To control the work of the whole organism or of each individual organ, motor apparatus, conducting pathways of the spinal cord are required. Their main task is the delivery of impulses sent by the human "computer" to the body, limbs. Any failure in the process of sending or receiving impulses of a reflex or sympathetic nature is fraught with serious pathologies of health and all life.
What are pathways in the spinal cord and brain?
The pathways of the brain and spinal cord act as a complex of neural structures. In the course of their work, the impulse shocks are sent to specific areas of gray matter. In fact, impulses are signals that stimulate the body to act upon the call of the brain. Several groups of nerve fibers, various in accordance with functional features, are the pathways of the spinal cord. These include:
- projection nerve endings;
- associative paths;
- commissural binding roots.
In addition, the performance of the spinal conductors necessitates the allocation of the following classification, according to which they can be:
Sensitive perception and motor activity of a person
Sensory or sensitive pathways of the spinal cord and brain serve as an indispensable element of contact between these two complex systems in the body. They send an impulsive message to each organ, muscle fibers, arms and legs. The instantaneous sending of an impulse signal is a fundamental moment in a person performing coordinated coordinated body movements performed by a person without any conscious effort. The impulses sent by the brain, nerve fibers can recognize through touch, a feeling of pain, body temperature, joint-muscular motor.
The motor pathways of the spinal cord determine the quality of the human reflex reaction. Providing the sending of impulse signals from the head to the reflex ends of the ridge and the muscular apparatus, they give a person the ability to self-control motility - coordination. Also on these pathways lies the responsibility for transmitting stimulating shocks towards the visual and auditory organs.
Where are the paths?
Having familiarized yourself with the anatomical features of the spinal cord, you need to figure out where the very pathways of the spinal cord are located, because under this term a lot of nerve matters and fibers are assumed. They are located in specific vital substances: gray and white. Connecting the spinal horns and the cortex of the left and right hemispheres, the pathways through a neural connection provide contact between these two departments.
The functions of the conductors of the most important human organs are to implement the intended tasks with the help of specific departments. In particular, the pathways of the spinal cord are located within the upper vertebrae and head, and this can be described in more detail in this way:
- Associative connections - a kind of "bridges" that connect the area between the cerebral cortex and the nuclei of the cerebrospinal substance. In their structure, fibers of various sizes are found. Relatively short ones do not extend beyond the hemisphere or its cerebral lobe. Longer neurons transmit impulses passing through a certain distance to the gray matter.
- Commissural pathways are a body with a corpus callosum and performing the task of connecting the newly formed sections in the head and spinal cord. Fibers from the main lobe dissolve radially, they are placed in a white spinal substance.
- Projection nerve fibers are located directly in the spinal cord. Their performance makes it possible for impulses to occur in a short time in the hemispheres and establish communication with internal organs. The division into the ascending and descending pathways of the spinal cord concerns fibers of this type.
Ascending and descending conductor system
The ascending pathways of the spinal cord fill the human need for vision, hearing, motor functions and their contact with important body systems. Receptors of these connections are in the space between the hypothalamus and the first segments of the spinal column. The ascending paths of the spinal cord are able to receive and send further an impulse push coming from the surface of the upper layers of the epidermis and mucous membranes, life support organs.
In turn, the descending pathways of the spinal cord include the following elements in their system:
- Pyramidal neuron (originates in the cerebral cortex, then rushes down, bypassing the brain stem; each bundle is located on the spinal horns).
- Central neuron (it is a motor neuron that connects the front horns and cortex of the hemispheres with reflex roots; along with axons, the peripheral nervous system also enters the chain).
- Spinal-cerebellar fibers (conductors of the lower extremities and column of the spinal cord, including sphenoid and thin ligaments).
It is quite difficult for an ordinary person who does not specialize in neurosurgery to understand the system, which is represented by the complex pathways of the spinal cord. The anatomy of this department is indeed an intricate structure consisting of neural impulse transmissions. But it is thanks to it that the human body exists as a whole. Due to the double direction along which the pathways of the spinal cord act, the instantaneous transmission of impulses that carry information from controlled organs is provided.
