Central Nervous System (CNS): parts, functions and diseases

The Central Nervous System (CNS) is in charge of controlling both voluntary and involuntary acts. This encompasses not only physical expressions, but also acts of thought.

Thanks to this system we are able to respond in different ways to ever-changing stimuli that our organism receives, as well as coordinating the different physiological processes that keep us with lifetime.

In this article we will take care of reviewing what are the parts of the Central Nervous System (CNS)We will also see how they are classified, and the functions they fulfill in the human body, as well as some of the most common pathologies associated with these structures.

• Related article: "Peripheral nervous system (autonomic and somatic): parts and functions"

What are the parts of the Central Nervous System?

The Central Nervous System is made up of two essential structures not only for the proper functioning of the body, but for its life. These structures are the brain (understood as the encephalon, not just the cerebral cortex) and the spinal cord.

. The first structure is inside the skull and includes parts such as the cerebellum, the cerebral cortex, the diencephalon, and other elements essential for our survival. For its part, the spinal cord projects along the vertebral column, and communicates the brain and the nerves of the Peripheral Nervous System, which are not contained in bone pieces and run through the entire Body.

Now let's see what aspects each of these components are in charge of individually, and how in turn they interconnect so that our body reacts to any perceptible stimulus.

Brain

This organ is without a doubt the most complex of the human body in terms of its level of functioning. According to research in the field of neurosciences, the human brain is made up of approximately 100 billion neurons, which interact with each other establishing an immeasurable amount of connections. On the other hand, most of the nerve cells in the brain are not neurons, but glial cells.

It is estimated that the brain consumes approximately 20% of all the oxygen we breathe. Its weight barely represents a minimum 2% relative to the total of an average human being.

Now let's see what are the parts that make up the brain structure of human beings. First we have the so-called brain lobes, which fulfill different functions. These lobes of the brain are located in the cerebral cortex, which is composed mainly of gray matter, that is, areas in which there is a high concentration of neuronal cells.

The cortex is responsible for the more complex and abstract functions, such as imagination and thought, while the more primitive structures located below, such as the limbic system and the brainstemThey take care of the most basic needs of the species; feeding, sexual reproduction, etc.

1. Frontal lobe

It is in charge of the higher functions of human consciousness, making it one of the most important parts of the Central Nervous System. It takes care of the rational part and the voluntary movements of the person. It is located in the area of ​​the forehead.

2. Temporal lobe

Takes care of memory, hearing, and language. It is located behind the part of the ears.

3. Parietal lobe

It has to do with the perception of sensory stimuli from the environment, and also with the balance of the subject. It is located in the upper area of ​​the head.

4. Occipital lobe

This lobe is the person in charge of receiving visual information and interpreting it. It is located at the back of the head, a little above the nape, and is small compared to the rest of the brain lobes.

• You may be interested: "Parts of the human brain (and functions)"

Spinal cord

This other part of the Central Nervous System (CNS) consists of a series of ramifications, which originate from the brainstem and run down the spinal column; These nerve projections are arranged in a relatively rectilinear column (along the spinal column), so that together they form something like a cord.

The medulla has as its main function connect the brain with the Peripheral Nervous System (PNS), both afferent and efferent. This means that the brain can, through the spinal cord, send signals to the muscles located in the spinal cord. periphery s through the nerves, and at the same time external stimuli perceived from the periphery reach the brain.

Apart from these afferent and efferent functions, the spinal cord endows us with the ability to react involuntarily to some stimuli. thanks to reflections. For example, when you accidentally touch something that is too hot, you involuntarily and quickly remove your hand from that object.

In short, this structure takes care of the mobility of all the muscles necessary for us to carry out any activity; the brain only intervenes to start and stop said activity, or when something unforeseen arises in the performance of said activity.

Central Nervous System Diseases

Taking into consideration that it is an extensive system, as could be seen, the pathologies that may present are just as broad. Now we will see some of the most common.

1. Stroke

It is a failure in terms of blood supply to the brain. This is interrupted for some reason, and therefore the neurons begin to die.

2. Trauma

A bad blow to the head area could cause a brain trauma that affects some lobe or other part of the brain and generate multiple complications.

3. Infections

Viruses that have the ability to reach the Central Nervous System (CNS) represent a source of complications for its operation, giving rise to pathologies such as meningitis or encephalitis.

4. Neurodegenerative diseases

Severe pathologies such as Alzheimer's or Parkinson's disease they produce a lot of damage in many parts of the Central Nervous System.

Bibliographic references:

• Campbell, Neil A.; Jane B. Reece; Lisa A. Urry; Michael L. Cain; Steven A. Wasserman; Peter V. Minorsky; Robert B. Jackson (2008). Biology: Eighth Edition. San Francisco, CA, USA: Pearson / Benjamin Cummings.
• Estomih Mtui, M.J.; FitzGerald, T.; Gruener, G. (2012). Clinical neuroanatomy and neuroscience (6th ed.). Edinburgh: Saunders.
• Rakic, P. (2009). Evolution of the neocortex: a perspective from developmental biology. Nature Reviews. Neuroscience. 10 (10): pp. 724 - 735.
• Richard S. Snell (2003). Clinical neuroanatomy. Panamerican Medical.
• Stein PSG (1999). Neurons, Networks, and Motor Behavior. MIT Press. pp. 38 - 44.