Discuss Cellular and Molecular Neuroscience.
This fact sheet will explain the role and use of action potential in the field of physiological science.
The fact sheet provides insight into action potential and how it functions in cell to cell communication.
Its functions are well-described. They play a significant role in muscle contraction and movement.
The fact sheet includes information about the recovery process after an action potent and the consequences for manipulation.
An action potential is a phenomenon that occurs in the membrane a nerve cells or muscle cells and leads to the reverse of electric polarization.
A neuron’s action potential moves down the axon, changing the membrane’s polarity.
This causes the Na+/K+ gated ion channel to open.
The threshold potential triggers the closing of this gate.
The action potential’s initiation is caused by depolarization, which results from the transport of Na+ions into the axon.
Repolarization happens when the K+ channels opens and moves outside of the axon.
Because of this change in polarity, impulse travels down from axon into other neurons (1).
Action potential serves the main purpose of engaging in cell-to-cell communication through transmission of signals from axons terminals to other neurons.
It activates intracellular processes in muscle cell cells.
An example of this is the action potential, which causes contraction of muscle cell.
Action potential occurs when positively charged ions travel inside the neural membrane, while negatively charged ions are released.
The positive charge increases, which results in the creation of an electric impulse. This impulse is then transmitted to the nerve.
It is responsible for the contraction of muscle cells that allows movement (2).
This is evident from the explanation of the function of action potential. The main participants in the process are potassium and the sodium ion channels.
Each channel plays a role in each stage of action potential (depolarization, depolarization, and repolarization) (3).
Below are details about each stage as well as the involvement of both channels.
During an action potential, neurotransmitters or sensory receivers stimulate the cell’s membrane.
The membrane slowly moves towards the negative polarization phase as sodium molecules diffuse into this area of the cell.
Finally, the potential reaches the threshold potential and the calcium ions are opened.
Following this, depolarization occurs so that the impulse moves. This takes place in different parts of the membrane.
Characteristics related to its Function
Action potential’s main features are related to depolarization of cells due to transmit signals.
Its function also reflects communication characteristics, as the generation of an electrical impulse during action potential acts as a form for communication between the sensory receptors and muscles.
Action potential does not contain a strong or weak signal.
It reaches either the threshold value (or the resting potentia (4).
There are three levels of action potential.
Depolarization stage – This is when the neuron’s resting potential is restored due to a high concentration of both positive and negative ions.
Positive sodium ions flow inside the cell to reverse the polarity and cause depolarization.
Repolarization stage: Once the electric gradient reaches its threshold value, both the Na+- and K+ gates open and positive charged potassium Ions emerge from the neuron.
The negative membrane potential is then restored.
Refractory Phase- This phase occurs during an action potential. The sodium gate can only open when the membrane has been repolarized to the resting potential.
This means that another action potential is not possible in this stage (5).
Recovery after an Action Potential
The refractory phase is the time after an action potential has occurred in a neuron. It is the time in which no other action potential can occur.
A cell cannot perform a similar act again after the refractory time.
It refers to the amount of time that is required to trigger a second stimulus after the excitable membrane returns from its resting phase.
During this time, the potassium channel is opened again and the salt channel is closed (6).
Thus, the neuron is able to return to its resting potential.
A second action potential in the cell is possible after this recovery.
Sometimes, the action potential can be manipulated to achieve a desired motor action from a particular muscle.
To achieve the desired result, it is possible to manipulate the extra-cellular potassium and sodium ions.
Manipulation may also be used to stimulate the opening of the cardiac Calcium channel early.
This increases the contraction force.
Molecular technology has also allowed the cloning gene for different channels.
This experimental manipulation of the channels allowed for the expression of genes.
Researchers were able identify the function properties and voltage sensitivities of different channels, as well as the kinetics of cellular interactions, easily (7).
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