The Nerve Impulse

Psychology 2200 with Brunjes at University of Virginia

About this deck

By: Camerron Resener
Created: 2011-07-29
Size: 23 flashcards
Views: 10

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Absolute refractory period

Time immediately after an action potential, when the sodium gates close and the membrane cannot produce an action potential in response to stimulation of any intensity

Action potential

Rapid depolarization and slight reversal of the usual polarization caused by stimulation beyond the threshold

All-or-none law

Principle stating that the size, amplitude, and velocity of the action potential are independent of the intensity of the stimulus that initiated it

Axon hillock

Swelling of the soma, the point where the axon begins

Concentration gradient

Difference in distribution of ions across a membrane

Depolarize

Reduction in the level of polarization across a membrane

Electrical gradient

Difference in positive and negative charges across a membrane

Graded potentials

Membrane potential that varies in magnitude and does not follow the all-or-none law

Hyperpolarization

Increased polarization across a membrane

Local anesthetic

Drug that attaches to the sodium channels of the membrane, preventing sodium ions from entering and thereby blocking action potentials

Local neurons

Small neuron with no axon or a very short one

Myelin

Insulating material composed of fats and proteins

Myelinated axons

Axon covered with a myelin sheath

Polarization

Electrical gradient across a membrane

Propagation of the action potential

Transmission of an action potential down an axon

Refractory period

Brief period following an action potential, when the cell resists the production of further action potentials

Relative refractory period

Time after the absolute refractory period, when potassium gates remain open wider than usual, requiring a stronger than usual stimulus to initiate an action potential

Resting potential

Electrical potential across a membrane wen a neuron is not being stimulated

Saltatory conduction

Jumping of action potentials from one node to another by the flow of positive ions

Selectively permeable

Ability of certain chemicals to pass more freely than others through a membrane

Sodium-potassium pump

Mechanism that actively transports three sodium ions out of the cell while simultaneously drawing in two potassium ions

Threshold of excitation

Level of depolarization at which a brief stimulation triggers a rapid, massive electrical change by the membrane

Voltage-gated channels

Membrane channel whose permeability to sodium (or some other ion) depends on the voltage difference across the membrane

About this deck

By: Camerron Resener
Created: 2011-07-29
Size: 23 flashcards
Views: 10

About StudyBlue

“Simply amazing. The flash cards are smooth, there are many different types of studying tools, and there is a great search engine. I praise you on the awesomeness.”
Dennis