Question

Differentiate between action potential and resting potential.

Answer 1

Resting potential and action potential are activities involved in neuronal impulse conduction. These states are interconverted in order to conduct a signal. To explain it better, explain the conduction of nerve impulse.

Complete Answer:
The difference in electrical charge that exists between the inside of electrically excitable neurons and their outer environment is known as resting potential when no signal is being transmitted. At this stage, the axoplasm is negatively charged because it has more potassium ions and negatively charged proteins on the inside while high sodium ions concentration is present outside the neuron, producing a positive charge. This is maintained by active transport of sodium and potassium ions across the membrane, 3 sodium sent out exchanging 2 potassium ions towards the inside. This state is called polarized.

An action potential is generated in order to pass signals from one neuron to the next. The axonal membrane becomes permeable to sodium ions creating a potential difference creating an action potential. The axoplasm becomes positively charged and negative charge builds up outside the membrane. It is called depolarization. It is carried through the length of the neuron towards the end of the axon, this particular neuron is called pre synaptic neuron. The signal has to be passed through the gap junction, finally reaching the dendrite of the next neuron, called the postsynaptic neuron. The signal is passed as neurotransmitters present in vesicles.

s.no	Resting potential	Action potential
1	The potential difference across nerve fibre when the neuron is not conducting any signal.	It is the potential difference across nerve fibre when a nerve impulse is being conducted.
2	The permeability of membrane is more for potassium ions and nearly impermeable for sodium ions.	The membrane is more permeable to sodium ions than to potassium ions.
3	polarization	Depolarization

Note: Permeability for sodium ions in the axonal membrane is short lived, as the impulse is carried forward, the resting potential is regenerated. The reversibility of charge is responsible for transmission of impulse, to achieve it, the membrane polarity has to be changed simultaneously.