The white matter of the spinal cord: ascending and descending path

Белое вещество спинного мозга: восходящие и нисходящие путиThe white matter of the spinal cord is the most important element, as it provides signals to different parts of the body. When considering the structure of the spinal cord in the context it is seen that the white substance surrounds the grey.

Despite the fact that the functions of the spinal cord and its organization are studied medical science for a very long time, certain details of the formation and function of white matter is still fraught with many mysteries. Because of the complexity of the organization of the spinal cord, as well as of the processes occurring in the neurons of the area are the reason that not in all cases, when the grasses of this region doctors can completely remove their effects and restore mobility of limbs, or simply the violation of the sensitivity of individual sections of the body.

Why should the white stuff?

Белое вещество спинного мозга: восходящие и нисходящие пути

The structure of white and grey substance in the brain

White and gray matter are closely connected, which is designed to provide the necessary level of transmission of nerve impulses from the Central nervous system to peripheral nerves. The Central nervous system, meaning the brain is in close cooperation with the spinal cord, so most physicians do not share these two main components of the nervous organization in the human body.

So, the main task of the white matter is the transmission of nerve impulses to the Central nervous system and, conversely, the transmission of impulses coming from the brain to the peripheral nerves. Peripheral nerves — a collection of nerve fibres providing the innervation of all the organs and tissues present in the human body. Violation of nerve impulses inevitably leads to loss of sensitivity and control over those or other organs and tissues.

The main task of the white matter is the wiring function which regulates the operation of all parts of the nervous system. Signals, which are received through the white matter of the horns of gray matter extending from the Central nervous system, and in addition, those that are going through the nerve bundles of the white matter from the Central nervous system, is transmitted via the descending pathways of white matter. All signals received from the peripheral nerves, are transmitted to the gray matter and through some bundles of white matter through ascending pathways. White matter consists of myelinated processes.

Белое вещество спинного мозга: восходящие и нисходящие пути

The spinal cord and its pathways

Despite the fact that when cut the white and gray matter of the spinal cord look to be the same and only differ in shade, actually these parts of the spinal cord perform completely different functions and have different structure. How the function columns of the gray matter of the spinal cord, still is largely a mystery, but it is believed that this part is the most ancient, and its main function — converting and information transfer in the CNS.

In the center of the spinal cord is localized to the Central channel which in normal operation is filled with cerebrospinal fluid, are necessary to ensure water-salt balance of the tissues of the spinal cord. The white substance on the one hand in contact with the grey, and the other covered with soft, solid and arachnoid membranes.

Considering that the entire spinal cord is located in spinal canal of the spine, he is divided into 5 segments that are related and have the same names as the spine.

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Anatomical features

Белое вещество спинного мозга: восходящие и нисходящие пути

Brain channel located within the spine

In the context of spinal cord is seen that the gray matter has a much smaller mass than whites. Studies have revealed that the gray matter of the spinal cord has a mass about 12 times less than the mass of white. White matter has a complicated anatomical structure.

The white matter of the spinal cord is formed by several types of nerve cells, which have the different origins. Individual cells are processes of gray. Other cells come from cells sensitive ganglia, which, though not are the structural elements of the spinal cord have a direct relation. The third type of cells is from the ganglion cells of the CNS.

Given the specificity of the nerve cells, it can be concluded that the white matter serves to bind the nerve cells located in different parts of the body. This is very important because during the movement type of muscles are used in different parts of the body, so similar nervous organization allows you to connect the activity of all tissues.

White substance has a pronounced segmentation. So, back, front and side of the furrow delimited, forming the so-called cords:

  • Front cord. Anatomically, the front pillars are located between the front horn of gray matter and the anterior median fissure. This area contains the descending path through which the signal from the cortex, and in addition, from mid-brain to all the organs and tissues of the body.
  • Rear cord. Anatomically, the rear cords are located between the rear and front horns of the gray matter of the spinal cord. Rear cords contain a delicate, wedge-shaped and ascending bundles. These bundles are separated each other, and the separator serve as a rear of an intermediate furrow. A wedge-shaped bundle of nerves contained in the rear region of the cord conducts nerve impulses from the upper extremities to the brain. Gentle beam transmits impulses to the brain from the lower limbs.
  • The lateral cord. Anatomically, it is located between the rear and front horn. In this cord are placed, both the ascending and descending path.
  • The structure of white matter involves a complex system of different length and thickness bezmacernyh and meat nerve fibers in combination with a support fabric, which was assigned glia. Composed of white matter also contains small blood vessels which have almost no connective tissue.

    Anatomically, the white matter of one half associated with white the other half of the junction, and the transverse stretching in front of the Central spinal canal has a white spike. Different fibers are in bundles. It is necessary to consider in more detail the beams, conducting nerve impulses, and their functions.

