Pia mater (brain): structure and functions of this membrane

When we talk about the human nervous system, which includes the brain, we often forget that this set of anatomical structures could not function well without many other parts of the body associated with she. Specifically, both our brain and spinal cord depend on the protection of a series of protective layers known as meninges.

In this article we will see how is one of these layers of the meninges, the so-called pia mater, and what functions it fulfills in our body. But first, let's briefly review what exactly the meninges are.

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The meninges: definition

The meninges are a series of tissues that cover the central nervous system, offering both protection as a support for the circulatory system to deliver blood to many of the areas occupied by neurons and glial cells.

In addition, as we will see, the meninges also used to produce cerebrospinal fluid, which fills several spaces of the central nervous system and also fulfills a function of protection and support to this part of the organism (for example, by leaving a space between the brain and hard parts with which it can crash).

On the other hand, the meninges are not a homogeneous structure, but are divided into several layers, each with its own properties and with a different consistency. They are made up of three membranes, placed one on top of the other. It is, from top to bottom, dura mater, arachnoid mater, and pia mater.

• Related article: "Meninges: anatomy, parts and functions in the brain"

What is the pia mater?

As we have seen, the pia mater is the deepest layer of the meninges, which means that it is the furthest from the bones of the skull and scalp.

On the other hand, the pia mater is very fine and has the consistency of a flexible mesh, which means, for example, that the grooves and fissures of the cerebral cortex that it covers remain insinuated on its surface.

This is so because it creates a suitable environment for the ducts that will carry blood to the cells of the brain and spinal cord to pass through it. In addition, being so thin, it can adhere well to the contour of the brain.

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Guys

It is possible to differentiate between Two types of pia mater: cranial and spinal.

spinal pia mater

The spinal pia mater is responsible for wrapping the entire spinal cord from top to bottom.

cranial pia mater

Although its composition is almost identical to the previous one, its functions are better adapted to the morphological characteristics of the brain.

functions

Among the main functions of the pia mater are the following.

1. Irrigation of the nervous system

The pia mater is responsible for providing physical support for the veins, arteries and capillaries that pass from the external environment to irrigate the tissues of the central nervous system. Thus, its presence neurons and glial cells can survive thanks to the combination of oxygen and nutrients that reaches them through the blood.

2. Cerebrospinal fluid generation

of the pia mater choroidal tissues emerge, which in turn germinate the choroid plexus, places where cerebrospinal fluid is secreted.

• Related article: "Cerebrospinal fluid: composition, functions and disorders"

3. A cast for the spinal cord

The consistency and shape of the spinal cord make it this anatomical structure is prone to deformation. However, the pia mater helps prevent this from happening, as it ensures that everything stays in place. its site and, at the same time, due to its function as a mold, it also prevents it from lengthening due to the gravity.

4. create a filter

In a similar way to the blood brain barrier, the pia mater also serves to try to prevent certain unwanted particles and substances from coming into contact with the neurons and glial cells of the central nervous system. But this protection is more quantitative than qualitative, since by itself the pia mater does not perfectly block the passage of specific elements, but limits their diffusion.

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5. Leaves a gap between the circulatory system and the nervous system

The pia mater is permeable, but at the same time it is dense enough to create a separation between the nervous system and the blood vessels. This means that certain proteins and particles can cross between both media, ascending or descending from or towards the subarachnoid space.

6. Sensory function associated with pain

The central nervous system does not have pain sensors (nociceptors), but the pia mater is in contact with them. that does that certain accidents such as herniated discs cause pain, allowing us to know that there is something in our body that is not working properly.

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Associated disorders

The main diseases that affect the pia mater are those that end up resulting in inflammation, which in this case is called meningitis. This health problem associated with the pia mater and the arachnoid mater can be caused by certain bacteria, viruses and fungi, sometimes after having suffered an injury in the area.

On the other hand, both the arachnoid mater and the pia mater and the dura mater can be the place where a blockage of the blood vessels occurs, causing ischemic accidents and aneurysms of different severity.

• Related article: "Meningitis: causes, symptoms, treatment and prognosis"