Action Potential and Neurotransmission

These flashcards cover key concepts related to the action potential and neurotransmission process in neurons, focusing on definitions and mechanisms involved.

Resting Potential

The membrane potential of a neuron when it is not transmitting a signal, typically around -70 millivolts.

Action Potential

A rapid change in membrane potential that propagates along the axon, consisting of depolarization and repolarization phases.

Depolarization

The process that makes the membrane potential less negative (more positive) than the resting potential.

Threshold Potential

The membrane potential at which an action potential is initiated, approximately -55 millivolts.

Repolarization

The process of returning the membrane potential back to resting potential after an action potential, often overshooting to hyperpolarization.

Hyperpolarization

The phase following repolarization where the membrane potential becomes more negative than the resting potential.

Neurotransmitters

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

Excitatory Neurotransmitters

Neurotransmitters that promote the generation of an action potential in the postsynaptic neuron.

Inhibitory Neurotransmitters

Neurotransmitters that decrease the likelihood of generating an action potential in the postsynaptic neuron.

Saltatory Conduction

The process by which action potentials jump from one Node of Ranvier to the next along myelinated axons, increasing the speed of transmission.

Calcium Channels

Voltage-gated channels that open upon reaching the axon terminal, allowing calcium ions to enter and trigger neurotransmitter release.

Presynaptic and Postsynaptic Neurons

Presynaptic neurons send the signal by releasing neurotransmitters, while postsynaptic neurons receive the signal through receptor binding.