Term
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Definition
| sensory neuron connected to a motor neuron connected to a muscle cell |
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Term
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Definition
specialized cells of the nervous system that recieve, encode and transmit information -neurons + glial cells make up the nervous system -composed of four regions - cell body, dendrites, axon, and axon terminals |
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Term
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Definition
| recieve information and convert or transduce it into electrical signals |
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Term
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Definition
-muscles and glands -recieve signals communicated from the nervous system to cause behavioral or physiological response |
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Term
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Definition
cluster of neurons -frequently one pair of ganglia is larger and more central in an organism and is given the designation "brain" |
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Term
| CNS - central nervous system |
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Definition
In vertebrates, most of the cells of the nervous
system are found in the brain and the spinal cord,
which together are called the central nervous
system -information is transmitted to the CNS via sensory cells and from the CNS to effectors via neurons |
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Term
| PNS - peripheral nervous system |
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Definition
Neurons and supporting cells found outside the
CNS |
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Term
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Definition
| contains the nucleus and most of the cells organelles |
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Term
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Definition
projections from the cell body that bring
information from other neurons or sensory cells
to the cell body |
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Term
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Definition
carries information away from the cell body -conduct information to target cells (other neurons, muscle cells, or gland cells) |
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Term
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Definition
located at the end of the axon, it has many fine nerve endings -the axon terminal is positions very close to the target cell -nerve impulses cause the release of neurotransmitters (chemical messengers) into the synapse |
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Term
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Definition
the difference in voltage across the plasma membrane of a neuron -of a resting axon is about -60 miliVolts mV |
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Term
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Definition
| the voltage difference in an unstimulated neuron |
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Term
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Definition
use energy to move ions against their concentration gradient -the major ion pump in neural membranes is the sodium–potassium pump (Na+/K+ ATPase), which expels Na+ ions from the cell, exchanging
them for K+ ions from outside the cell -This keeps the concentration of K+ greater inside
the cell than outside |
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Term
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Definition
are pores formed by proteins in the
lipid bilayer that selectively allow ions to pass
through. |
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Term
potassium equilibrium
potential |
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Definition
the
tendency of K+ ions to diffuse into the cell is
equal to their tendency to diffuse out |
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Term
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Definition
When the inside of a neuron becomes less
negative in comparison to its resting condition |
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Term
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Definition
when the inside of a neuron becomes
more negative in comparison to its resting
condition |
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Term
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Definition
are action potentials that travel along
axons. |
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Term
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Definition
-a sudden and major change in
membrane potential that lasts for about 1–2 milliseconds at speeds up to 100 meter per second -During an action potential, the voltage changes from the resting potential of –60 mV to +50 mV, then rapidly returns to the resting potential -primarily caused by voltage-gated sodium channels -travel faster in large-diameter axons
than in small-diameter axons and are self regenerating |
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Term
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Definition
the time when
a plasma membrane cannot propagate an action
potential |
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Term
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Definition
| allows single ion channels to be studied |
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Term
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Definition
| to increase the diameter of the axon, the axon is wrapped with myelin sheath |
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Term
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Definition
electrically insulates the axon (charged ions
cannot cross the regions of the axon that are
wrapped in myelin) |
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Term
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Definition
| ion channels are clustered here in between myelin sheath |
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Term
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Definition
When an action potential fires at one node of
Ranvier, it jumps to the next over the myelin sheaths |
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Term
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Definition
-Gradual destruction of myelin -autoimmune disease that affects the central nervous system (CNS) -no cure |
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Term
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Definition
A synapse is an axon terminal that contains many
vesicles filled with chemical messenger molecules
know as neurotransmitters |
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Term
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Definition
-is the neurotransmitter used by all vertebrate motor neurons -released when the vesicles fuse with the presynaptic membrane and moves into the narrow space called the synaptic cleft |
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Term
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Definition
If a postsynaptic neuron responds to chemical
stimulation by depolarizing, the synapse is
excitatory. |
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Term
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Definition
If the postsynaptic neuron hyperpolarizes, the
synapse is inhibitory -(GABA) and glycine are most common |
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Term
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Definition
adds up the simultaneous
influences of synapses at different sites on the
postsynaptic cell -"several synapses fire at the sime time" |
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Term
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Definition
adds up postsynaptic
potentials generated at the same site in a rapid
sequence. -"same synapse fires rapidly" |
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