The different parts of neurons tell us a lot about how these small cells work. of the brain.
Neural axons, for example, with their elongated, cable-like shape, allow electricity to flow through them, whether or not they are accompanied by myelin sheaths. Dendrites, in turn, perform another function that we will see now.
What are dendrites and what is their function?
Dendrites are among the neurons that they are distributed all over the bodyThat is, both in the brain and spinal cord and in those of the ganglia, internal organs, muscles, etc.
More precisely, the dendrites these are small branches that come out of the cell body (The part of the neuron in which the nucleus of the cell is located). Compared to the axon, dendrites are generally shorter and thinner, so they end up closer to the cell body.
Outraged, through the surface of the dendrites there is yet another kind of prolongation microscopic. These are small formations called dendritic spines, Which are, in turn, the places where the dendrites perform their main function, as we will see.
Spines and dendritic synapses
Since the time of the famous Spanish neurologist Santiago Ramón i Cajal, it has been known that neurons are small, relatively independent bodies, that is, there is a separation between them. The so-called synaptic spaces are part of this space that separates neurons from each other., What are the points through which these nerve cells transmit information through substances called neurotransmitters.
The function of dendrites in general, and dendritic spines in particular, is that of serve as the main point of contact for neurotransmitters from outside. In other words, the dendritic spines act as terminals to which the stimuli of the other neuron reach, which sends neurotransmitters through the synaptic space. Thanks to this, it is possible to establish the transmission of nerve impulses that allows the functioning of not only the brain, but the entire nervous system, since there are neurons distributed throughout the body.
On the other hand, the potential of the brain to adapt to circumstances (for example, to learn from experience) is also possible through the work of dendrites. They are the ones who regulate the chances of two nerve cells coming into contact more or less frequently, so they decide the “path” taken by the nerve impulse.
Over time, the degree of affinity that the dendrites of one neuron gain with the bounds of another it creates a usual communication channel, Which affects, although minimally, the progress of mental operations that are performed. 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 it.
On the surface of dendritic spines there are a number of structures called receptors that they are responsible for capturing certain types of neurotransmitters and activating a specific mechanism. In this way, a neurotransmitter such as dopamine will reach a receptor compatible with it and cause it to activate a process in the receptor neuron.
Its role in brain communication
While axons are responsible for spreading nerve impulses through two points in the nervous system, dendrites are responsible for capturing chemicals from the tips of axons and transform or not these chemical signals into electrical impulsesAlthough this process can also be initiated in the body of the neuron.
Which means electrical signals are born in the dendrites and in the neuronal body (Also called action potentials) that pass through neurons and end up at the ends of axons, causing chemicals to be released from that part of the neuron. When the right amount of neurotransmitters reach the dendrites, depolarization occurs, Which is the process that generates nerve impulses.
dendrites they are very sensitive to the slightest variations in the type and amount of neurotransmitters they collect, And that means that depending on the chemicals they detect, they trigger either pattern of electrical pulses, or an electrical signal is not directly generated, if the conditions are met.
That means dendrites do not need to pick up neurotransmitters in order not to produce an electrical impulse; it can also happen if they capture a certain amount of a particular type of chemical. This is why certain psychotropic drugs act on the dendrites of neurons, to prevent them from generating electrical signals as they would without the effect of this active principle.
In short, the molecular imprints that lived experiences leave on the dendrites and the endings of neurons are the basis of the functioning of the nervous system and its ability to dynamically vary its activity. At the same time, they are a fundamental part of the memory management process, which are patterns imprinted on those molecular fingerprints that the nerve cell works with.