Nerve Impulse Conduction and Neuron Physiology

This set of flashcards covers important vocabulary related to nerve impulse conduction, neuronal structure, and function.

Nodes of Ranvier

Gaps in the myelin sheath between adjacent Schwann cells or oligodendrocytes that facilitate rapid nerve impulse conduction.

Myelin sheath

An insulating layer around axons that increases the speed of conduction of nerve impulses.

Gray matter

Regions of the nervous system rich in neuronal cell bodies, appearing gray due to the absence of myelin.

White matter

Regions of the nervous system rich in myelinated axons, appearing white due to the presence of myelin.

Axon hillock

The area of the neuron where the axon begins and where action potentials are initiated.

Resting membrane potential

The voltage difference across the membrane of a resting neuron, typically around -70 mV.

Action potential

A rapid reversal of membrane potential that propagates along the axon, resulting in nerve impulse conduction.

Graded potential

A small, localized change in membrane potential that can lead to an action potential if a threshold is reached.

Saltatory conduction

The process of action potentials jumping from one node of Ranvier to the next in myelinated axons, increasing conduction speed.

Continuous conduction

The process by which action potentials propagate along unmyelinated axons, segment by segment.

Voltage-gated sodium channels

Protein channels in the neuronal membrane that open in response to depolarization, allowing sodium ions to enter the cell.

Ligand-gated ion channels

Protein channels that open in response to the binding of a specific chemical or neurotransmitter.

Refractory period

A brief period after an action potential during which a neuron cannot generate another action potential.

Synapse

The junction between two neurons, or between a neuron and another cell, where signals are transmitted.

Presynaptic neuron

The neuron that sends the signal at a synapse.

Postsynaptic neuron

The neuron that receives the signal at a synapse.

Calcium influx

The entry of calcium ions into the presynaptic terminal that triggers the release of neurotransmitters.

Neurotransmitter

Chemicals released by neurons that transmit signals across synapses to other neurons or target cells.