How Neurons communicate
Explain how neurons communicate. Include electric and chemical components of communication.
Neurons refer to the fundamental units of the brain and the nervous system, responsible for communication. Notably, neurons are made up of specialized parts known as Dendrites, cell bodies, and Axons, specially designed to transmit information into the synapses, thus communicating with the other cells and neurons (Woodruff, 2017). The cell body consists of the nucleus as well as other organelles that perform the vital function of the cell, while the dendrites are an extension of the cell body that receives signals. On the other hand, the axon is a long projection of the cell body that directs signals. Furthermore, neurons can be categorized into afferent and efferent neurons. Afferent signals are sensory neurons whose function is to transmit and receive stimuli, while efferent neurons are motor neurons that produce a response in the targeted cells. For instance, when the first neuron receives information, an electrical impulse is then triggered, thus releasing the chemical signal-the neurotransmitters. The neurotransmitters then move into the synapse where they bind with receptors, thus relaying the information to the second neuron.
Neurons communicate mainly through electrical and chemical signals. The electrical signals are referred to as ‘action potentials’ which relays information from one neuron to another. On the other hand, the chemical signals are neurotransmitters transmitting information from one neuron to another (Woodruff, 2017). Upon stimulation by stimuli, a neuron produces an electrical potential that travels through it. This production comprises the electrical component of neuron communication. As the electrical current approaches the axon terminal, it initiates the release of particular chemical messengers. The release of messenger chemicals, therefore, constitutes the chemical component of neuron communication. The chemical messengers (neurotransmitters) enhance the interaction between one neuron to the other (Dismukes, 1979). A synapse is a gap between the signal transmitting neuron and the signal receiving neuron.
It is important to note that an action potential triggers neurotransmitters- a rapid change in membrane potential that triggers communication impulse, which then triggers a similar ‘action potential’ in the next neuron, thereby relaying communication. When no signal is transmitted, the neurons are at a resting-potential equivalent to -70millivolts. Communication is initiated when an adjacent neuron sends a neurotransmitter. The neurotransmitter binds the neuron. In case it is excitatory, it causing the gated ion channels to open up. Opening up of the gated ion channels allows entry of sodium ions into the cell. Consequently, the cell becomes more positive. If the neurotransmitter is inhibitory, the gated ion channels open to release potassium ions from the cell. As a result, the potential of the cell becomes more negative. An action potential is generated when there are enough excitatory transmitters that can surpass the threshold level. Upon exceeding the threshold level, an electrical potential is transmitted along the axon. This process is referred to as depolarization. Depolarization is followed by the reestablishment of the resting potential by the neuron’s ion pumps. In this process, the neuron gets into a refractory period, characterized by zero action potential. This condition is referred to as hyperpolarization. Restoration of the potential prepares the neuron for a new stimulus (Yuste et al., 2011). In a nutshell, neurotransmitters play a pivotal role as far as communication between neurons is concerned.
References
Dismukes, R. K. (1979). New concepts of molecular communication among neurons. Behavioral and Brain Sciences, 2(3), 409-416.
Peterka, D. S., Takahashi, H., & Yuste, R. (2011). Imaging voltage in neurons. Neuron, 69(1), 9-21.
Woodruff, A. (2017). Action potentials and synapses. Queensland Brain Institute – University of
Queensland. https://qbi.uq.edu.au/brain-basics/brain/brain-physiology/action-potentials
and-synapses