Lesson 9 Vocab

VT Biol 1106

Acetylcholine

A neurotransmitter that plays a key role in the communication between neurons in both the central and peripheral nervous systems.

Action Potential

A rapid rise and fall in membrane potential that occurs when a neuron fires, allowing the transmission of signals along the axon.

Axon terminal

The endpoint of a neuron where neurotransmitters are released to communicate with the postsynaptic cells.

Chemically gated ion channels

Ion channels that open in response to the binding of neurotransmitter molecules, leading to changes in the membrane potential.

Depolarization

The process by which the membrane potential becomes less negative (more positive) as sodium ions enter the neuron, leading to an action potential.

Dopamine

A neurotransmitter involved in reward and pleasure pathways that mediates communication between neurons related to mood and motivation.

Endorphins

Neurotransmitters that help relieve pain and induce feelings of pleasure or euphoria in communication between neurons.

Excitatory neurotransmitter

A type of neurotransmitter that promotes depolarization of the postsynaptic membrane, increasing the likelihood of an action potential.

Excitatory post synaptic potential (EPSP)

A temporary increase in the postsynaptic membrane potential due to the influx of cations, making the neuron more likely to fire.

GABA

Gamma-Aminobutyric Acid, a main inhibitory neurotransmitter that decreases the likelihood of action potentials in neurons.

Gated ion channels

Channels that open or close in response to signals, controlling ion flow and thus the membrane potential in neurons.

Glutamate

The primary excitatory neurotransmitter in the brain, crucial for synaptic plasticity and communication between neurons.

Graded potential

A change in the membrane potential that varies in size and is proportional to the strength of the stimulus, influencing neuronal communication.

Habituation

A decrease in response to a stimulus after repeated exposure, affecting how neurons communicate the significance of ongoing signals.

Hyperpolarization

An increase in the negativity of the membrane potential, which decreases the likelihood of an action potential in the neuron.

Inhibitory neurotransmitters

Neurotransmitters that reduce the likelihood of an action potential by hyperpolarizing the postsynaptic membrane.

Inhibitory post synaptic potential (IPSP)

A temporary decrease in the postsynaptic membrane potential due to the influx of negatively charged ions.

Leakage channels

Ion channels that are always open, allowing ions to passively diffuse across the membrane, thus influencing the resting potential.

Ligand gated channels

Ion channels that open in response to the binding of neurotransmitters, facilitating ion flow and altering the membrane potential.

Membrane potential

The electrical potential difference across a neuron's membrane, crucial for the generation and propagation of action potentials.

Nerve impulse

An electrical signal that travels down the axon of a neuron, resulting from action potentials triggered during neuronal communication.

Neurotransmitters

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

Nicotine

A stimulant that mimics acetylcholine and affects communication between neurons by binding to acetylcholine receptors.

Postsynaptic cell

The neuron that receives the signal from a presynaptic cell through the binding of neurotransmitters.

Presynaptic cell

The neuron that releases neurotransmitters into the synaptic cleft to communicate with the postsynaptic cell.

Propagation

The process by which action potentials are transmitted along the axon and to the axon terminals.

Refractory period

The period following an action potential during which a neuron cannot fire another action potential.

Repolarization

The process of returning the membrane potential to its resting state after depolarization; essential for subsequent action potentials.

Resting potential

The difference in charge across a neuron's membrane when it is not actively sending a signal, typically around -70mV.

Saltatory conduction

The jumping of action potentials from one node of Ranvier to the next along myelinated axons, increasing transmission speed.

Serotonin

A neurotransmitter that regulates mood, appetite, and sleep; it plays a role in communication within the brain.

Sodium-potassium pump

A protein that uses ATP to move sodium out of and potassium into the neuron, crucial for maintaining the resting potential.

Spatial summation

The process by which multiple presynaptic neurons release neurotransmitters simultaneously, leading to a greater postsynaptic potential.

Summation

The cumulative effect of excitatory and inhibitory inputs on the postsynaptic neuron, determining whether it will fire an action potential.

Synapse

The junction between two neurons where communication occurs via neurotransmitters.

Synaptic cleft

The small gap between the presynaptic and postsynaptic neuron's membranes where neurotransmitters are released.

Synaptic integration

The process by which multiple synaptic inputs are combined in the postsynaptic neuron to determine action potential generation.

Synaptic terminal

The end of the axon where neurotransmitters are stored in vesicles and released into the synaptic cleft.

Synaptic vesicle

Small membrane-bound structures that contain neurotransmitters, releasing them into the synaptic cleft upon stimulation.

Temporal summation

The process by which multiple impulses from a single presynaptic neuron over time combine to influence the postsynaptic potential.

Threshold potential

The critical level of depolarization that must be reached for an action potential to occur in a neuron.

Voltage gated channels

Ion channels that open or close in response to changes in membrane potential, vital for generating action potentials.