Cerebrospinal fluid: composition, functions and disorders

It is common knowledge that the brain is located inside the skull, protected among other things by it and by different membranes, such as the meninges.

The proper functioning and protection of this organ is essential for survival., It is therefore necessary to nourish and avoid possible damage, such as that caused by blows or intracranial pressure. In addition, if necessary for continuous operation, waste is generated which can be harmful and must therefore be removed from the system.

In all this participates a fluid of great importance that circulates in the nervous system, known as cerebrospinal fluid.

A general idea of ​​cerebrospinal fluid

Cerebrospinal fluid or cerebrospinal fluid is a substance found in the nervous system, both in the brain and in the spinal cord, Which performs various functions such as protection, maintenance of intracranial pressure and the health of the thinking organ.

Its presence in the nervous system occurs mainly in the subarachnoid space (between the arachnoid and the piamater, two of the meninges that protect the brain) and the cerebral ventricles. It is a transparent liquid of fundamental importance for the preservation and good health of the brain, with a composition similar to that of blood plasma, from which it is derived. Although colorless, different deteriorations and infections can give it different shades, its coloring being a sign of the presence of a problem.

Cerebrospinal fluid life cycle

Cerebrospinal fluid is synthesized in the choroid plexuses, small structures present in the lateral ventricles, the main function of these plexuses being the production of this substance. This production occurs continuously, renewed to maintain a constant amount of this substance.

Once emitted, it flows from the lateral ventricles to the third ventricle and then to the fourth through the Silvio aqueduct. From there, it ends up projecting into the subarachnoid space through an orifice known as the Magendie orifice and the Luschka orifices, openings located in the fourth cerebral ventricle that connect the ventricular system and the meningia during the communication with the magna cistern of the subarachnoid space (located between the arachnoid meninges and piamater). From this point, it travels through the meninges throughout the nervous system, performing various functions in the process.

To complete its life cycle, it is eventually reabsorbed through the arachnoid granules, which connect to the veins present in the dura mater, so that the fluid eventually reaches the bloodstream.

The average life cycle of this substance is about three hours, Between its secretion, its circulation, its collection and its renewal.


As I just mentioned, the composition of cerebrospinal fluid is very similar to that of blood plasmaThe main variations are the comparatively much lower presence of protein (it is estimated that in blood plasma the presence of protein is two hundred times higher) and the type of electrolytes that are part of it.

Aqueous solution, cerebrospinal fluid has several components of great importance for the maintenance of the nervous system, such as vitamins (especially group B), electrolytes, leukocytes, amino acids, hill and nucleic acid.

Within this large number of elements, in the cerebrospinal fluid, the presence of albumin as the main protein component stands out, With others such as prealbumin, alpha-2-macroglobulin or transferrin. Apart from these components, the strong presence of glucose stands out, having a presence of about 50 to 80% in this solution so vital for the brain.

main duties

We visualized a perspective of what cerebrospinal fluid is, where it circulates and what it is made of. However you have to wonder why this substance is so important for the proper functioning of the entire nervous system. To answer this question, you need to see what functions it has.

One of the main functions of cerebrospinal fluid is to be the main mechanism of waste disposal produced by the continuous functioning of the nervous system, Waste likely to seriously impair its operation. Thus, the circulation of cerebrospinal fluid carries these substances and metabolites, which will eventually be excreted by the system. If this substance did not exist, the toxins and excess particles would be sedimented in the regions of the nervous system and adjacent areas, so that many problems arose in the state of living cells: they could not be released from these. leftovers, nor do they access parts of them that can be recycled once they’ve gone to the right place.

Another of the most important functions of the cerebrospinal fluid is to keep the brain nourished, as well as to ensure the consistency of the medium between the different brain cells and the spinal cord. It is a kind of chemical “shock absorber” which allows to increase the room for maneuver in the event of certain hormonal imbalances, for example, and when there are homeostasis problems in general.

Cerebrospinal fluid also allows the brain to stay afloat inside the skull, which significantly reduces its weight. This flotation also serves as a cushion against aggressions, shocks and movements by reducing the possibility of impact against the bones of the skull or external elements.

In addition, the cerebrospinal fluid it has a lot to do with maintaining intracranial pressure, Not making it too big or too small, maintaining a constant balance that allows proper operation.

Finally, it also participates in acting as an immune system, protecting the nervous system from harmful agents. It also helps as a means of transporting hormones.

derivative disorders

Thus, the nervous system has in the cerebrospinal fluid an essential tool to function properly.

however, changes in the synthesis, circulation or reabsorption of this substance may occur, Which can cause different problems, two of which are as follows.

1. Hydrocephalus

This concept refers to the presence of excessive cerebrospinal fluidHaving such a buildup that it causes the brain to press against the skull. Some of the things that can cause it are tumors, infections or trauma, but it is also common to find congenital hydrocephalus, that is, present from birth.

It can cause headaches, vomiting, cognitive or coordination problems or double vision, among other symptoms, being in the case of congenital hydrocephalus a cause of severe developmental difficulties and intellectual deficit. This is usually due to obstructions in the circuit, being a common example that the wizard’s hole is blocked. To treat these problems, surgery can be done to allow fluid to escape to other areas, such as the stomach.

2. Intracranial hypertension / hypotension

Too much or too little cerebrospinal fluid can cause too much or too little pressure in the brain inside the skull for it to function properly. While hypotension is believed to be the result of loss or low production of cerebrospinal fluid, hypertension is believed to be caused by too much of it, which can be serious as it puts pressure on areas of the nervous system and prevents them from functioning properly (or even kills). cell tissue).

In all cases, the changes in the cerebrospinal fluid that may appear in these cases they add to the problems of the heart disease from which it originatesSo the danger increases. Both groups of symptoms should be treated to avoid a chain effect resulting from problems with the functioning of the nervous system and the circulatory system.

Bibliographical references:

  • Rodríguez-Segade, S. (2006). Cerebrospinal fluid. Ed Cont Lab Clin .; 9: 49-56.

  • Rosenberg, Georgia (2008). Cerebral edema and cerebrospinal fluid circulation disorders. A: Bradley, WG; Daroff, RB; Fenichel, GM; Jankovic, J. (ed.). Bradley: Neurology in Clinical Practice. 5th ed. Philadelphia, By: Butterworth-Heinemann Elsevier; 63.

  • Zweckberger, K .; Sakowitz, OW; Unterberg, AW et al. (2009). Intracranial pressure-volume relationship. Physiology and pathophysiology Anesthesiologist. 58: 392-7.

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