Our nervous system is a system as important as it is delicate and complex, and far from what we might think under general ideas, neither the brain nor the spinal cord are in contact with the bones of our structure. Neither with the skull nor with the spine.
The separation or space that is between them and that has the functionality to protect them, are a system of membranous layers that are called meninges.
In the following article we focus on better understanding what the meninges are, their characteristics and main functions in our body. Knowing also the difference between the three layers that structure the whole.
What are the meninges?
The meninges are a set of membranes with connective tissues that are responsible for covering the Central Nervous System (CNS), even though it is already protected by what we know as the brain and spine. They do not allow the system to affect through blows or external chemical agents.
These membranes also prevent contact of the CNS with its neighboring environment and isolate it. There are mainly two large groups and these are classified by their support, the first being hard (dura mater) and soft (arachnoid and pia mater).
Characteristics of the meninges
The meninges have certain characteristics, which define important elements for their correct functionality and for the performance of their structure as protective membranes. These will be mentioned below for the greater understanding of them and their importance in our Central Nervous System.
They are important parts of the nervous system
They are protective membranes of the nervous system, so they constitute a very important structure for it. They are responsible for lining the inside of the bone cavities and the surface of the nervous tissue, without forgetting to make way for the arterial and venous vessels.
They form a protective membrane
The main reason for the existence of the meninges is their protective functionality. They are different layers responsible for preventing a blow from affecting the main structures of the Central Nervous System. They are of different textures and thicknesses, which allow these factors to be advantageously attributed to their objective.
Block the brain from damage and injury
The meninges are a structure designed to provide a cushioning barrier that prevents, prevents or hinders external elements such as blows, trauma or injuries, causing irreparable damage to our system. That is why they involve precisely essential structures for our body.
They hold the cerebrospinal fluid
The cerebrospinal fluid is one that acts as a protective and liquid covering in the brain, protects against pressure changes. It is formed in the ventricles and is obtained from the filtration of plasma.
This liquid is found from 100 to 200 cc on average and is renewed every eight hours. It is white, odorless, and its colorimetric or density changes reflect the possible presence of an infection or inflammation within the Central Nervous System.
They have spaces between each other
The spaces that exist between the meninges are the object of study. In fact, in theMexican Journal of Neuroscience , an article entitled ” Anatomo-clinical review of the meninges and intracranial spaces with special reference to chronic subdural hematoma ” was developed and published.
In this article, they seek to understand the arrangement of the meninges and the content of the spaces between them to obtain knowledge especially in the field of neurosurgery and imaging.
They can be affected by infections and diseases
The meninges are, although protective, quite vulnerable. They can even get infections that block blood vessels and cause strokes, brain damage or injuries and are often the result of meningitis.
Meningitis is an infection that causes inflammation in those tissues that surround the brain and spinal cord. There are some types that are bacterial meningitis and others that are really compromising. In Emilia Bustillo’s Thesis, a rather complex investigation is carried out on the most important classifications ofMeningitis .
Functions of the meninges
These membranes not only have the ability to protect the brain, even if it is their main function. Next, we mention the wide field that covers the anatomy of our body.
Protect the nervous system
They are arranged in layers and act as selective barriers. They prevent chemical attacks by working in filter mode, preventing the entry of certain substances and particles that are harmful to our organisms, which are retained to protect us from infections, in addition to serving as a buffer against certain types of blows.
Maintain intracranial pressure
Intracranial pressure is defined as the average pressure inside the cranial cavity and it is thanks to the cerebrospinal fluid, which allows protection against pressure changes to be obtained.
It is precisely variations and failures in it or in the meninges, which produce modifications and alterations in pressure. The increase in this may be due to an increase in the pressure of the fluid or elevation of the pressure of the brain itself.
remove brain waste
It works as follows: the lymphatic capillaries of the meninges mobilize the cerebrospinal fluid and with it all its components. When they reach the neck area, the lymphatic nodes filter and eliminate unwanted waste or products.
Keeping the brain nourished
The innermost layer of the meninges is the one that allows the mobilization of blood vessels to nourish the brain. They penetrate the interlocking brain matter and provide the nutrients that allow neural mass to develop.
Fix the structures of the nervous system
The meninges are part of the connective tissue, so they help fix the Central Nervous System and with the production of cerebrospinal fluid, they keep the brain suspended which will allow it to preserve its natural shape.
Filter harmful elements from the nervous system
With the same principle that the elimination of cerebral waste occurs, the meninges are responsible for filtering and extracting foreign and unnecessary components in the cerebrospinal fluid, preventing it from continuing to move through the Central Nervous System.
What are the meninges?
The meninges are three membranes of connective tissue, which, being a thin layer, are responsible for protecting the brain and spinal cord. They are organized as a complex structure to attribute to each one its specificity and its individual characteristics.
Therefore, below we will describe each meninge to recognize the differences that exist between them and the very important individual function they fulfill.
dura mater
The dura mater is the outermost layer, and is on the inner side of the skull bones. In thepreviously citedarticle from the Mexican Journal of Neuroscience , they define it as a thick sheet formed by connective tissue and in which an internal and an external face are described.
It has a pearly white color, it is a strong and fibrous structure and Dr. Henriquez, in his article on the Meninges , exposes its functionality and its complex and extensive structure.
Arachnoid
It is located between the dura mater and the pia mater. It is a thin, impermeable membrane that completely covers the spinal cord, constituting a channel through which the cerebrospinal fluid circulates that surrounds the spinal cord in its entirety. Its name is given by Pacchioni in 1792, when he discovered the villi of this membrane.
It has no blood vessels and does not penetrate into the sulci or fissures, except to follow the falx cerebri and tentorium cerebellum. When the cerebrospinal fluid is found in this area, it is the one that is attributed the shock-absorbing function.
Piamother
It is a thin membrane that covers the surface of the brain. It has sawtooth-shaped extensions towards the dura called dentate ligaments and is the closest to the structures they protect, these being the ones that then maintain close contact with the brain and spinal cord.
In the same way, it behaves like a viscoelastic membrane allowing the stretching property of the brain. It is transparent and the blood vessels are located in it.
University Professional in the area of Human Resources, Postgraduate in Occupational Health and Hygiene of the Work Environment, 14 years of experience in the area of health. Interested in topics of Psychology, Occupational Health, and General Medicine.