Propagation of an Action Potential Along an Axon and Actions at the Synapse

These flashcards cover key terminology and concepts related to the propagation of action potentials and synaptic transmission as outlined in the lecture notes.

Action Potential

A rapid rise and fall in voltage across a neuron’s membrane, representing a signal transmission.

Voltage Gated Channel (VGC)

A type of ion channel that opens or closes in response to changes in membrane potential.

Saltatory Conduction

The process by which action potentials jump from one node of Ranvier to the next in myelinated axons.

Continuous Conduction

The unmyelinated propagation of an action potential along the entire length of the axon.

Refractory Periods

Periods during which a neuron cannot fire a new action potential or requires a stronger stimulus to do so.

Synapse

The junction between two neurons, where neurotransmitters are released and signals are transmitted.

Neurotransmitters

Chemical messengers that transmit signals across a synapse from one neuron to another.

Nodes of Ranvier

Gaps in the myelin sheath where voltage-gated ion channels are concentrated, allowing for saltatory conduction.

Presynaptic Neuron

The neuron that transmits an impulse toward the synapse.

Postsynaptic Neuron

The neuron that receives the impulse across the synapse.

Calcium (Ca2+) Channels

Channels that open to allow calcium ions to enter the axon terminal, triggering neurotransmitter release.

Dendrites

Branch-like extensions of a neuron that receive signals from other neurons.

Chemical Synapse

A type of synapse where neurotransmitters are released to transmit signals.

Multiple Sclerosis

A disease where the myelin sheath deteriorates, affecting nerve impulse transmission.

Axon Hillock

The part of the neuron where the axon begins, often involved in action potential initiation.

Repolarization

The process of restoring the membrane potential to its resting state after an action potential.

Hyperpolarization

A change in a neuron’s membrane potential that makes it more negative than the resting potential.

Synaptic Cleft

The space between the presynaptic and postsynaptic membranes at the synapse.