The main pathways of the spinal cord
To control the work of the whole organism or each individual organ, motor apparatus, conductive pathways of the spinal cord are required. Their main task is to deliver the impulses sent by the human "computer" to the body, limbs. Any failure in the process of sending or receiving pulses of a reflex or sympathetic nature is fraught with serious pathologies of health and all vital activity.
What are the pathways in the spinal cord and brain?
Conducting 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 regions of gray matter. In essence, impulses are signals that induce the body to act upon the call of the brain. Several groups of nerve fibers, different in accordance with functional characteristics, are the conductive pathways of the spinal cord. These include:
- projection nerve endings;
- associative paths;
- commissural bonding roots.
In addition, the performance of 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 conduction pathways of the spinal cord and brain serve as an irreplaceable element of contact between these two most complex systems in the body. They send an impulsive message to every organ, muscle fibers, hands and feet. Instantaneous impulse signal sending is a fundamental moment in the person's implementation of coordinated coordinated body movements performed without any conscious effort. Impulses sent by the brain, nerve fibers can recognize through the sense of touch, the feeling of pain, the temperature regime of the body, the joint-muscle motility.
The motor conductive pathways of the spinal cord predetermine the quality of the human reflex response. Providing the sending of impulse signals from the head to the reflex ends of the ridge and the muscular apparatus, they give the person the ability to self-control the motor skills - coordination. Also on these conducting paths lies the responsibility for the transfer of stimulating tremors towards the visual and auditory organs.
Where are the pathways?
Having become acquainted with the anatomical distinctive features of the spinal cord, it is necessary to understand where the most conducting pathways of the spinal cord are located, as many nerve tissues and fibers are assumed under this term. They are placed in specific vital substances: gray and white. By connecting the cerebrospinal horns and the cortex of the left and right hemispheres, the pathways through neural communication provide contact between the two sections.
The functions of the conductors of the main human organs are to implement the assigned tasks with the help of specific departments. In particular, the conduction pathways of the spinal cord are within the upper vertebrae and head, and in more detail this can be described in the following way:
- Associative connections are peculiar "bridges" that connect areas between the cortex and the nuclei of the spinal cord. In their structure there are fibers of various sizes. Relatively short do not go beyond the hemisphere or its cerebral lobe. Longer neurons transmit impulses that travel a certain distance to the gray matter.
- Comissural pathways are a body that has a callous structure and performs the task of combining the newly formed sections in the head and the spinal cord. The fibers from the main lobe dissolve radiantly, they are placed in the white spinal substance.
- Projection nerve fibers are located directly in the spinal cord. Their working capacity makes it possible for impulses to appear in a short time in the hemispheres and to establish communication with internal organs. The division into the ascending and descending conduction paths of the spinal cord concerns precisely the fibers of this type.
System of ascending and descending wires
The ascending conduction pathways of the spinal cord make up for a person's need for vision, hearing, motor functions and their contact with important body systems. Receptors of these bonds are located in the space between the hypothalamus and the first segments of the spinal column. The ascending ways of the spinal cord are able to receive and send further impulse thrust, coming from the surface of the upper layers of the epidermis and mucous membranes, life support systems.
In turn, the descending conduction pathways of the spinal cord include the following elements in their system:
- The neuron is pyramidal( originating in the cerebral cortex, then rushes down, passing the brain stem, each bundle is located on the spinal horns).
- Neuron central( is a motor that connects the anterior horns and the cortex of the hemispheres with reflex roots, together with the axons, the peripheral nervous system elements also enter the chain).
- Spinal cord fibers( conductors of lower limbs and spinal column, including wedge-shaped and thin ligaments).
An ordinary person who does not specialize in neurosurgery is difficult to understand the system, which is represented by complex conductive 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 her that the human body exists as a whole. Due to the double direction through which the conducting paths of the spinal cord act, instantaneous transmission of impulses is provided, which carry information from the organs being controlled.
Conductors of deep sensor
The structure of the nerve ligaments, acting in the ascending direction, is multi-component. These conduction pathways of the spinal cord are formed by several elements:
- Burdaha's bundle and Gaull's bundle( represent the pathways of deep sensitivity located on the back of the spine);
- spinotalamic bundle( located on the side of the spinal column);
- Hover's bundle and Fleksig's bundle( the cerebellar pathways located on the sides of the column).
