A spontaneous self-propagating change in membrane potential that travels as a 'wave' along electrically excitable cell membranes found in neurons and muscle cells. Action potentials are triggered when the cell's membrane potential depolarizes (i.e. becomes more positive with respect to the internal side) beyond a threshold value of usually -40mV. Voltage sensitive ion channels (Na and K channels) open and close in fast succession causing first in influx of sodium ions (making the inside more positive = depolarization) followed by potassium efflux (making the outside more positive and inside more negative = hyperpolarization). The potassium efflux brings the membrane potential below the threshold and thus to rest. A new action potential can only be triggered with a new stimulus which comes from neurotransmitter activated ion channels at locations of synaptic interaction between neurons or neurons and muscle cells.
The technical term for the 'messages' that travel along nerve cells. They are waves of electrical activity (impulses) that travel very quickly along the length of the thread-like nerve cells. When they reach the end of the nerve cell they can be passed on to other nerve cells, or to other types of cells, such as those in muscle.
the changes in electrical membrane potential which occur in muscle or nerve cells when they are stimulated.
a series of changes in the electrical charge across the axonal membrane that occurs after the axon has reached its firing threshold. 70
The long-distance signal of the nervous system. Action potentials are triggered in excitable cells in response to depolarization that exceeds the threshold potential.
An electrical impulse that propagates along neurons, and other electrically excitable cells such as muscle, in response to stimulation above a certain threshold. It consists of a self-propagating depolarization of 0.1 V in the cell membrane and carries an informational signal from the cell body to the nerve terminals, where it activates synaptic transmission.
A nerve impulse; a traveling wave of positive voltage that is propagated along a neuron.
The localized reversal and then restoration of electrical potential between the inside and the outside of a neuron or muscle cell
This is a membrane potential which induces the cell to perform an action. An example is a nerve cell. When it receives a stimulus, it responds by generating an electrical impulse which travels down the nerve cell and effects a response on the following cell. Close this window
Brief period of membrane depolarization, reflecting altered ionic permeability, with a fixed amplitude that propagates itself along nerve or muscle fibres.
is an all-or-nothing phenomenon and represents the basic electrical signal of the neuron. It is initiated at the initial segment of the axon hillock of the neuron and is propagated down the axon to the presynaptic terminals. It is typically in the order of 100 mV in amplitude
Spike; Transient, all-or-none reversal of membrane potential that sweeps along the membrane of a nerve or muscle cell. When stimulated the cell membrane changes conductances for various ions. Sodium ions rush in and the electrical charge across the membrane becomes positive. Local membrane depolarization stimulates the neighboring region to depolarize and then returns to its resting state; Synonyms: Spike; Related Terms: Resting Membrane Potential
the local voltage change across the cell wall as a nerve impulse is transmitted
a change of voltage within the axon
an abrupt pulse-like change in the positive-negative charge differential on either side of the nerve cell membrane
an all-or-none change in membrane potential All cells have membrane potential, but ONLY neurons and muscle cells have ability to generate changes in their membrane potential
an electrical change across a cell
an electrical charge propagated through a neuron which causes that neuron to become stimulated
an electric tension at the receptor, which arises from an electrolyte displacement between interior and exterior of the cell
a rapid change in the membrane potential of a biological neuron, induced by depolarization of the neuron above its threshold potential
a rapid reversal in the membrane potential
a rapid swing in the polarity of the membrane potential from negative to positive and back, the entire cycle lasting a few milliseconds
a rapid, transient, self-propagating electrical excitation of the membrane of electrically excitable cells, also known as a spike or nerve impulse (in neurons)
a sudden change in the transmembrane potential propagated along the length of the axon
a temporary reversal of the electrical potential along the membrane for a few milliseconds
a temporary reversal of the polarity across the membrane of a muscle cell or nerve fiber
a unidirectional wave of depolarization of the plasma membrane of neurons
a very rapid change in membrane potentialthatoccurs when a nerve cell membrane is stimulated
a wave of charge that travels along nerve cells through the body
a wave of electrical signals that is propagated rapidly and transiently along the plasma membrane of excitable cells such as neurons and some muscle and endocrine cells
a change in the permeability of the neuron membrane allowing for a change in electric potential
The electrical signal which rapidly propagates along the axon of nerve cells as well as over the surface of some muscle and glandular cells. It is the result of a change in membrane electrical potential, the underlying cause of which is a change in flow of ions across the membrane due to voltage-activated ion channels.
