The human brain has been described as the most complex system in the known universe, And not without reason.
It is made up of a network of glial pathways, neurons and nerve pathways and is the most important part of the central nervous system, but its complex structure and function does not mean that we cannot classify the main parts of the brain. .
The main parts of the brain
In humans, the brain or the brain is the part of the central nervous system located at the end of the brain spinal cord, inside the skull. It is, in short, the organ through which we can perform the most complex mental operations and be aware, that is, the sense of self. It is precisely because of this inside the brain that there are a large number of structures working together at high speed, which makes the functioning of the brain, even today, a mystery in many ways. .
To begin to understand what we know about this complex machinery, it is essential to know the parts of the brain, that is, how the structures that make it up can be classified. A good way to categorize the different parts of the brain may be to look at the different formations that form inside the head of a human embryo. This is a total of three structures.
It is the upper part of the spinal cord and throughout the development of the fetus, it will transform into structures responsible for performing the tasks essential to survival, Such as heart rate and respiratory control. It will eventually turn into a cerebellum, trunk bridge, and medulla oblongata, as we will see.
In human embryos, it appears just above the hindbrain, and will be transformed in the medial part of the brain, also responsible for performing many basic survival functions but which also serves as a bridge between the other two structures.
Located at the end of the spinal cord and on the side closest to the face of the embryo, the forebrain is the formation that will be transformed into the parts of the brain that have appeared most recently in our evolutionary line and which by therefore, they have to do with using language, planning and finding creative solutions to new problems. As we will see, the two main structures that give way to the development of the hindbrain are the diencephalon and the telencephalon.
Parts of the adult brain
Going into more detail, we can stop to look at the different components of the brain in fully developed humans. It is in this set of organs that we find all of those parts of the brain that define how our mind works.
Here we will first see the parts of the brain generated from the forebrain, and then we will move to the midbrain and hindbrain area, in that order.
The telencephalon is the part of the brain that is easiest to see with the naked eye, since it occupies most of the brain’s surface. Its components are the cerebral cortex, the basal ganglia and the limbic system.
2.1.1. Cerebral cortex
The cerebral cortex (or cortex) is the part of the brain that is rough and full of folds.. It covers the rest of the brain and is the area in which the information necessary to carry out the most complex mental processes is integrated, because the information that reaches this region has already been partially processed by other brain structures. The cortex is divided into two cerebral hemispheres that are almost symmetrical to the naked eye, although on a microscopic scale they are very different.
Outraged, each hemisphere is made up of several brain lobes, Each of which is more involved in certain mental processes. The brain lobes are:
- You can read more about this in this article on brain lobes.
2.1.2. basal ganglia
The second component of the telencephalon is the whole formed by the central gray nuclei. It is a group of structures located under the cerebral cortex and distributed symmetrically under each of the hemispheres. The basal ganglia are the pale globe, putamen, and caudate nucleus, which are supplemented by a region known as the substantia nigra.
The basal ganglia are the parts of the brain that allow us to perform relatively complex and precise movements easily and almost automatically: write, speak, voluntarily modify our facial expressions, Etc. Therefore, they semi-automatically monitor how we perform chains of movements that we have practiced many times before to master them, and at the same time allow us to learn them well, among other functions.
- To learn more about this set of brain structures, you can consult the article dedicated to the basal ganglia.
2.1.3. Limbic system
The limbic system is a set of brain structures whose boundaries are quite blurred, As it mixes with many different parts of the brain. Their functions are related to the appearance and regulation of emotions and bodily responses beyond the head that accompanies them. This is why it is sometimes considered as the “emotional brain” as opposed to the “rational brain” which would correspond to the areas occupied by the cerebral cortex (and in particular the frontal lobe).
However, neither the limbic system nor the cortex can function well independentlyAnd so this distinction between rational and emotional areas is very artificial, especially since we are not as rational as it might seem.
If you want to know more about this part of the brain, you can go to this article on the limbic system.
the seahorse it is an elongated structure located inside the temporal lobes, one of the oldest regions of the cerebral cortex, present in the forms of older mammals. Its function is related to the storage and retrieval of memories, to learning and to spatial navigation.
- You can learn more about this part of the brain in this article dedicated to the hippocampus.
the cerebral tonsil is a set of neurons that group together on the inner face of the temporal lobe of each of the hemispheres. In other words, like the hippocampus, it is one of those parts of the brain that is duplicated in every human brain, with one in each half (left and right) of the brain.
The cerebral amygdala is part of the limbic system, And is one of the most important brain structures when it comes to connecting emotional states to the situations we live in; this is why it plays a key role in the mental processes linked to emotional memory and to the learning associated with it, which are very important. After all, knowing which emotions each type of stimulus or experience is associated with makes us adopt an attitude towards them and opt for some possible reactions and not others.