Inside the intervertebral nodes are cells of neurons of a deep degree of sensitivity. The processes localized in the peripheral areas terminate in the most suitable muscle tissues, tendons, bone-cartilaginous fibers and their receptors. In turn, the center processes of the cells, being located behind, keep the direction to the spinal cord. With 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. Then the conducting paths of the spinal cord and brain are sent to the hemispheres, where their cardinal redistribution occurs. Most of them remain in the zones of the anterior and posterior central gyri, and also in the region of the crown.
It follows that these paths conduct sensitivity, due to which a person can feel how his musculo-articular apparatus works, feel any vibration movement or tactile touch. The Gaull's bundle, located directly in the center of the spinal cord, distributes the sensitivity from the lower part of the trunk. The bunda Burdaha is located higher and serves as a conductor of the sensitivity of the upper limbs and the corresponding trunk region.
How do I know about the degree of sensorics?
To determine the degree of deep sensitivity, you can use several simple tests. To fulfill them, the patient's eyes are closed. Its task is to determine the specific direction in which the doctor or researcher makes passive movements in the joints of the fingers, hands or feet. It is also advisable to describe in detail the posture of the body or the position that his limbs took.
With the help of a tuning fork for vibration sensitivity, it is possible to investigate the conductive pathways of the spinal cord. The functions of this device will help to accurately determine the time during which the patient clearly feels vibrating. To do this, take the device and press it to make a sound. At this point, you need to put on any bony protrusion on the body. In the case when this sensitivity falls earlier than in other cases, it can be assumed that the posterior columns are affected.
The test for a sense of localization implies that the patient, closing his eyes, points exactly to the place in which a researcher touched him a few seconds before. Satisfactory index is considered if the patient has an error within one centimeter.
Sensory susceptibility of skin
The structure of the spinal cord pathways allows the determination of the degree of skin sensitivity at the peripheral level. The fact is that the neural processes of protoneuron are involved in the skin receptors. The processes located centrally in the posterior processes tend straight to the spinal cord, as a result of which the zone of the Lisauer is formed.
As well as the way of deep sensitivity, the skin is composed of several sequentially united nerve cells. In comparison with the spinotalamic bundle of nerve fibers, information pulses transmitted from the lower limbs or lower trunk are slightly higher and in the middle.
Skin sensitivity varies according to the criteria, based on the nature of the stimulus. It happens:
- is painful;
In this case, the last kind of skin sensitivity, as a rule, is transmitted by conductors of deep sensitivity.
How to learn about pain threshold and temperature difference?
To determine the level of pain, doctors use the method of puncturing. In the most unexpected places for the patient, the doctor applies several light jabs with a pin. The eyes of the patient should be closed, tk. To see what is happening, he should not.
The threshold of temperature sensitivity can not be easily determined. Under normal conditions, a person experiences different sensations at temperatures, the difference being about 1-2 °.To detect a pathological defect in the form of a violation of skin sensitivity, doctors use a special device - a thermoesteziometer. If it does not, you can test for warm and hot water.
Pathology associated with disruption of the conductive pathways
In the ascending direction, the conduction pathways of the spinal cord are formed in a position whereby a person can experience tactile touch. For the study, it is necessary to take something soft, gentle and in a rhythmic manner to conduct a subtle examination to reveal the degree of sensitivity, as well as check the reaction of hairs, setae, etc.
Disorders caused by skin sensitivity are currently considered to be:
- Anesthesia is a complete loss of skin sensitivity on a specific surface area of the body. If pain sensitivity is disturbed, analgesia develops, with thermal - thernesthesia.
- Hyperesthesia - the reverse of anesthesia is a phenomenon that occurs when the threshold of excitation is lowered, as it rises, hypalgesia appears.
- Incorrect 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 huge number, ranging from crawling creeps, feelings of electric shock and its passage through the entire body.
- Hyperpathy is the most striking expression. It is also characteristic of the defeat of the visual hillock, an increase in the threshold of excitability, the inability to locate the stimulus locally, the severe psychoemotional coloring of all that is happening and the too abrupt motor reaction.
