Dura mater (brain): anatomy and functions

The outermost meninx whose main function is to protect the brain.

The brain is one of the most fundamental organs for the human being, governing both mental processes and cognitive-emotional capacities as well as the different systems and organs of the body, including the control of vital signs.

It is therefore a fundamental and essential organ for life, being necessary a certain protection against any possible damage that could come from the outside. The skull is an excellent protective barrier, but it is not the only barrier present.

There are a series of membranes called meninges between the skull and the brain, which also serve, among other things, to protect the brain. which also serve, among other things, to protect the brain and the nervous system as a whole. One of them is the dura mater.

The dura mater: the outermost of the meninges.

The meninges are a series of three membranes called dura mater, arachnoid and pia mater that surround and protect the brain. These membranes are located between the skull and the brain, being situated one behind the other and circulating between them different Blood vessels and fluids such as cerebrospinal fluid. Their presence is not only in the brain, which they cover in its entirety, but they are also present in a large part of the spinal cord.

The outermost of the three, and the subject of this article, is the dura mater.. It is the thickest and most resistant meninx, in close contact with the skull. Its rigidity and the different extensions that it has covering the brain make it keep its shape and internal consistency. It also contains a large part of the veins that collect the blood used by the brain and return it to the heart. The dura mater covers with great precision most of the nervous system, reaching from the brain to the sacral vertebrae of the spinal cord.

Both the dura as well as the rest of the meninges contain and are connected by different nerve fibers, possessing multiple pressure and pain receptors. In the dura itself, the presence of the trigeminal and vagus nerves, as well as the first three spinal nerves, stand out. It is, in short, a layer of the meninges that acts as a "bridge" between the central nervous system and the elements of the organism beyond.

Anatomical structure of the dura mater

If we analyze the dura mater and its composition, we can observe how this meninx possesses and is composed mainly of two large layers, namely is mainly composed of two large layers, the periosteal layer and the meningeal layer, starting from the latter four large layers, the periosteal layer and the meningeal layer.The latter has four large partitions that divide the skull cavity into different parts or cells.

1. Periosteal layer

The first layer of the dura mater is called the periosteal or endosteal layer, which is the part of the meninx that is attached to the skull. It is in this layer where most of the blood vessels supplying the brain can be found. It is found only at the cranial level, not being present in the spinal cord.

2. Meningeal layer

Subsequently, the meningeal layer can be found, which is very strong and has a high collagen content. It is from this layer where a series of partitions extend, which contribute to give shape to the brain, maintaining the limits between the different structures. maintaining the boundaries between the different structures.

These partitions of the dura mater, which divide the cranial cavity into different cells, are as follows.

2.1. Sickle of the brain

The name sickle of this septum is due to the fact that it cuts or divides the cerebral fossa into two parts. It is located in the middle part of the skull, vertically.

2.2. Tent of the cerebellum

This dura mater septum separates the occipital lobes and the cerebellum. It protects the midbrain. It also delimits and protects the trigeminal nerve.

2.3. Sickle of the cerebellum

As in the sickle of the cerebrum, this septum keeps one of the structures of the cerebrum divided into two halves.. In this case, this septum keeps the two cerebellar hemispheres separate.

2.4. Tent of the hypophysis

This is a septum that envelops the sella turcica, part of the skull where it is housed.It protects the pituitary gland, the part of the skull where the pituitary gland is housed.

Main functions

The existence of the dura mater is a great advantage for human survival.. The main functions of this membrane, although they have been glimpsed above, are the following.

1. It protects the brain and the spinal cord.

The main function of the dura mater and the other meninges is to protect the nervous system.. This protection occurs both at a biological level, since it acts as a filter that hinders the entry of external harmful agents, and at a physical level, since the presence of the skull, the membrane itself and the cerebrospinal fluid make it difficult for shocks to affect and damage the brain.

2. Contributes to maintaining the shape of the brain

The division of the cranial cavity into cells, which occurs thanks to the partitions of the dura mater, allows the structure of the different locations and parts of the brain to be maintained, as well as its general shape.as well as its general shape.

3. Prevents movement of the brain mass

The presence of the meninges keeps the brain in place, limiting the displacement that could occur.limiting the displacement that could occur with the mere movement of the body.

4. They irrigate the brain

In the dura mater a large number of blood vessels are found in the dura mater.The meninges, especially those responsible for returning to the heart the blood from which the brain has already consumed the nutrients, i.e. the veins. Thus, this layer of the meninges plays an important role in ensuring that a large part of the central nervous system functions as it should and is able to evacuate excess blood.

However, this function of the dura mater also exposes it to risks in the form of pathologies, such as very dangerous aneurysms, meningitis-type infections or ischemia.

5. Perception of pain and cerebral tension

Both the dura mater and the rest of the meninges are innervated by different nerves, containing a large number of receptors. These receptors are a mechanism of physiological detection of brain problems.. For example, they allow us to perceive the pain associated with the pressure of the brain against the skull, and are even the main responsible for our suffering from headaches.

This function is especially vital for survival, since the brain itself has no receptors that can warn of the occurrence of an internal malady. In other words, without the presence of the meninges, we would not be able to detect headaches that could warn us of problems and give us time to react shortly before before very delicate areas of the nervous system are damaged.

Bibliographical references:

• Kandel, E.R.; Schwartz, J.H.; Jessell, T.M. (2001). Principles of Neuroscience. Madrid: McGraw Hill
• Martínez, F.; Mañana, G.; Panuncio, A. and Laza, S. (2008). Anatomo-clinical review of meninges and intracranial spaces with special reference to chronic subdural hematoma. Mexican Journal of Neuroscience: 9 (1): 17-60.