it is one of the largest and most complex organs in the body ; inside there are in fact numerous structures and billions of nerves that communicate through innumerable connections – the synapses – that allow the passage of the nervous impulse. Its functions are equally numerous and vary starting from the control of breath and other involuntary activities to that of voluntary movements , passing through the generation of emotions and thoughts .
What is the brain?
It is an organ divided into two hemispheres joined by the corpus callosum , which is connected with the spinal cord through the brain stem . Its outer layer is the cortex , while in its central part there are the basal ganglia and at its base, in a posterior position, the cerebellum is located .
Each hemisphere is divided into several lobes : frontal, parietal, occipital and temporal. Two types of cells are sufficient to form all these structures: neurons (responsible for the passage of the nerve impulse) and glia (which performs a supporting and nourishing function and forms the myelin that envelops the extensions of neurons).
It is surrounded by membranes, the meninges (dura mater, arachnoid and pia mater), which form a triple protection layer . Between arachnoid and pious mother is included the subarachnoid space inside which flows the cerebrospinal fluid produced by the chorioid plexus located in the cavities of the brain (the ventricles).
The ventricles are four in total and are connected by a series of openings – the foramina – and tubes . In the cerebral hemispheres there are the first and second lateral ventricles, which communicate with the third ventricle – located in the central part of the brain and delimited by thalamus and hypothalamus – through the foramen of Monro . This third ventricle is connected to the fourth through a long tubular structure, known as the Silvio aqueduct .
What is the brain used for?
Its functions are multiple and different from each other. By integrating the signals that are perceived through the five senses , it associates a meaning with what happens in the surrounding world; but not only. It controls the thoughts, language, memory, movements of the arms and legs and the functioning of all the organs that are present in the body. Finally – by regulating breathing and heart rate – it determines the reactions to stressful events that can occur in daily life.
Specifically: the left hemisphere is responsible for the functions associated with language ; the right one deals with the interpretation of visual information and spatial processing .
The brain stem works instead as a sort of station through which all messages pass to and from the brain and is responsible for controlling basic functions for the body, such as sleep and breathing. More specifically, the part that takes the name of the midbrain is relevant for the movement of the eyes, while the bridge coordinates the movement of the eyes and face and controls the sensations perceived by the face, balance and hearing. The medulla oblongata controls breathing, heart rhythm, blood pressure and swallowing. Finally – together with part of the thalamus– the brain stem controls the level of wakefulness, allows you to pay attention to the surrounding environment and is involved in controlling the rhythm of sleep. 10 of the 12 cranial nerves originate from the brain stem.
The cerebellum is instead the part that is responsible for coordination and balance, while the cortex – also known as “gray matter” – is the area responsible for the birth of voluntary thoughts and movements. The different lobes also correspond to different functions. The fronts are responsible for judgment and solve problems as well as motor functions, while the parietal lobes control the position of the body , the feelings and the ability to write by hand. The temporal lobes involved in memory and hearing , while in the occipital lobe takes shape in the system capable of processing images .
Inside the brain there is also the hypothalamus ; this is a structure that manages information from the autonomic nervous system and helps regulate certain functions (such as rest, nutrition, sexual behavior, body temperature control, hormone production and movement). It is part – together with the amygdala (responsible for aggressive behavior) and the hippocampus (fundamental for acquiring new information) – of the limbic system, which is the one that controls emotions.
Inside there are – finally – the epiphysis and the pituitary . The former performs a function that is not yet fully understood, but would seem to be involved, for example, in sexual maturation . On the other hand, the pituitary function is well known as a regulator of hormone production , through which it controls the growth, development and function of both various organs and glands .