Piamadre (brain): structure and functions of this layer of the meninges
When we talk about the nervous system of the human being, in which the brain is included, we often forget that this set of anatomical structures could not work well without many other parts of the body associated with it. In particular, 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 organism. But, first of all, we briefly review what the meninges are exactly.
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The meninges: definition
The meninges are a series of tissues that line the central nervous system, offering both protection and support for the circulatory system to get blood to many of the areas occupied by neurons and glial cells.
Also, as we will see, the meninges also they serve to produce cerebrospinal fluid , that 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, leaving a space between the brain and hard parts with which it can collide).
On the other hand, the meninges are not a homogeneous structure, but are divided into several layers, each with its properties and with different consistency. They are formed by three membranes, placed one on top of the other. It is, from top to bottom, the dura mater, the arachnoid and the 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 one that is farthest from the bones of the skull and the scalp.
On the other hand, The pia mater is very thin and has the consistency of a flexible mesh , which makes, for example, that on its surface the furrows and fissures of the cerebral cortex that it covers are insinuated.
This is because it creates a suitable means for the passage of the ducts that will transport blood to the cells of the brain and spinal cord. In addition, being so fine can adhere well to the contour of the brain.
- Maybe you're interested: "Dura mater (brain): anatomy and functions"
Types
It is possible to differentiate between two types of pia mater: cranial and spinal .
Spinal pneumonia
The spinal pia mater is responsible for wrapping the entire spinal cord from top to bottom.
Cranial pharynx
Although its composition is almost identical to the previous one, its functions are better suited to the morphological characteristics of the encephalon.
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 a physical support for the veins, and arteries and capillaries that pass from the external environment to irrigate the tissues of the central nervous system. Thus, their presence neurons and glial cells can survive thanks to the combination of oxygen and nutrients that reaches them through the blood .
2. Generation of cerebrospinal fluid
From the pia mater Choroidal fabrics emerge , which in turn germinate the choroidal plexus, places in which the cerebrospinal fluid is secreted.
- Related article: "Cerebrospinal fluid: composition, functions and disorders"
3. A mold for the spinal cord
The consistency and shape of the spinal cord make this anatomical structure is prone to deform . However, the pia mater helps to prevent this from happening, since it ensures that everything remains in place and, at the same time, its function as a mold also prevents it from lengthening due to its severity.
4. Create a filter
Similar to the blood-brain barrier, the pia mater also serves to prevent certain particles and unwanted substances from coming into contact with the neurons and glial cells of the central nervous system. But this protection is more quantitative than qualitative , because by itself the pia mater does not block in a perfect way the passage of concrete elements, but limits the diffusion of these.
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5. Leave a space 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 causes certain proteins and particles to cross between both media, ascending or descending from or into the subarachnoid space.
6. Sensory function associated with pain
The central nervous system does not have pain sensors (nociceptors), but the pia mater itself is in contact with them. That makes that certain accidents such as herniated discs cause pain , allowing us to know that there is something wrong with our body.
- Maybe you're interested: "Nociceptors (pain receptors): definition and types"
Associated disorders
The main diseases that affect the pia mater are those that end up resulting in inflammation, which in this case It is called meningitis . This health problem associated with the pia mater and the arachnoid 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 and the pia mater and the dura mater may 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"