Conductors of deep sensorics
The structure of the nerve ligaments, acting in the ascending direction, is multi-component. These pathways of the spinal cord are formed by several elements:
- Bourdach beam and Gaulle beam (represent the paths of deep sensitivity located on the back side of the spinal column);
- spinothalamic bundle (located on the side of the spinal column);
- Govers bundle and Flexig bundle (cerebellar paths located on the sides of the column).
Inside the intervertebral nodes , neuron cells of a deep degree of sensitivity are located. The processes located in the peripheral areas terminate in the most suitable muscle tissues, tendons, bone-cartilage fibers and their receptors.
In turn, the central processes of the cells, located behind, keep the direction to the spinal cord. Conducting deep sensitivity, the posterior nerve roots do not penetrate into the gray matter, forming only the posterior spinal columns.
Where such fibers enter the spinal cord, they are divided into short and long. Further, the pathways of the spinal cord and brain go to the hemispheres, where they undergo a cardinal redistribution. Most of them remain in the zones of the anterior and posterior central gyrus, as well as in the crown of the head.
It follows that these paths conduct sensitivity, due to which a person can feel how his muscular-articular apparatus works, feel any vibrational movement or tactile touch. The Gaulle beam, located directly in the center of the spinal cord, distributes sensitivity from the lower torso. The bundle of Burdakh is located above and serves as a conductor of the sensitivity of the upper limbs and the corresponding section of the trunk.
How to learn about the degree of sensory?
You can determine the degree of deep sensitivity with a few simple tests. To perform them, the patient closes his eyes. Its task is to determine the specific direction in which the doctor or researcher makes passive movements in the joints of the fingers, arms or legs. It is also advisable to describe in detail the body posture or position that his limbs have taken.
Using a tuning fork for the subject of vibration sensitivity, it is possible to examine the pathways of the spinal cord. The functions of this device will help to accurately determine the time during which the patient clearly feels the vibration. To do this, take the device and click on it to make a sound. At this point, it is necessary to expose to any bone protrusion on the body. In the case when such sensitivity falls out earlier than in other cases, it can be assumed that the hind pillars are affected.
The test for a sense of localization implies that the patient, closing his eyes, accurately indicates the place where the researcher touched him a few seconds before. A satisfactory indicator is then considered if the patient makes an error within one centimeter.
Sensory sensitization of the skin
The structure of the conduction paths of the spinal cord allows the peripheral level to determine the degree of skin sensitivity. The fact is that the nerve processes of the protoneuron are involved in skin receptors. The processes located in the center as a part of the posterior processes, rush directly to the spinal cord, as a result of which the Lysauer zone forms.
As well as the pathway of deep sensitivity, the cutaneous one consists of several successively combined nerve cells. Compared with the spinothalamic bundle of nerve fibers, information impulses transmitted from the lower extremities or lower torso are slightly higher and in the middle.
Skin sensitivity varies by criteria based on the nature of the stimulus. It happens:
- temperature;
- thermal;
- pain
- tactile.
In this case, the last type of skin sensitivity, as a rule, is transmitted by conductors of deep sensitivity.
How to learn about the pain threshold and temperature difference?
To determine the level of pain, doctors use the pricking method. In the most unexpected places for the patient, the doctor applies several light injections with a pin. The eyes of the patient should be closed, because to see what is happening, he should not.
The temperature sensitivity threshold is easy to determine. In a normal state, a person experiences various sensations at temperatures, the difference of which was about 1-2 °. To identify a pathological defect in the form of a violation of skin sensitivity, doctors use a special apparatus - a thermoesthesiometer. If it is not, you can conduct a test for warm and hot water.
Pathologies associated with impaired pathways
In an upward direction, the pathways of the spinal cord are formed in a position whereby a person can feel tactile touch. For research, you need to take something soft, gentle and in a rhythmic order to conduct a delicate examination to identify the degree of sensitivity, as well as checking the reaction of hairs, bristles, etc.
Disorders caused by skin sensitivity, today consider these:
- Anesthesia - a complete loss of skin sensitivity on a specific surface area of the body. In violation of pain sensitivity, analgesia occurs, with temperature - thermomanesthesia.
