What are the dendrites of neurons?

The different parts of neurons tell us a lot about how these little cells work. of the brain.

The neural axonsFor example, with their elongated wire-like shape they allow electricity to travel through them, regardless of whether or not they are accompanied by myelin sheaths. The dendrites, in turn, fulfill another function that we will see now.

What are dendrites and what is their function?

Dendrites are parts of neurons that are found throughout the body, that is, both in the brain and spinal cord and in those that are in the ganglia, internal organs, muscles, etc.

Specifically, dendrites are small branches that come out of the cell body (the part of the neuron where the cell nucleus is located). Compared to the axon, the dendrites are usually shorter and thinner, so that they end closer to the cell body.

What's more, on the surface of the dendrites there is still another class of prolongations microscopic. These are small formations called dendritic spines, which are, in turn, the places where the dendrites fulfill their main function, as we will see.

Dendritic spines and synapses

Since the time of the famous Spanish neurologist Santiago Ramón y Cajal, it has been known that neurons are relatively independent small bodies, that is, that there is a separation between them. A part of this space that separates neurons from each other are the so-called synaptic spaces, which are the points through which these nerve cells pass information through substances called neurotransmitters.

The function of dendrites in general, and of dendritic spines in particular, is to act as the main contact of the neurotransmitters that arrive from outside. In other words, the dendritic spines act as terminals to which the stimuli arrive from the other neuron that sends neurotransmitters through the synaptic space. Thanks to this, it is possible to establish the transmission of nerve impulses that allows the functioning not only of the brain, but of the entire nervous system, since there are neurons distributed throughout whole body.

On the other hand, the potential of the brain to adapt to circumstances (for example, learning from experience) is also possible thanks to the work of dendrites. It is these that regulate the chances that two nerve cells come into contact with more or less frequency, so they decide the "route" that the nerve impulses take.

Over time, the degree of affinity that the dendrites of one neuron gain with the terminals of another creates a common line of communication, a fact that affects, even minimally, the progress of the mental operations that are being carried out. Of course, this effect multiplied by the number of synapses in the nervous system is not minimal, and not only affects the functioning of the brain and the rest of the system, but is, in itself, the basis of this.

On the surface of dendritic spines are a series of structures called receptors that are responsible for capturing certain types of neurotransmitters and activating a specific mechanism. In this way, a neurotransmitter such as dopamine it will reach a receptor that is compatible with it and will cause it to activate a process in the receiving neuron.

Your role in brain communication

If axons are responsible for making nerve impulses travel through two points in the system nervous, the dendrites are responsible for capturing the chemicals that come out from the tip of the axons and of cause these chemical signals to transform or not into electrical impulses, although this process can also be started in the body of the neuron.

That is it is in the dendrites and in the neuronal body where the electrical signals are born (also called action potentials) that run through neurons and end up at the tips of axons, causing this part of the neuron to release chemicals. When the right amount of neurotransmitters reach the dendrites, depolarization occurs, which is the process that generates nerve impulses.

Dendrites are very sensitive to the slightest variations in the type and amount of neurotransmitters they pick up, and that means that depending on the chemical substances that they detect, they initiate one or another pattern of electrical impulses, or that an electrical signal is not generated directly, if conditions are met.

That means the dendrites don't need to pick up any neurotransmitters so they don't produce an electrical impulse; This can also happen if they capture a certain amount of a certain type of chemical. That is why some psychotropic drugs They act on the dendrites of neurons to prevent them from generating electrical signals as they would if it were not for the effect of this active principle.

In short, the molecular traces that lived experiences leave in the dendrites and in the terminals of the Neurons are the basis for the functioning of the nervous system and its ability to make its activity vary in a way dynamic. At the same time, they are a fundamental part of the memory management process, which are patterns printed in those molecular fingerprints with which the nerve cell works.