Neurotransmitters and Action Potentials

Flashcards covering key concepts and vocabulary related to neurotransmitters and action potential mechanisms.

Neurotransmitter

A chemical messenger that transmits signals across a synapse from one neuron to another.

Excitatory Postsynaptic Potential (EPSP)

A temporary increase in postsynaptic membrane potential that makes it more likely to generate an action potential.

Graded Potential

A localized change in membrane potential that varies in size and can summate, but does not always lead to action potential.

Threshold Potential

The critical level to which a membrane potential must be depolarized to initiate an action potential.

Reuptake Pump

A protein that transports neurotransmitters from the synaptic cleft back into the presynaptic neuron.

Synaptic Cleft

The small gap between the presynaptic and postsynaptic membranes where neurotransmitters diffuse.

Calcium Voltage-Gated Channels

Channels that open in response to depolarization, allowing calcium ions to enter the cell and trigger exocytosis.

SNARE Proteins

Proteins that mediate the fusion of transport vesicles with their target membranes.

Exocytosis

The process by which neurotransmitters are released from vesicles into the synaptic cleft.

Absolute Refractory Period

The time during which a second action potential cannot occur, no matter how strong a stimulus is applied.

Relative Refractory Period

The period following an action potential during which the neuron is less sensitive to stimuli and requires a larger than normal stimulus to initiate a new action potential.

Myelination

The process of forming a myelin sheath around a nerve to increase conduction velocity.

Hyperpolarization

An increase in a cell's membrane potential, making it more negative and less likely to generate an action potential.

Hypokalemia

A condition characterized by abnormally low levels of potassium in the extracellular fluid, which can affect muscle contraction.

Hyperkalemia

A condition characterized by abnormally high levels of potassium in the extracellular fluid, leading to increased excitability of cells.

Acetylcholine

A neurotransmitter that plays a role in muscle contraction, neurotransmission, and regulating heart rate.

Second Messenger System

A process whereby a neurotransmitter binds to a receptor and activates a series of intracellular signaling events, leading to a cellular response.