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Glossary of Physiology Terms – U
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Undershoot
Definition:
Refers to the hyperpolarization phase of the action potential.

It is also referred to as hyperpolarizing afterpotential.

See figure.

Related glossary terms/phrases:
Hyperpolarization

See also:
Important Features of the Neuronal Action Potential



Unidirectional flux
Definition:
The rate of movement of a substance across an interface in only one, and not the opposite, direction (i.e., flux in only one direction). For example, when referring to the plasma membrane of cells, we can think of unidirectional flux of a substance ino the cell (referred to as influx), as well as unidirectional flux of the substance out of the cell (referred to as efflux). The difference between two unidirectional fluxes is referred to as net flux, which is the net amount that moves into or out of the cell.

Related glossary terms/phrases:
Flux
Influx
Efflux
Net flux









Posted: Saturday, March 30, 2013
Last updated: Friday, January 16, 2015