MT1: Action Potential

The difference in electrical charge between the inside and outside of a neuron when it is at rest, typically around -70 millivolts (mV). This is maintained by the slow leakage of potassium (K+) ions out of the cell, leaving negative anions behind.

A rapid, short-lasting change in the membrane potential of a neuron, typically lasting 2-4 milliseconds. It involves a rapid depolarization (becoming more positive) followed by repolarization (returning to the negative resting potential).

The process of the neuron becoming more positive inside, moving away from its resting potential (-70 mV). This is triggered by an influx of sodium (Na+) ions into the cell.

The process of the neuron returning to its resting potential (-70 mV) after depolarization. This is mainly caused by the outflow of potassium (K+) ions through delayed rectifier channels.

Temporary changes in the membrane potential of a neuron that can vary in voltage and duration. They are generated by stimuli and can trigger an action potential if they are strong enough.

A brief period after an action potential when the neuron is less excitable or unable to generate another action potential. This is caused by the inactivation of sodium channels and the increased permeability to potassium ions.

The specific membrane potential at which the inward and outward fluxes of a particular ion are equal, determined by the balance of diffusion and electrical forces.

The electrical potential difference across a membrane that would be reached if the membrane were permeable only to that particular ion. For instance, the equilibrium potential for potassium (K+) is around -90 mV.

The difference in electrical charge across the membrane that would be reached if the membrane were permeable only to sodium (Na+) ions, typically around +55 mV.

The electrical potential difference across the membrane that would be reached if the membrane were permeable only to potassium (K+) ions, typically around -90 mV.

The electrical potential difference across the membrane that would be reached if the membrane were permeable only to calcium (Ca2+) ions, typically around +123 mV.

The electrical potential difference across the membrane that would be reached if the membrane were permeable only to chloride (Cl-) ions, typically around -40 mV (or -65 mV depending on the cell type).

A change in the resting membrane potential (RMP) that makes the cell more negative (further away from zero). This can be caused by factors like increased permeability to potassium.

A change in the resting membrane potential (RMP) that makes the cell less negative (closer to zero). This can be caused by factors like increased permeability to sodium.

The process of an action potential traveling down the axon of a neuron. This is facilitated by the opening and closing of ion channels, creating a wave of depolarization that travels along the axon.

The rate at which an action potential travels down the axon of a neuron. This is influenced by factors like the axon's diameter and whether it is myelinated.

A type of neuron that controls skeletal muscle contraction. It has a large diameter and is myelinated, leading to a high conduction velocity (up to 100 m/s).

A type of neuron that transmits pain signals. It has a small diameter and is unmyelinated, leading to a slow conduction velocity (around 1 m/s).

A substance that can block the transmission of nerve impulses by interfering with the function of sodium channels. This can reduce local excitability, raising the threshold for action potentials.

A type of local anesthetic that works by blocking sodium channels. This reduces excitability and raises the threshold for action potentials.

A measure of the speed at which an action potential travels down the axon. It is often used to investigate motor weakness or detect pathological changes in the nervous system.

A condition that affects the transmission of nerve impulses, often characterized by conduction block or slowing. This can be detected by measuring conduction velocity.

The process of a neuron becoming more negative, further away from zero. This is usually caused by an outflow of positive ions or influx of negative ions.

The process of a neuron becoming less negative, closer to zero. This is usually caused by an influx of positive ions or outflow of negative ions.

The minimum amount of depolarization needed to trigger an action potential in a neuron. This is usually a specific voltage threshold, typically around -55 mV.

The process of a neuron firing an action potential. This is triggered when the neuron's membrane potential crosses the threshold.

The process of a neuron returning to its resting membrane potential after an action potential. This is primarily caused by the repolarization phase, involving the outflow of potassium ions.

The movement of ions across a neuron's membrane due to the difference in electrical potential on either side of the membrane. This is a key factor driving the action potential.