THE spinal cord,also called the spinal cord, is a portion of the central nervous system which is located inside the spinal canal. The vertebrae, bones that form the spine, provide protection to the spinal cord, which, when injured, can trigger various problems in the individual, such as paralysis. The spinal cord acts on several important processes in our body, ensuring the transport of information to the brain and acting on movements, for example.
Read more: Brain structures - related to activities such as reason and blood pressure control
What is the spinal cord?
The spinal cord is a cord of nervous tissue which is housed inside the spine, without, however, occupying its entire extent. The medulla extends from the foramen magnum (cranial cavity that communicates with the spinal canal) to the region where the junction of the first and second lumbar vertebrae is located.
In the terminal region, there is a thinning of the spinal cord, forming what we call the medullary cone. From the medullary cone follows the
terminal filament, which extends to the coccyx region. The terminal filament is formed by the pia mater, one of the membranes that form the meninges. The meninges are three membranes found surrounding the central nervous system. They are named after dura mater, arachnoid and pia mater.Like the brain, in the spinal cord it is possible to observe a lighter region and a darker one. The lightest region is what we call the white substance, while the darkest is called gray matter. The first is basically made up of myelinated nerve fibers, while the second has dendrites and cell bodies.
White matter is located more outwardly, while gray matter is located more inwardly and is arranged in a way that resembles the letter H. Note that here the arrangement of white and gray matter is different from what we observe in the brain, in which the white matter is more internal.
The spinal cord has a central channel, which is left over from the neural tube cavity. In this channel circulates the cerebrospinal fluid, also called cerebrospinal fluid. This liquid, which circulates slowly, is very important to ensure that nutrients reach the central nervous system and that waste metabolites are removed.
the spinal nerves
You nerves spinal are the nerves that depart from the spinal cord. In total, we have 31 pairs of spinal nerves, which are named according to the region of the spine related to their exit. These 31 pairs of nerves are divided into:
- 8 pairs of cervical spinal nerves
- 12 pairs of thoracic spinal nerves
- 5 pairs of lumbar spinal nerves
- 5 pairs of sacral spinal nerves
- 1 pair of coccygeal spinal nerves
As mentioned, the spinal cord does not extend through the entire spinal column, however, the roots of some nerves extend to the final portion of the spine. These roots of the terminal portion form the so-called equine tail.
Read more: 12 pairs of cranial nerves - connect to the brain and have different functions
Importance of the spinal cord
The spinal cord is an extremely important portion of the central nervous system, being related to the transmission of information from various parts of the body to the brain and from the brain to the body. In addition, the spinal cord is responsible for movement of our body, presenting essential circuits for the movements to happen. Without the spinal cord, even if the brain sends commands, movement is not possible.
The marrow is still responsible for promoting simple responses called reflex acts, which occur independently of the brain. We can observe the occurrence of reflex acts when we place, for example, our hand on a plant with thorns. When touching the thorn, we quickly withdraw our hand, in a response that occurs before we even feel ache.
This removal occurs due to the participation of the spinal cord alone. When we touch the thorns, nerve impulses carry information through the sensory neurons, to the marrow. In this place, motor neurons are responsible for leading the signals to our muscles, so that these contract and the hand is removed from the thorn. Between the sensory and motor neurons, there may still be interneurons or association neurons. This path taken by the nervous impulse is called reflex arc.
Spinal cord injuries
When we better understand the role of the spinal cord, it becomes clear how important this portion of the nervous system is. Spinal cord injuries are related to loss of limb movement, loss of sphincter control, changes in muscle tone, sexual dysfunctions, changes in reflexes, changes in sensitivity, among others problems. All these changes are directly related to the height of the lesion and the size of the damage caused in the structure.
Most spinal cord injuries are related to trauma generated by accidents,such as falls, practices of some sports and traffic accidents. However, we must not forget that some diseases, as well as congenital problems, can affect the spinal cord.
With regard to non-traumatic causes, we can mention: metastases, severe spinal deformities, autoimmune diseases, such as multiple sclerosis,and infectious diseases that can lead to spinal cord involvement. THE transverse myelitis, for example, is an inflammation of the spinal cord that may be related to infections viral or bacterial.
It is noteworthy that all types of spinal cord injuries have a great impact on a person's life. In addition to all the physical problems described, we cannot forget that injuries cause serious impact on the individual's social and psychological aspects. Therefore, care in the treatment of spinal cord injuries should not be restricted to therapies with physiotherapists and physicians, for example. Psychologists play a key role in the recovery of these individuals.
By Vanessa Sardinha dos Santos
Biology teacher
Source: Brazil School - https://brasilescola.uol.com.br/biologia/medula-espinhal.htm
