The nervous system of the human being, as a product of its phylogenetic evolution, is a very sophisticated system that has allowed us and allows us to relate to the environment, adapt to it and survive. Functions as important as breathing, physiological activation when danger appears, or cognitive functions (such as attention or memory), among others, depend on it.
The complexity of this system means that it is still largely unknown to science. The nervous system has been the subject of study throughout history and, although many questions remain to be resolved in relation to it, we have certain knowledge about its functioning and structure.
Have you ever wondered what a brain looks like on the inside? If we could see the brain and/or spinal cord inside we would realize that there are parts composed of a white color and others composed of a more grayish color. You know why? Keep reading this Psychology-Online article in which we tell you the difference between gray and white matter of the brain.
nerve cells
In the nervous system we can fundamentally find two types of cells: neuroglia cells and neurons.
1. Neuroglial cells
Neuroglial cells are made up of oligodendrocytes, astrocytes, ependymal cells and microglia in the . These cells do not directly participate in information processing but their function is essential for this to occur, since they perform auxiliary tasks and support the function of neurons.
2. Neurons
The is a nerve cell that represents the basic structural and functional unit of the nervous system and whose function consists of the reception, integration and transmission of information (Crossman, AR and Neary, D., 2007). A neuron is made up of:
- A cell body or somametabolic center of the neuron that contains both the nucleus and the cytoplasm.
- Called extensions axons (through which nerve impulses are transmitted from the soma) and dendrites (through which nerve impulses are transmitted to the soma).
In this article we talk about.
What is gray matter
The gray matter is part of the neuronal tissue in which cell bodies or somata are mostly found. We can observe the gray matter, for example, in the cerebral cortex, the cerebellar cortex and part of the spinal cord.
In the following article, you can see.
What is white matter
White matter, according to the American Psychiatric Association’s psychology dictionary, refers to the part of the nervous system whose nerve fibers are wrapped in myelin sheaths. What is myelin? Myelin is a substance made up of lipids and proteins that surrounds nerve fibers and whose characteristics are the following:
- The myelination process begins in the second part of pregnancy and continues even after birth.
- The myelination process is linked to cognitive development.
- In the same way, the pathological process of demyelination can cause diseases such as multiple sclerosis.
- They are formed through oligodendrocytes in the central nervous system.
- Myelin in peripheral nerves is formed from Schwann cells.
- The coating increases the conduction speed of action potentials, allowing information to be transmitted more quickly.
In them we find three types of myelinated nerve fibers that form the white matter:
- Commissural fibers such as the corpus callosum, which mainly connect both hemispheres.
- Association fibers that generally connect different cortical regions of the same hemisphere.
- Projection fibers that connect the cortex and brain stem.
Four differences between gray and white matter of the brain
At this point you will have already been able to observe some differences between both types of substances. However, below we present four differences that we can find between gray matter and white matter.
1. Composition
The first and perhaps most important difference is found in the composition of both substances.
- On the one hand, the white substance It is mainly made up of nerve extensions (mostly axons) that are protected by a myelin sheath.
- On the other, the gray matter It is fundamentally made up of neuronal bodies or somata.
2. Covering of myelin sheaths
Another of the big differences between the two is that:
- While in the white substance we found a myelin coating on fibers.
- This coating is not found in the gray matter.
This fact causes another of the big differences: its color. The white substance receives its color precisely from the amount of myelin it presents.
3. Distribution in the central nervous system
The cortex is composed of gray matter. Inside, formed by white matter, we also find masses of gray matter that form the intracerebellar nuclei such as the dentate nucleus, which would be the largest.
In the same way, the cerebral cortex It is also made up of gray matter. His inside It is mainly made up of white substancealthough here we also find gray matter nucelli in structures such as the thalamus, the basal nuclei or the striatum, among others.
The spinal cord contains “H”-shaped gray matter surrounded by white matter. Following Snell (2003), at a more practical level we can differentiate that in the spinal cord we find:
- Motor and sensory nerve cells that would make up the gray matter.
- Ascending and descending tracts that would correspond to the white matter.
4. Related functions
In a simplified way, we can relate, mainly:
- To the regions composed of gray matter with the functions of information processing.
- While the connection functions They relate to the parts in which we find the white substance.
This article is merely informative, at Psychology-Online we do not have the power to make a diagnosis or recommend a treatment. We invite you to go to a psychologist to treat your particular case.
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References
- Crossman, A.R., & Neary, D. (2007). Neuroanatomy. Text and atlas in color. Barcelona: Elsevier Masson
Bibliography
- Crossman, A.R., & Neary, D. (2007). Neuroanatomy. Text and atlas in color. Barcelona: Elsevier Masson
- Snell, R. (2003). Clinical neuroanatomy. Madrid: Panamericana Medical Editorial.