depolarization
Membrane potential reduction
Depolarization is a reduction or reversal of electrical polarity across a cell membrane.
In neurons and muscle cells, depolarization triggers action potentials—the electrical impulses that enable nerve signals and muscle contractions.
The term extends to any neutralizing of opposing charges or positions: The candidate's speech aimed at depolarization of the electorate.
Neuron's rapid electrical discharge
- potassium channelsMembrane proteins selective for K⁺
- nerve impulseElectrical signal through neurons
- axonNeuron's signal-sending projection
- synapseNerve signal crossing point
neurotransmitter · threshold · repolarization · hyperpolarization · excitability · myelin sheath · neuron firing · refractory period
What initiates action
- thresholdPoint of beginning
- excitationStimulation of response
- activationSetting into operation
- stimulusWhat prompts a reaction
response · firing · initiation · onset · signal · sensory transduction
Outer layer of cytoplasm
- concentration gradientDifference in solute density
- permeabilityAbility to transmit fluids
- gatingControlling access selectively
- electrochemicalInvolving electricity and chemistry
Tissue powering circulation
- electrocardiogramHeart's electrical activity record
- contractionReduction in size
- calcium influxIons flowing into cytoplasm
- cardiac cycleOne complete heart contraction-relaxation
arrhythmia · fibrillation · heartbeat · systole · defibrillation
action potential
Neuron's rapid electrical discharge
- potassium channelsMembrane proteins selective for K⁺
- nerve impulseElectrical signal through neurons
- axonNeuron's signal-sending projection
synapse · neurotransmitter · threshold · repolarization · hyperpolarization · excitability · myelin sheath · neuron firing · refractory period · dendrite
trigger
What initiates action
- thresholdPoint of beginning
- excitationStimulation of response
- activationSetting into operation
stimulus · response · firing · initiation · onset · signal · sensory transduction
cell membrane
Outer layer of cytoplasm
- concentration gradientDifference in solute density
- permeabilityAbility to transmit fluids
- gatingControlling access selectively
heart muscle
Tissue powering circulation
- electrocardiogramHeart's electrical activity record
- contractionReduction in size
- calcium influxIons flowing into cytoplasm
cardiac cycle · arrhythmia · fibrillation · heartbeat · systole · defibrillation
- neuroscienceneuron, MRI, brain, neurons, synapses
- polarizationpolarizer, divide, polarized light, divisiveness, polarizing filter
- ECGECG, EKG, electrodes, leads, waveform
- electrophysiologyaction potential, electrodes, EEG, EMG, ECG
- Neurophysiologyneuron, action potential, neurotransmitter, nerve impulse, presynaptic
- bioelectricityaction potential, repolarization, hyperpolarization, axon, voltage-gated
depolarizationpolarization
Separation into opposing extremes
political polarization · division · fragmentation · radicalization · factionalism
polar, polarization, polarity, polarize, bipolarity, depolarize, depolarized, multipolarity, depolarizing