14 terms

Nervous system-Workbook terms p. 134-136

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Action potential
Impulses travelling down a nerve cell axon.
Intracellular
Inside a cell.
Refractory period
Period of repolarization during which the neuron cannot respond to a second stimulus. Period of time when all of the K+ are outside the cell and have not yet been pumped back in.
Intercellular
Located between cells.
De-polarized
Membrane potential becomes LESS NEGATIVE.
Repolarization
The stage of impulse transmission when K+ flow out of the cell. The period of change from +55mV to -75mV.
Depolarization
The beginning of this stage of impulse transmission is when the Na+ gates open. This phase of impulse transmission involves a large increase in membrane potential resulting in a sudden change from -70mV to +55mV.
Stimulus
The name of the signal that starts an action potential.
Na+
These ions cannot move across the membrane unless their gate is open. When they move into the cell, the potential becomes positive.
Polarized
The state of having a greater charge on one side than the other of a membrane.
Resting membrane potential
The normal potential of the inside of a nerve cell. When the cell's potential is at -70mV.
K+
These ions can move across the membrane even if their gate is closed. When their gates open, they rush out of the cell.
Sodium-Potassium pump
This is the machinary that re-establishes resting membrane potential, helping the nerve cell return to normal after an impulse. This pumps sodium and potassium ions across a membrane.
Glial cells
These act as a support system for neurons. Cell in the nervous system that is supportive and connective in function.