- You can read more about the amygdala in this article.
The diencephalon is the second large structure that forms the forebrain and is located just below the telencephalon., Deep in the central nervous system. The parts of the brain that make up the diencephalon are basically the thalamus and the hypothalamus.
It is the largest part of the brain, and it is the nucleus into which all information that comes to us through the senses is first integrated. (Except for the smell, which reaches the brain directly through the olfactory bulb of each hemisphere cerebral). The thalamus sends this information to upper areas of the brain, so that it continues to process the information that has started to be synthesized there, and is also able to allow the autonomic nervous system to respond quickly to stimuli that may signify the presence of ‘a danger.
- To learn more about this part of the brain, you can read this article on the thalamus
The hypothalamus is located just below the thalamus and is primarily responsible for keeping the whole organism permanently in a state of homeostasis.That is to say in balance in all respects: body temperature, blood hormone levels, respiratory rate, etc.
In addition, thanks to its ability to make hormones secreted by different glands of the body, it induces us to more or less high states of stress and to a general activation depending on what is happening in other parts of the brain. It is also the structure responsible for the appearance of the state of thirst and hunger.
- You can read more about the hypothalamus in this article
The brainstem, or brainstem, is the part of the brain that is most directly connected to the spinal cord., And is also responsible for performing basic tasks of maintaining vital functions such as involuntary breathing or heart rate. It is formed by the parts that evolve from the midbrain and the hindbrain. Its parts are as follows.
The midbrain is the part of the brainstem that sits just below the diencephalon. It is responsible for the brainstem’s communication with higher structures and vice versa, and is also involved in maintaining the automatic processes that allow us to survive. It is divided into tectum and tegmentum.
Also this structure is known as the Varolio bridge or the troncoencefálico bridge. It is located just below the midbrain.
2.3.3. medulla oblongata
It is the lower part of the brainstem, And their functions are very similar to those of the other two structures in this part of the brain. In addition, it is the link between the brain and the spinal cord. Within the medulla oblongata is a part known as the decussation of the pyramidsThis is where the bundles of nerve fibers from the two hemicampers (the left and right halves of the human body) intersect to move from side to side; this explains why the right hemisphere is responsible for processing information with the left hand while the left is responsible for the other, for example.
- If you want to know more about the brainstem, you can read this article
Next to the medulla oblongata and the protuberance, the cerebellum is the third major structure that evolves from the hindbrain. In addition, the cerebellum and the protuberance are part of a region called the metencephalon.
The cerebellum is one of the parts of the brain with the highest concentration of neurons and among its many functions, the most studied is the regulation and monitoring of complex movements that require some coordination. It also plays a role in maintaining balance when standing and walking.
- If you want to know more about the cerebellum, you can visit this article
Other related nervous system structures
Different parts of the brain don’t just work in coordination with each otherBut they need the participation of other circuits of the neuroendorin system.
These structures and systems, which do not per se belong to the brain, are the cerebral nerves (or cranial pairs) and the autonomic nervous system (ANS).
Cranial pairs are bundles of axons that emerge from different points in the lower brain and they will end up in other parts of the body without passing through the spinal cord. This is what sets them apart from other nerves, which do not originate from different parts of the brain but from different sections of the spinal cord.
Examples of cranial pairs are the trigeminal nerve, the vagus nerve, or the olfactory nerve; all of them are of great importance, and in the case of trigeminal its dysfunction can lead to a lot of pain.
You can read more about these brain nerves in this article.
Autonomous nervous system
The autonomic nervous system is a network of axons, ganglia, and organs that it is responsible for regulating the functions that keep us alive, Such as digestion, involuntary breathing or heartbeat. Therefore, these functions cannot be controlled voluntarily; they are too large and they are fully automated.
This network of neurons interacts mainly with the lower parts of the brain (those of the brainstem) and is divided into the sympathetic system, the parasympathetic system and the enteric system.
Through these communication channels parts of the body are controlled which, being the basis for the survival of the tissues and cells that make up the body, cannot depend on voluntary decisions or the management of attention., Which means that besides being automated processes, even if a person wishes, they cannot intervene on them or stop them, as this could result in immediate death. You can read more about him in this article.
Other related articles:
Types of neurons: characteristics and functions
What are the axons of neurons?
- Bradford, HF (1988). Fundamentals of Neurochemistry. To work.
- Hammond. (2001). Cellular and molecular neurobiology (with CD-ROM). Academic press.
- Kalat, JW (2004). Biological psychology. Thomsomparaninfo.
- Morgado, I. (coordinator) (2005). Psychobiology: from genes to cognition and behavior. Ariel Neuroscience.
- Zuluaga, JA (2001). Neurodevelopment and stimulation. Madrid: Médica Panamericana.