Local/graded potential

Wikis > Neurology > Neurophysiology > Local/graded potential

Local/graded potential:
disturbance in membrane potential when neuron is stimulated (either chemical, light, heat or mechanical) – do not travel for more than 1 or 2 mm
result from chemical (eg pain substance) binding to receptors (ligand regulated sodium gates) that lead to inflow of Na+ into cell (neutralises internal negative charge) – becomes ‘depolarised’  produces a local or short range change in voltage  local potential
local potentials vary in size depending on strength of stimulus – they are graded (action potential are ‘all or none’ and are not graded)
local potentials get weaker the further they spread from point of stimulus (action potentials do not get weaker)
local potentials are reversible – returns quickly to its resting potential (action potentials are not reversible when threshold reached)
local potentials can be either inhibitory or excitatory

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