Neurophysiology Flashcards

Electrochemical gradients

Differences in ion distribution across a cell membrane

Equilibrium potential

The membrane potential at which there is no net flux of an ion

Nernst equation

A mathematical equation used to calculate the equilibrium potential for an ion

Electrochemical disequilibrium

A state in which there is a difference in ion concentrations across a cell membrane

Active transport

The movement of ions against their concentration gradient

Channel-mediated diffusion

The movement of ions down their concentration gradient through ion channels

Initial Conditions

The starting concentrations of ions before any movement occurs

At Equilibrium

The state in which there is no net movement of ions

Equilibrium potential

The membrane potential at which there is no net flux of an ion

Calculating equilibrium potentials

Using the Nernst equation to determine the equilibrium potential for an ion species

Important notes on electrochemical gradients

Key points about the distribution of ions across a cell membrane

Cells exist in a steady state

Cells are in a state of equilibrium maintained by active transport mechanisms

Resting membrane potentials

The membrane potential of a cell at rest

Measuring membrane potential

Comparing the net charge inside the cell to the net charge outside to measure the membrane potential

Resting membrane potential

The sum of electrical gradients for all ions permeable to the membrane when the cell is at steady state

Action potentials

Electrical signals of uniform strength that travel along the axon

Capacitance

The ability of the cell membrane to store and utilize separated charge differences

Local current spread

The spread of charge along the length of the axon

Action potential propagation

The transmission of action potentials along the length of an axon

Blocking ion channels

Preventing the flow of current through specific ion channels

Saltatory action potential propagation

The jumping of action potentials from node to node along a myelinated axon

Demyelinating disorders

Conditions in which the myelin sheath is damaged or lost

Types of neuron

Different classifications of neurons based on function, fiber diameter, myelination, and conduction velocity

Synapses

Junctions between two neurons where information is transmitted

Electrical synapses

Synapses that permit direct flow of current between two neurons

Chemical synapses

Synapses that rely on the release and binding of neurotransmitters

Neuromuscular junction

The synapse between a motor neuron and a muscle fiber

Neurotransmitter release

The process by which neurotransmitters are released from the presynaptic neuron

Synaptic vesicle cycling

The recycling of synaptic vesicles after neurotransmitter release

Encoding signal strength

The representation of stimulus strength through the frequency of action potential firing

Synaptic timing

The precise timing of action potentials and neurotransmitter release

Neurotransmitter binding

The interaction between neurotransmitters and their receptors