(also known as spike or impule) a rapid change in membrane voltage ("potential") from negative (-70 mV in nerve cells) to positive and then back to negative. This causes an electrical current that proceeds down an axon.
the potential difference in electric charge between the inside and outside of the neuron.
An electrochemical change that occurs across the cell membrane of a neuron. 611
the firing of a neuron when depolarization causes a change in the rate of entry of Na+ to the interior of a cell.
A brief, regenerative, all-or-nothing electrical potential that propagates along an axon.
Rapid, transient, all-or-none electrical activity that is propagated in the plasma membrane of excitable cells such as neurons and muscle cells. Action potentials, or nerve impulses, allow long-distance signaling in the nervous system. ( Figure 21-14)
The electrical part of a neuron's two-part, electrical-chemical message. An action potential consists of a brief pulse of electrical current that travels along the axon to relay messages over long distances.
Rapid, transient, self-propagating electrical excitation in the plasma membrane of a cell such as a neuron or muscle cell. Action potentials, or nerve impulses, allow long-distance signaling in the nerveous system.
A reversal of the electrical potential in the plasma membrane of a neuron that occurs when a nerve cell is stimulated; caused by rapid changes in membrane permeability to sodium and potassium.
The brief, all-or-nothing change in membrane potential that constitutes a single response in a neurone.
A type of neuron output signal which does not lose strength over long distances. Commonly called "nerve impulse", and when an action potential occurs, the neuron is often said to "fire an impulse".
The electrical signal which neurons transmit along their axons.
This is an electrical charge that travels down the axon of a neuron to the synaptic terminal where it can increase or decrease the probability that hundreds of intracellular vesicles filled with neurotransmitter will fuse with the pre-synaptic membrane of that neuron and release the neurotransmitter into the synaptic cleft. The action potential occurs when the neuron has been activated and temporarily reverses the electric polarity of the interior membrane from negative to positive.
This occurs when a neuron is activated and temporarily reverses the electrical state of its interior membrane from negative to positive. This electrical charge travels along the axon to the neuron's terminal where it triggers or inhibits the release of a neurotransmitter and then disappears.
the electrical signals by which information is transmitted within neurons.
The electrical activity developed n a muscle or nerve cell curing activity; a neural impulse.
An action potential is the result of a brief, localized change in the resting membrane potential. When this change of resting potential is measured it can be visualized on an oscilloscope. Action potentials are sometimes referred to as spikes or spike potentials.
a brief fluctuation in membrane potential caused by the rapid opening and closing of voltage-gated ion channels. Action potentials sweep like a wave along axons to transfer information from one place to another in the nervous system.
A brief change in the electrical potential of an axon, which is the physical basis of the nervous impulse.
An all-or-none membrane depolarization propagated along a nerve fiber without loss of amplitude.
(nerve impulse) transient all or none reversal of a membrane potential produced by regenerative inward currents in excitable membranes
Electrical "all-or-none" impulse that transmits information within the nervous system.
The electrical part of a neuron's two-part, electrical-chemical message. An action potential consists of a brief pulse of electrical current that travels along the axon. When the action potential reaches the axon terminal, it triggers neurotransmitter release.
A conducted change in the transmembrane potential of excitable cells, initiated by a change in the membrane permeability to sodium ions; see also nerve impulse.
As the traveling signals of nerves and as the localized changes that contract muscle cells, action potentials are an essential feature of animal life. They set the pace of thought and action, may constrain the sizes of evolving anatomies and enable centralized control and coordination of organs and tissues. Non-propagating action potentials occur also in some plants.
a change in electrical charge on the cell membrane that activates nerves to transmit impulses to muscles.
An action potential is a wave of electrical discharge that travels along the membrane of a cell. Action potentials are an essential feature of animal life, rapidly carrying information within and between tissues. They are also exhibited by some plants.