Absolute refractory period
A brief period during the action potential in which the neuron cannot be fired again because the sodium channels are closed.
An abrupt depolarization of the membrane that allows the neuron to communicate over long distances.
Any substance that mimics or enhances the effect of a neurontransmitter.
The principle that an action potential occurs at full strength or it does not occur at all
Any substance that reduces the effect of a neurotransmitter
A receptor on a neuron terminal that senses the amount of transmitter in the synaptic cleft and reduces the presynaptic neuron's output when the level is excessive.
An extnsion from a neuron's cell body that carries information to other locations
and structures that produce proteins, convert nutrients into energy, and eliminate waste materials.
The idea that a neuron is able to release only one neurotransmitter
Extensions that branch out from the neuron cell body and receive information from other neurons.
The force by which like-charged ions are repelled by each other and opposite-charged ions are attracted to each other.
excitatory postsynaptic potential (EPSP)
A hypopolarization of the dendrites and cell body, which makes the neuron more likely to fire.
Force of diffusion
The force that moves ions from an area of greater concentration to an area where they are less concentrated
Nonneural cell that provides a number of supporting functions to neurons, including myelination.
A voltage change in a neuron that varies with the strength of the stimulus that initiated it.
An increase in the polarization of a neuron membrane, which is inhibitory and makes an action potential less likely to occur.
A decrease in the polarization of a neuron membrane, which is exitatory and makes an action potential more likey to occur.
Inhibitory postsynaptic potential (IPSP)
A hyperpolarization of the dendrites and cell body, which makes a neuron less likey to fire.
A neuron that has a short axon or no axon at all and connects one neuron to another in the same part of the central nervous system.
An atom that is charged because it has lost or gained one or more electrons.
A receptor on a neuron membrane that opens ion channels directly and immediatley to produce quick reactions.
A receptor on a neuron membrane that opens ion channels slowly through a metabolic process and produces long-lasting effects.
A neuron that carries commands to the muscles and organs
A fatty tissue that wraps around an axon to insulate it from the surronding fluid and from other neurons.
A group of neurons that function together to carry out a process.
a single neural cell, in contrast to a nerve.
substance that impairs the function of a neuron.
A chemical substance that a neuron releases to carry a message across the synapse to the next neuron or to a muscle or organ.
Node of Ranvier
A gap in the myelin sheath covering an axon
When a neuron travels down the axon without any decrease in size, propagated anew and at full strength at each successive point along the way.
A type of glial cell that forms the myelin covering of neurons in the brain and spinal cord.
A difference in electical charge between the inside and outside of a neuron.
Term referring to a neuron that receives transmission from another neuron
Term referring to a neuron that transmits to another neuron.
Increased release of neurotransmitter from a neuron's terminal as the results of another neuron's release of neurotransmitter onto the terminal ( an axoaxonic synapse).
Decreased release of neurotransmitter from a neuron's terminal as the result of another neuron's release of neurotransmitter onto the terminal ( an axoaxonic synapse).
Principle that intensity of a stimulus is represented in an axon by the frequency of action potentials.
Relative refractory period
Period during which a neuron can be fired again following an action potential, but only by an abovethreshold stimulus.
The difference in charge between the inside and outside of the membrane of a neuron at rest.
Process by which a neurotransmitter is taken back into the presynaptic terminals by transporters.
Conduction in the axon in which action potentials jump from one node of Ranvier to the next.
A type of glial cell that forms the myelin covering on neurons outside the brain and spinal cord.
A neuron that carries information from the body and from the outside world into the central nervous system.
Large protein molecules that move sodium ions through the neuron membrane to the outside and potassium ions back inside, helping to maintain the resting potential.
The process of combining potentials that occur simultaneously at differnt locations on the dendrites and cell body.
The conection between two neurons.
The small gap betwen a presynaptic neuron and a postsynaptic neuron.
The process of combining potentials that arrive a short tine apart on a neuron's dendrites and cell body.
also called an end bulb.
A membrane-enclosed container that stores neurotransmitter in the neuron terminal.
The difference in electical charge between two points.