The central nervous system (CNS) is responsible for controlling both voluntary and involuntary acts . This includes not only physical expressions, but also acts of thought.

Thanks to this system we are able to respond in different ways to the stimuli our organism receives, regardless of whether they come from outside (our environment) or inside (physiological reactions).

In this article we will review what the parts of the Central Nervous System (CNS) are, we will also see how they are classified, and the functions it performs in the human body, as well as some of its most common pathologies.

Parts of the Central Nervous System

Basically this portion of the Central Nervous System is composed of two structures that are indispensable not only for the correct functioning of the organism, but also for its life. These structures are the brain and the spinal cord .

Now let’s see what each of these components does individually, and how they in turn are interconnected so that our organism reacts to any perceptible stimulus.

The Brain

This organ is without doubt the most complex in the human body in terms of its level of functioning.

According to research in the field of neuroscience, the human brain is composed of approximately 100 billion neurons , which interact with each other to establish an immeasurable number of connections.

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

Now let’s look at the parts that make up the brain structure of human beings. First we have the so-called brain lobes , which fulfill different functions. These brain lobes are located in the cerebral cortex, which is composed of gray substance.

The cortex takes care of the most complex and abstract functions, such as imagination and thought, while the more primitive structures located below, such as the limbic system and the brain stem, take care of the most basic needs of the species; food, sexual reproduction, etc.

1. Frontal lobe

Is the one in charge of the higher functions of human consciousness . It is in charge of the rational part and the voluntary movements of the person. It is located in the forehead area.

2. Temporal lobe

He is in charge 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 subject’s balance. It is located in the upper area of the head.

4. Occipital lobe

This lobe is in charge of receiving the visual information and interpreting it . It is located at the back of the head, a little above the neck.

The spinal cord

This other portion of the Central Nervous System (CNS) consists of a series of branches, which originate in the brain stem and descend along the spine , these nerve roots are dispersed to both sides of the body.

The main function of the medulla is to connect the brain to the Peripheral Nervous System (PNS) , both afferent and efferent. This means that the brain can, via the spinal cord, send signals to the muscles in the periphery via 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 gives us the ability to react involuntarily to certain stimuli thanks to the reflexes . For example, when you inadvertently touch something that is too hot, you quickly and involuntarily remove your hand from that object.

In short, this structure deals with the mobility of all the muscles necessary for us to carry out any activity; the brain intervenes only to start and stop that activity, or when some unforeseen event occurs in the performance of that activity.

Central Nervous System Diseases

Taking into consideration that it is an extensive system, as it could be evidenced, the pathologies that can present are equally wide. Now we will see some of the most common ones.

1. Stroke

This is a failure in the 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 occasionally affects one lobe or another part of the brain and generate multiple complications.

3. Infections

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

Bibliographic references:

  • Richard S. Snell (2003). Clinical neuroanatomy (5 edition). Pan-American Medical.
  • Stein PSG (1999). Neurons, Networks, and Motor Behavior. MIT Press. pp. 38 – 44.