- Hyperesthesia is a reverse anesthesia phenomenon that occurs when the threshold of excitation is lowered, and when it increases, hypalgesia appears.
- Improper perception of irritating factors (for example, the patient confuses cold and warm) is called dysesthesia.
- Paresthesia is a violation, the manifestations of which can be a great many, starting from creeping goosebumps, feelings from electric shock and its passage through the whole body.
- Hyperpathy has the most pronounced severity. She is also characterized by damage to the optic tubercle, an increase in the threshold of excitability, the inability to locally determine the stimulus, severe psychoemotional coloration of everything that happens and too sharp a motor reaction.
Features of the structure of downward conductors
The descending pathways of the brain and spinal cord include several ligaments, including:
- pyramidal;
- rubro-spinal;
- vestibulo-spinal;
- reticulo-spinal;
- back longitudinal.
All of the above elements are the motor pathways of the spinal cord, which are the components of the nerve ligaments in a downward direction.
The so-called pyramidal path begins from the largest cells of the same name located in the upper layer of the cerebral hemisphere, mainly in the zone of the central gyrus. The conduction path of the anterior cord of the spinal cord is located here - this important element of the system is directed downward and passes through several sections of the posterior femoral capsule. At the intersection of the medulla oblongata and the spinal cord, an incomplete intersection can be found forming a direct pyramidal bundle.
In the lining of the midbrain there is a conducting rubro-spinal path. It starts from the red cores. Upon exit, its fibers cross and pass into the spinal cord through the varolia and medulla oblongata. The rubro-spinal path allows impulses from the cerebellum and subcortical nodes.
The pathways of the white matter of the spinal cord begin at the Deiters nucleus. Located in the brain stem, the vestibulo-spinal path continues in the dorsal and ends in its front horns. The passage of pulses from the vestibular apparatus to the motor neuron of the peripheral system depends on this conductor.
In the cells of the reticular formation of the hindbrain, the reticulo-spinal path begins, which in the white matter of the spinal cord is scattered by individual bundles mainly from the side and front. In fact, this is the main connecting element between the reflex brain center and the musculoskeletal system.
The posterior longitudinal ligament is also involved in the connection of motor structures with the brain stem. The operation of the oculomotor nuclei and the vestibular apparatus as a whole depends on it. The posterior longitudinal bundle is located in the cervical spine.
The consequences of spinal cord diseases
Thus, the pathways of the spinal cord are vital connecting elements that provide the person with the possibility of movement and sensitivity. The neurophysiology of these pathways is associated with structural features of the spine. It is known that the structure of the spinal cord surrounded by muscle fibers has a cylindrical shape. Inside the substances of the spinal cord, the associative and motor reflex pathways control the functionality of all body systems.
With the occurrence of spinal cord disease, mechanical damage, or congenital malformations, the conductivity between the two main centers can be significantly reduced. Violations of the pathways threaten a person with a complete cessation of motor activity and loss of sensory perception.
The main reason for the lack of impulse conduction is the death of nerve endings. The most difficult degree of conduction disturbance between the brain and spinal cord is paralysis and lack of sensitivity in the limbs. Then, problems can occur in the functioning of the internal organs associated with the brain by a damaged neural ligament. For example, disturbances in the lower part of the spinal trunk carry human-controlled urination and defecation processes.
Are diseases of the spinal cord and pathways treated?
Only emerging degenerative changes almost instantly affect the conduction activity of the spinal cord. Inhibition of reflexes leads to pronounced pathological changes due to the death of neural fibers. It is impossible to completely restore disturbed conduction sites. The disease occurs rapidly and progresses with lightning speed, so gross conduction disturbances can be avoided only if drug treatment is started in a timely manner. The sooner this is done, the more likely there will be a chance to stop the pathological development.
The non-conductivity of the passing paths of the spinal cord needs treatment, the primary task of which will be to stop the processes of dying of nerve endings. This can be achieved only in the case of suppression of factors that influenced the onset of the disease. Only after this, you can start therapy with the goal of the maximum possible restoration of sensitivity and motor functions.
Drug treatment aims to stop the process of dying of brain cells. Their task is also to restore impaired blood supply to the damaged area of the spinal cord. , . . .
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