Neuroscience: Graded Membrane Potential

A long extension of a neuron that conducts electrical signals away from the cell body.

The specialized region of the axon where the action potential is initiated.

The terminal portion of the axon responsible for releasing neurotransmitters into the synapse.

The movement of materials within a neuron, including transport of vesicles, proteins, and organelles.

A fatty substance that insulates the axon and increases the speed of signal conduction.

Gaps in the myelin sheath that facilitate rapid saltatory conduction of action potentials.

A disorder characterized by degeneration of the myelin sheath in the central nervous system.

A disorder that affects the peripheral nervous system with destruction of myelin sheath causing muscle weakness and tingling sensations.

The difference in electrical potential across a cell membrane, caused by the unequal distribution of ions. It represents the energy stored across the membrane.

The theoretical electrical potential difference across a membrane that would be required to prevent the movement of an ion down its concentration gradient.

The charge difference across the cell membrane when the cell is not actively signaling. It is usually negative inside the cell compared to the outside.

The movement of ions across a membrane driven by both the concentration gradient and the electrical potential difference.

The Nernst equation is a mathematical formula used to calculate the equilibrium potential for a single ion across a membrane.

The movement of ions across a membrane due to their different concentrations inside and outside the cell.

The movement of ions across a membrane due to the electrical potential difference across the membrane.

A specialized pipette used to measure the electrical potential difference across a cell membrane.

The difference in electrical charge between the inside and outside of a cell membrane when the cell is at rest.

The movement of ions across the cell membrane due to differences in concentration and electrical charge.

The difference in permeability of the cell membrane to different ions. For example, the membrane is more permeable to potassium ions (K+) than sodium ions (Na+).

The active transport of sodium (Na+) and potassium (K+) ions across the cell membrane, creating an electrochemical gradient.

Proteins embedded in the cell membrane that allow ions to pass through.

Ion channels that are always open, allowing a continuous flow of ions.

Ion channels that open or close in response to a specific stimulus, such as a change in voltage or binding of a chemical.

The process of opening and closing gated ion channels, which allows for the rapid transmission of signals in the nervous system and other cells.

A localized and temporary change in membrane potential that can vary in magnitude depending on the strength of the stimulus. It spreads passively, with attenuation and decay, and can summate to reach a threshold for further action.

A change in membrane potential that makes the inside of the cell more positive, bringing it closer to the threshold for an action potential.

A change in membrane potential that makes the inside of the cell more negative, moving it further away from the threshold for an action potential.

GMPs can be summed together, meaning that multiple stimuli close in time or space can add up to create a larger change in membrane potential.

GMPs lack a threshold, meaning that they can occur even with small stimuli. Unlike action potentials, they do not have a specific level of depolarization required for their initiation.

A change in membrane potential that is proportional to the strength of the stimulus. It can be either depolarizing or hyperpolarizing and decays over distance.

The region of a neuron where an action potential is initiated. It is typically located at the axon hillock.

The minimum amount of depolarization required to trigger an action potential. This is the threshold voltage.

A period following an action potential during which the neuron cannot generate another action potential. This ensures that action potentials are not transmitted back towards the cell body.

The process by which a neuron generates an action potential, involving sequential influx of Na+ ions followed by efflux of K+ ions.

The rising phase of an action potential, characterized by rapid depolarization due to influx of Na+ ions.

The falling phase of an action potential, characterized by repolarization due to efflux of K+ ions.

The state of the neuronal membrane after an action potential has occurred. The membrane potential returns to its resting value.

Nerve fibers with a diameter less than 2 micrometers and lacking myelin sheath. They conduct impulses at a slow rate of 1 meter per second and transmit autonomic motor and visceral sensory information.

The process by which an action potential (AP) travels along a nerve fiber only in one direction, from the axon hillock towards the axon terminal.

A junction between two neurons where communication occurs through the release of chemical messengers called neurotransmitters. These junctions are composed of a presynaptic neuron that releases the neurotransmitter, a synaptic cleft, and a postsynaptic neuron that receives the neurotransmitter.

The terminal part of the axon that contains vesicles filled with neurotransmitters. These vesicles release neurotransmitters into the synaptic cleft when an action potential arrives.

A neuron that receives the neurotransmitter released by the presynaptic neuron. It has receptors that bind to the neurotransmitter, triggering a response.

The space between the presynaptic and postsynaptic neuron. This space allows for the diffusion of the neurotransmitter from the presynaptic neuron to the postsynaptic neuron.

A type of synapse where the axon terminal of one neuron forms a junction with the dendrite of another neuron.

A type of synapse formed between the axon terminal of one neuron and the soma (cell body) of another neuron.