Spinal cord, medulla spinalis PDF

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Spinal cord, medulla spinalis...

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Spinal cord, medulla spinalis

Stages of spinal cord embryogenesis. 1) 17-18d. a nerve plaque is formed from the ectoderm. 2) The edges of the nerve plate bend and merge. 3) A neural tube is formed that runs through the entire back of the embryo, from the head to the ulnar end, and ros and brainstem. Stages of brain embryogenesis. 1) 22d. the ventral end of the tube subdivided by blunt ridges into three vesicles: the forebrain, prosencepha lon; middle brain, mesencephalon; rhombic brain, rhombencephalon. 2) The fastest growing anterior vesicle. Of which 1 month two new vesicles are formed - the terminal brain, the telence phalon. The remainder is the medulla, the diencephalon, the forebrain. 3) Rhombic vesicle divides into posterior and anterior vesicles. From posterior to oblong, myelencephalon; anterior - posterior, metencephalon. 4) From the dorsal wall of the posterior cerebellum develops a cerebellum whose hemispheres develop for 3 months. 5) A bridge forms from the lower wall of the posterior cerebellum.

Cylindrical shank, slightly compressed from front to rear. Length 45cm, weight 30g. At the major occipital opening, the foramen magnum passes into the oblong brain and tapers to the cone at the bottom, conus medullaris, at L1-2, the bodies of the L3 vertebrae in children. Downstream of the conus medullaris, the filament terminates. Up to S2 (sacrum), the suture is covered with a soft liner, a subnetwork in the lumbar cistern, and below the S2 it grows with a hard liner and terminates in the coccyx of the Co2 vertebra. The spinal cord is 1cm thick and occupies 1/3 of the total spinal canal. In the neck and lumbar region they are thickened: • Neck thickening, intumescentia cervicalis - at C4-6 • Lumbar sacrum thickening, intumescent lumbosacralis - at Th12. They pass large nerves into the extremities (many nerve cells and fiber clusters). The surface of the brain has longitudinal furrows:

• Anterior medial fissure, fissura mediana anterior - most prominent on anterior surface • Posterior middle fossa, sulcus medianus posterior. The furrows divide the brain into 2 symmetric halves. There are 2 furrows on the sides of each side:  anterior lateral furrow, sulcus lateralis anterior;  posterior lateral furrow, sulcus lateralis posterior. The furrow divides the white matter of the spinal cord into 3 fibers: • Posterior fiber, funiculus posterior - located between posterior middle and lateral posterior furrows; • Lateral fiber, funiculus lateralis - between posterior and anterior lateral furrows. • Anterior fiber, funiculus anterior - between anterior lateral furrow and anterior medial fissure. Anterior / motor caudal, radix anterior / motoria - extends along anterior lateral furrows from each segment. It does so with the nerve fibers of motor neurons in the gray matter's frontal horns. Together with the dorsal fins and branches, they reach the striated muscles (shrink). Posterior / sensory root, radix posterior / sensoria - enters posterior lateral furrows into dorsal segment. They start from the dorsal nodes, ganglia spinalia, which are located in the spinal canal adjacent to the intervertebral openings and are composed of pseudounipolar neurons. The central branches of these neurons go to the spinal cord and form the posterior roots. The peripheral branches, which come out of the spinal node, connect to the anterior root and form the dorsal nerve, the spinal nerve, which exits the spinal canal through the intervertebral openings. Peripheral branches extend into the body and terminate in the organs in the nerve endings, the receptors that accept irritations and transform them into nerve impulses that enter peripheral branches into the bodies of spinal neurons and transmit senses to the spinal cord through central branches forming the posterior roots. Therefore the posterior roots are palpable. The segment of the spinal cord is the part of the gray matter of the spinal cord that leaves a pair of anterior and a pair of posterior roots forming a dorsal nerve on each side. The number of segments corresponds to the number of intervertebral openings. • 8 neck segments (C1-C8)