Structure features of descending conductors
Descending conductive pathways of the brain and spinal cord include several ligaments, among which:
- is vestibulo-spinal;
- rear longitudinal.
All the above elements are motor pathways of the spinal cord, which are the components of the nerve ligaments in the descending direction.
The so-called pyramidal path starts from the largest cells of the same name, located in the upper layer of the cerebral hemisphere, mainly in the central gyrus zone. Here, too, the conducting path of the anterior cord of the spinal cord is located - 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 straight pyramidal beam.
There is a conductive rubro-spinal path in the midbrain. He takes the beginning from the red cores. When it leaves, the fibers cross and pass into the spinal cord through the variolae and the medulla oblongata. The rubro-spinal pathway allows for pulses from the cerebellum and subcortical nodes.
The conductive pathways of the white matter of the spinal cord begin at the core of Deiters. Located in the brainstem, the vestibulo-spinal path continues in the dorsal and terminates in its anterior horns. From this conductor the passage of impulses from the vestibular apparatus to the motor neuron of the peripheral system depends.
In the cells of the reticular formation of the hindbrain, the reticulo-spinal path begins, which in the white substance of the spinal cord is scattered by separate beams, mainly from the side and from the front. In fact, this is the main link between the reflex cerebral center and the musculoskeletal system.
The posterior longitudinal ligament also participates in connecting the motor structures to the brain stem. The work of the oculomotor nuclei and the vestibular apparatus as a whole depends on it. The posterior longitudinal fascicle is located in the cervical spine.
Consequences of spinal cord diseases
Thus, the conduction pathways of the spinal cord are vital connective elements that provide a person with the ability to move and sense. Neurophysiology of these pathways is related to the peculiarities of the structure of the spine. It is known that the structure of the spinal cord surrounded by muscle fibers has a cylindrical shape. Within the substances of the spinal cord trunk, associative and motor reflex pathways control the functionality of all body systems.
In the event of spinal cord disease, mechanical damage or developmental defects, the conductivity between the two main centers can be significantly reduced. Violations of the conductive paths threaten a person with a complete cessation of motor activity and a loss of sensory perception.
The main reason for the absence of impulse conductivity is the death of nerve endings. The most complex degree of conduction disruption between the brain and spinal cord is paralysis and lack of sensitivity in the limbs. Then, there may be problems in the functioning of the internal organs associated with the brain by a damaged neural ligament. For example, disorders in the lower part of the spinal cord are followed by uncontrolled urination and defecation processes.
Do diseases of the spinal cord and the conductive pathways?
Only emerging degenerative changes almost instantly affect the conductor activity of the spinal cord. The inhibition of reflexes leads to pronounced pathological changes, caused by the death of neuronal fibers. Completely restore the disturbed conduction areas is impossible. The disease comes swiftly and progresses at lightning speed, so you can avoid gross conduction disturbances only if you start medication in time. The sooner this is done, the greater the chances of stopping pathological development.
The non-conductivity of the passing spinal cord pathways requires treatment, the primary task of which will be to stop the processes of the death of nerve endings. This can only be achieved if the factors affecting the onset of the disease have been curbed. Only after that it is possible to start therapy with the aim of the maximum possible restoration of sensitivity and motor functions.
Treatment with medicines is aimed at stopping the process of death of brain cells. Their task is also to restore impaired blood supply to the damaged area of the spinal cord. In the course of treatment, doctors take into account the age features, nature and severity of injury and disease progression. In the therapy of pathways, it is important to maintain constant stimulation of nerve fibers with electrical impulses. This will maintain a satisfactory muscle tone.
Surgical intervention is performed to restore the conductivity of the spinal cord, therefore, it is carried out in two directions:
- Suppression of the causes of paralysis of the activity of neural connections.
- Stimulation of the spinal cord for the speedy acquisition of lost functions.
Prior to the operation, a complete medical examination of the whole organism is required. This will allow to determine the localization of the processes of degeneration of nerve fibers. In the case of severe spinal injuries, it is first necessary to eliminate the causes of compression.