Question

In your own words, briefly define an action potential and a nerve impulse.Describe the following events in terms of ion movement and millivoltage: resting potential, depolarization, and threshold.

Answer 1

Nerve impulse is the process by which neurons communicate with each other by changes in their membrane potential.

These are just a electrical signal with dendrites to produce a actions potential or nerve impulse.Action potential is a result of ions moving in and out of cell these are sodium and potassium.This action potential when comes near pre-synaptic ion it causes the realise of neurotransmitters and it makes the opening of ion gated channel in post synaptic ion which works as a communication process.

Resting potential is an electrical potential of a neuron or other cell from outside of the cell when not stimulated or involved in process of impulse.

The resting potential of electrically excitable cells lies in the range of −60 to −95 millivolts (1 millivolt = 0.001 volt), with the inside of the cell negatively charged. If the inside of a cell becomes more electronegative the membrane or the cell is said to be hyperpolarized. If the inside of the cell becomes less negative the process is called depolarization.

When the sodium comes inside the cell then the positive charge increases inside the cell and makes it less negative and hence depolarised it is also helpful in communication of cell functions of cells.

When the depolarization reaches about -55 mV a neuron use to fire a action potential and this is called threshold.