Neuroscience Chapter on Neurotransmitters

Neurons are specialized cells responsible for communication within the nervous system. They carry information from one location to another.

The cell body of a neuron contains the nucleus and most of the cell's organelles. It's the control center.

Dendrites are branching extensions of a neuron that receive signals from other neurons. They're like the 'antennae' that pick up information.

The axon is a long, slender extension of a neuron that transmits signals to other cells. It acts as the 'wire' that transmits the signal.

The axon hillock is the tapered region where the axon connects to the cell body. It's the ‘decision making’ point for transmitting signals.

A synapse is a specialized junction between a neuron and another cell. It acts as the 'gap' where information is transmitted.

Neurotransmitters are chemical messengers that are released at synapses to transmit signals between neurons.

Electrochemical gradients are created by differences in ion concentration across the cell membrane. This drives the transmission of signals.

The difference in electrical charge across a cell's membrane. This allows for communication between neurons.

The membrane potential when a neuron is not actively sending signals. It's like the 'resting' state of a neuron.

Small changes in membrane potential that can vary in strength. They are short-distance signals that can be added or subtracted.

A rapid, brief change in membrane potential that travels a long distance down the neuron's axon. It's the primary way neurons communicate.

A specialized junction where a neuron communicates with another cell. It's like the 'messaging hub' where information is transmitted.

Chemical messengers released at synapses to transmit signals between neurons. They act like the 'language' neurons use to communicate.

The movement of ions across a membrane due to both concentration differences and electrical gradients. It creates the force that drives signals in neurons.

The ability of a neuron to transmit information over long distances via action potentials. It's the core function of neurons.

The resting membrane potential of a neuron is primarily determined by the permeability of the membrane to potassium ions (K+). This is because at rest, the membrane is more permeable to K+ than to other ions like sodium (Na+).

A microelectrode is used to measure the voltage difference between the inside and outside of a neuron. This measurement is crucial for understanding how neurons transmit signals.

Voltage-gated ion channels are proteins embedded in the cell membrane. They open or close in response to changes in membrane potential (voltage). This allows ions to move across the membrane, which is essential for transmitting signals.

Depolarization is a decrease in the membrane potential. It occurs when positively charged ions, like Na+, enter the cell, making the inside less negative.

Hyperpolarization is an increase in the membrane potential. It occurs when negatively charged ions, like K+, leave the cell, making the inside more negative.

The threshold is the critical level of depolarization that an action potential needs to reach in order to be triggered.

The movement of an action potential down an axon, from the axon hillock to the synaptic terminals.

A refractory period is a brief time after an action potential where the neuron is less likely to fire another action potential. This prevents the signal from traveling backwards.

The insulating layer around some axons that speeds up the transmission of action potentials. It is made of lipids, which act as poor conductors of electricity.

A type of action potential conduction in myelinated axons where the signal 'jumps' from one node of Ranvier to the next, skipping over the myelinated sections.

The small gaps between sections of myelin sheath on a myelinated axon. These gaps are where action potentials occur.

A type of synapse where electrical current flows directly from one neuron to another through gap junctions.

Voltage-gated sodium channels are responsible for the rapid depolarization phase of the action potential. If they are blocked, this phase will not occur.

A toxin that specifically blocks voltage-gated sodium channels would disrupt the rapid depolarization that drives the action potential.

A type of receptor that utilizes a metabolic cascade to alter cell activity after neurotransmitter binding.

A change in membrane potential that brings the neuron closer to firing an action potential.

A change in membrane potential that moves the neuron further away from firing an action potential.

The process of eliminating neurotransmitters from the synaptic cleft.

A potent nerve gas that inhibits the enzyme responsible for breaking down the neurotransmitter acetylcholine, leading to paralysis and death.

The arrival of an action potential at the axon terminal triggers the opening of voltage-gated calcium channels.

The neurotransmitter is packaged in synaptic vesicles, small sacs within the presynaptic terminal.

The neurotransmitter diffuses across the synaptic cleft, the small gap between the presynaptic and postsynaptic neurons.

The neurotransmitter binds to specific receptors on the postsynaptic neuron, triggering a response.

The binding of neurotransmitters to receptors can cause either excitation or inhibition of the postsynaptic neuron.

Ligand-gated ion channels are channels that open or close in response to the binding of a specific neurotransmitter.

When neurotransmitters bind to ligand-gated ion channels, they open, allowing specific ions to flow across the postsynaptic membrane.

This change in ion permeability creates a change in the membrane potential of the postsynaptic cell, generating a postsynaptic potential.