    The main ascending path

    The ascending paths for the transmission of impulses from peripheral nerves to the brain. Most ascending pathways betrays nerve impulses to the cerebellar and the cortical region of the CNS. Some ascending path of the white matter is so fused with each other that they simply cannot be considered apart. It is possible to allocate 6 independent and soldered together upward beams, lying in the white matter.

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    Белое вещество спинного мозга: восходящие и нисходящие пути

    The communication between the two brain organs

  • A thin beam of Gaulle, and a wedge-shaped beam Burdah. These bundles are formed from special cells of the spinal ganglia. A thin beam 19 is formed from the lower segments. Wedge-shaped beam 12 is formed of top segments. Both of these fiber bundles are integrated into the spinal cord through the posterior roots and pass collaterals special neurons. Axons reach the homonymous nuclei.
  • Ventral and lateral way. Considering what is in every way isolated from sensitive cells of spinal ganglia, which are integrated in the posterior horn. Cells within these bundles, go to gray and relate to the switching of nuclei located in the thalamus.
  • The ventral spinal cerebellar path Gowers. Contains special neurons of the spinal nodes, which pass into the region of the nucleus of Clark. The axons ascend to the upper sections of the trunk Central nervous system, where you start in the ipsilateral half of the cerebellum through its upper legs.
  • The dorsal spinal cerebellar path Flexing. Contains neurons of the spinal nodes at the beginning and then has a switch on the cells of the nuclei in the intermediate zone of the gray matter. Longitudinal axons reach the brain, passing through the lower leg of the cerebellum before moving in the ipsilateral region of the cerebellum.
  • It’s not all ascending paths which lie in the white matter of the spinal cord, but present above the nerve bundles are the most studied.

    The main descending path of the substance of the spinal cord

    Descending pathways are closely associated with a region of gray matter and ganglia. On these beams are transferred to the nervous electrical impulses that emanate from the CNS to the periphery. Downward paths studied at the present time is even smaller than the ascenders. The descending path and the ascending, often intertwined, forming an almost monolithic structure, so some of them should be considered without separation of the individual paths:

  • Ventral and lateral corticospinal path. Originate from pyramidal neurons in the lower layers of the motor area of the cerebral cortex. Then the fibers cross the large cerebral hemispheres, the base of the midbrain, then pass through the ventral divisions of the so-called Varoliev and medulla oblongata, reaching the spinal cord.
  • Tectospinal. Originates from cells in the region of the corpora quadrigemina of the midbrain and ends in a connection region of the anterior horn of mononeuronal.
  • Rubrospinal. Base paths are cells located in the red nuclei of the CNS, are the crossing region of the midbrain, and the end of nerve fibers of this path lies in the region of neurons of the intermediate zone.
  • Vestibulospinal way. It is a collective term that reflects multiple types of bundles, which originate from the vestibular nuclei, located in the region of the medulla oblongata, and ends in the anterior cells of the anterior horns.
  • Oligopoly. Formed nerve cells of the olive, the longitudinal localized in the brain, and ends in mononeuronal.
  • Reticulospinal. Is the connection between the spinal cord and reticular formation.
  • This is the main way that most studied currently. However, it should be noted that there are local bundles, which also perform a conductive function, but connect different segments, at different levels of the spinal cord.

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    What is the danger of damaging the ways

    Despite the fact that the white substance hidden under three membranes covering the spinal cord from damage, and is in the solid skeleton of the spine, there are cases of spinal cord injury at injury. The second cause of the conduction disorders is an infectious lesion, but it occurs not so often. Typically, in spinal trauma, the first thing it suffers from white stuff, as it lies close to the surface of the spinal canal of the spine.

    The degree of dysfunction may depend on characteristics of the injury or damage, so in some cases, the dysfunction is reversible, partly reversible in others, and some may experience irreversible consequences.

    Белое вещество спинного мозга: восходящие и нисходящие путиUsually, irreversible consequences because the spinal cord can be observed with the emergence of a vast divide. In this case, the broken conductor function. In case if there is an injury of the spine in which the spinal nerve compression, there are several options for damage connections between nerve cells in white matter with different consequences.

    In some cases, break certain fibers, but there is the possibility of healing and restoration for the transmission of nerve impulses. The full restoration of the damaged beam can take considerable time, as nerve fibers grow extremely hard, and their integrity depends the possibility of carrying out by them of nerve impulses. In other cases, there may be partial recovery of conduction of electrical impulses through damaged nerve fibers, then the sensitivity in certain parts of the body can be restored, but not fully.

    The degree of trauma is not all that affects the possibility of rehabilitation, since a lot depends on how quickly rendered first aid and how professionally carried out further resuscitation. Nerves began to conduct electrical impulses, need to teach them this. The regeneration process is influenced by other features of the human body, including age, speed of a metabolism, chronic diseases, etc.