Dura mater (brain): anatomy and functions

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

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

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

The dura mater: the outermost of the meninges

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

The outermost of the three and to which this article is dedicated 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 retain 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 most of the nervous system with great precision, reaching from the brain to the sacral vertebrae of the spinal cord.

Both the dura mater and the rest of the meninges contain and are connected by different nerve fibers, possessing multiple pressure and pain receptors. In the dura mater 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 body that are beyond.

Anatomical structure of the dura

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

1. Periosteal layer

The first of the layers of the dura is the so-called periosteal or endosteal layer, this being the part of the meninge that is attached to the skull. It is in this layer that 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, of great strength and with a great content of collagen. It is from this layer where a series of partitions extend, which are what contribute to shaping the brain 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. Brain sickle

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

2.2. Cerebellum tent

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

2.3. Sickle cerebellum

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

2.4. Pituitary tent

It is a septum that surrounds the sella turcica, part of the skull where the hypophysis, which it protects.

Principal 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 previously, are the following.

1. Protects the brain and spinal cord

The main function of the dura 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 harmful external agents, as well as at a physical level, since the presence of the skull, the membrane itself and the cerebrospinal fluid makes it difficult for blows to affect and damage the brain.

2. Helps maintain the shape of the brain

The division into cells of the cranial cavity, which occurs thanks to the septa of the dura mater, allows the structure of different locations and parts of the brain to be maintainedas 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 in the face of mere body movement

4. Irrigate the brain

In the dura a large number of blood vessels are found, especially those in charge of returning to the heart the blood from which the brain has already consumed the nutrients, that is, the veins. Thus, this layer of the meninges plays an important role in making much of the central nervous system work as it should and can evacuate excess blood.

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

5. Perception of pain and brain tension

Both the dura and the rest of the meninges are innervated by different nerves, containing a large number of receptors. These receptors are a mechanism for the physiological detection of problems of a brain nature.. 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 headaches.

This function is especially vital for survival, since the brain itself does not have receptors that can warn of the occurrence of an internal disease. In other words, without the presence of meninges we would not be able to detect Headaches what can we report problems and give us time to react shortly before very delicate areas of the nervous system are damaged.

Bibliographic references:

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