervous system; it controls heartbeat and other
body functions and becomes more active when the body is subjected to
physical or emotional stress. When it is more active, the sympathetic
nervous system brings on flight-or-fight response.
Copyright © 2014‒2015 National Academy Foundation. All rights reserved.
AOHS Foundations of Anatomy and Physiology I
Glossary Lesson 8, The Nervous System
Medical Terms
Term
spinal cord injury
(SCI)
Definition
An injury to the tissue that makes up the spinal cord and that usually
results in paralysis of parts of the body below the site of the injury.
Copyright © 2014‒2015 National Academy Foundation. All rights reserved.
Notes