• 12 thoracic segments (Th1-Th12) • 5 waist (L1-L5) • 5 crossovers (S1-S5) • 1-2 tailbone (Co1-Co2) The root complex of the lower lumbar, sacral and caudal segments forms the tail of the horse, cauda equina, which extends downwards from the cone of the spinal cord, conus medullaris and has a posterior suture in the lumbar cistern. Each segment at the respective vertebra is present only in the embryo during the first half of pregnancy. At the other end, and partially in infancy, the spine grows much faster in length than the spinal cord, so that the vertebrae gradually move downward from the dorsal segments of the nouns. Along with the vertebrae, they move down the intervertebral apertures, stretching the roots of the cerebral cortex and changing their position - becoming more vertical. Structure of the spinal cord gray matter, substantia grisea. • The gray matter, substantia grisea - is made up of nerve cell bodies that are concentrated inside the spinal cord. • Consists of 2 columns that extend vertically in each of the symmetrical dorsal planes on the gene side. • Intermediate well, columna intermedia - a layer of gray matter connecting these columns. In the middle of it goes central canal. The central canal, canalis centralis, is the remnant of the embryonic spinal cord, so that it contacts the fourth ventricle at the top, and at the bottom, inside the cerebral cone, ends in a small extension - the terminal ventricle, ventriculus terminalis. This channel may be blocked in some places. • The intermediate well divides the column into: • Anterior well, columna anterior • Posterior well, columna posterior • Central intermediate, substantia intermedia centralis - part of the intermediate well around the central canal. • Lateral intermediate, substantia intermedia lateralis - the lateral and interconnecting part of the intermediate well anterior and posterior wells. C1 to L2-3 form a protrusion. • H-shaped horizontal (bow tie)

• Fore horns, cornua anteriora - Forward and slightly lateral. Their front ends end at a slight margin widening. The size varies with the segment, the largest being in thickening. It is made up of large neurons whose axons form an axial cylinder of myelin fibers passing through the anterior roots, the spinal cord and the peripheral nerves (nerve striated muscles). There are alpha and gamma motoneurons that are focused on the nuclei. Inner nuclei - nerve trunk muscles, lateral - limb muscles.

Lateral horns and central medial compartment - are composed of associative, sensory, and motile neurons. The sensory elements are the dorsal, nucleus dorsalis (the cerebellar wires) and the intermediate, nucleus intermediomedialis nuclei. Movable - intermediate lateral nucleus, nucleus intermediolateralis in lateral horn, corneal lateral (autonomic functions) .This Th1-Th12 and L1-L3 - sympathetic nucleus, S2-S4 - parasympathetic. • Plate - A column of neurons of similar structure and function located along the spinal cord. • Histotopography and function of spinal cord gray matter and plaques (Figure). Structure of spinal cord white matter. • White matter, substantia alba - envelops the gray matter. It consists of nerve fibers that start from the nuclei of the spinal cord and come from the brain. Common start and function fibers are centered around wires and fibers. • Fibers, fasciculus - are made up of associative fibers of common name neurons that connect the dorsal segments. • Wires, tract - connects the spinal cord segments in both directions with the brain stem, cerebellum, midbrain and hindbrain. Depending on the direction of pulse propagation: Ascending wires - sensory, afferent, centrifugal begin from the nuclei of the spinal cord and go to the brain. Lowering wires - movable, .effectual, centrifugal begin in the parts of the brain and end in the gray matter of the spinal cord. • Posterior fiber, funiculus posterior - between posterior middle and lateral posterior furrows. It forms the skeleton of the first sensory neurons in the dorsal nodes. The ascending branches reach the elongated brain. The descending branches descend

through several segments. Closest to the mid furrow are the fibers of the lower cruciate segments (transmits sensations from the feet), the outermost segments, and the outermost segments. • Fibers of the lower 19 segments form a graceful fibula, the fasciculus gracilis, closer to the midline. Fibers of upper thoracic and cervical segments - wedge, fasciculus cuneatus. These are wired structures of the somatosensory system - terminating in the nuclei of the elongated brain. Tactile and deep (joint and proprioceptor) sensations are spread....