Module 1.2 Vocab Flashcards
Absolute Refractory Period
A time when the membrane is unable to produce an action potential
Action Potentials
All-or-non message sent by an axon
All-or-none law
Principle that the amplitude and velocity of an action potential are independent of the stimulus that initiated it
concentration gradient
difference in distribution of the ions across the neuron’s membrane
depolarize
(Depolarization) to reduce polarization toward zero across a membrane
electrical gradient
Difference in electrical charges between the inside and outside of the cell
Graded Potential
A membrane potential that varies in magnitude in proportion to the intensity of the stimulus
Hyperpolarization
Increased polarization across a membrane
Local Anesthetic
Drug that attaches to the sodium channels of the membrane, stopping action potentials
Local Neurons
Neurons without an axon
Myelin
An insulating material composed of fats and proteins
Myelinated Axons
Axons covered with myelin sheaths
Polarization
Difference in electrical charges between the inside and outside of the cell
Propagation of the Action Potential
transmission of an action potential down an axon
Refractory Period
Time when the cell resists the production of further action potentials
Relative Refractory Period
Time after the absolute refractory period that requires a stronger stimulus to initiate an action potential
Resting Potential
Condition of a neuron’s membrane when it has not been stimulated or inhibited
Saltatory Conduction
The jumping of action potentials from node to node
Selective permeability
Ability of some chemicals to pass more freely than others through a membrane
Sodium-Potassium pump
Mechanism that actively transports sodium ions out of the cell while drawing in two potassium ions
Threshold
Minimum amount of membrane depolarization necessary to trigger an action potential
Voltage-gated channels
Membrane channel whose permeability to sodium (or some other ion) depends on the voltage difference across the membrane
