Nervous system vocab Flashcards
stimulus
A change in an organism’s surroundings that causes the organism to react
response
An action or change in behavior that occurs as a result of a stimulus.
neuron
cells of the nervous system specialized to transmit mes-
sages throughout the body
soma
The cell body of a neuron which contains most of the cell’s organelles
dendrites
Branchlike parts of a neuron that are specialized to receive
information
axon
Long nerve fiber that conducts impulses away from the cell
body of the neuron
myelin
a white fatty substance that insulates and protects the axon
synapse
Location at which a neuron can transfer an impulse to another cell
neurotransmitter
Chemical messengers that cross the synaptic gaps between neurons
glial cells
Cells in the nervous system that support, nourish, and protect neurons
membrane potential
the difference in electric potential between the two sides
of a cell membrane
action potential
Reversal of charges across the cell membrane of a neuron; also called a nerve impulse
depolarization
loss or reduction of negative membrane potential (less negative charge inside cell than outside)
repolarization
Movement of the membrane potential to the initial resting
(polarized) state; K+ moves out of axon
sensory neuron
The nerve cell that carries afferent impulses from a sense
receptor to the brain or spinal cord
interneuron
Located in the CNS; transmits impulses between neurons;
completes pathways between afferent and efferent neu-
rons
motor neuron
a neuron that sends an efferent impulse to a muscle or
gland, causing the muscle or gland to react
central nervous system
the brain and spinal cord
peripheral nervous system
The network of afferent and efferent nerves that connects
the brain and spinal cord to other parts of the body
cerebrum
Area of the brain responsible for all voluntary activities of the body
cerebellum
posterior part of the brain that coordinates muscle movements and maintains balance
brain stem
Located at the base of the brain and controls involuntary
actions; midbrain, pons and medulla oblongata
sympathetic nervous system
the division of the autonomic nervous system that arouses
the body, mobilizing its energy during a flight or fight
response
parasympathetic nervous system
the division of the autonomic nervous system that calms
the body, conserving its energy
