What Is the Nervous System?

The nervous system (nervous system) is a system that plays a leading role in the regulation of physiological functions in the body. It is mainly composed of neural tissues and is divided into two parts: the central nervous system and the peripheral nervous system. The central nervous system includes the brain and spinal cord, and the peripheral nervous system includes the cerebral and spinal nerves.

The nervous system (nervous system) is a system that plays a leading role in the regulation of physiological functions in the body. It is mainly composed of neural tissues and is divided into two parts: the central nervous system and the peripheral nervous system. The central nervous system includes the brain and spinal cord, and the peripheral nervous system includes the cerebral and spinal nerves.

brain

spinal cord

nerve

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Chinese name

nervous system

Foreign name

Nervous System

Classification

Central and peripheral nervous system

Scope of application

Medical anatomy and physiology

Central nervous system

The central nervous system (centralnervoussystem = CNS) is the main part of the nervous system, including the spinal cord located in the spinal canal and the brain located in the cranial cavity; its location is often on the central axis of the animal body, and is composed of obvious brain ganglia, ganglia, or brain And spinal cord and the components that connect them. A large number of nerve cells gather together in the central nervous system to form a network or circuit organically; its main function is to transmit, store, and process information, generate various psychological activities, and control and control all the behaviors of animals.

Central nervous system development

The development of a single human fertilized egg into an individual is still relatively mysterious. The reason lies in the complexity of the development process: from a single cell, it has developed into millions of cells with special functions to a few of mature individuals. Ten billion cells, and this complex apex is the development of the central nervous system. The central nervous system is formed by the development of the ectoderm of the embryo. At the stage of the neuroblast, the chordal cord runs through the central axis of the early embryo, and induces the undifferentiated ectoderm cells above it to transform into the primordium of the central nervous system. First, the dorsal ectodermal cells above the spinal cord are elongated and thickened to form a neural plate that is wide anteriorly and narrowly; the edge of the neural plate is thickened and pleated to form a neural fold; the central depression of the neural plate forms a neural groove. Then, the nerve fold moves toward the dorsal midline, and finally closes to form a neural tube, which develops into the brain at the front and spinal cord at the back. From this stage on, the general characteristics of the brain are determined by the growth and bending of the front part of the neural tube. With the gradual enlargement of the cerebral cortex and the generation of cortical folds, a mature brain is formed. In the early stages of human embryonic development, human fetuses and mammalian fetuses have striking similarities. This is the general neuroanatomical feature of central nervous system development.

Peripheral nervous system anatomy observation:

As early as 1906, Bardeen observed the properties of nerve bundle fibers on fetal and adult cadaver specimens, and produced cross-sectional views of the femoral, obturator, and sciatic nerves, showing the areas occupied by major motor and sensory fibers. After the 1940s, Sunderland et al. Applied a microanatomical separation method to comprehensively and systematically study the formation and arrangement of nerve bundles in the main neural trunk of the whole body, and summarized a systematic distribution map of nerve bundles in the neural trunk of the extremities. , And a detailed description of the beam shape changes. Probably due to ethnic reasons, domestic scholars' "according to Tusuo's" surgery performed poorly. For this reason, according to the needs of peripheral neuromicrosurgery technology, Zhong Shizhen, etc. in China, combined with the requirements for qualitative and localization of nerve bundles, used acetic acid immersion to perform surgery under a microscope The nerve bundles and bundle groups in the neural stem of adult corpses were separated and tracked. The distribution of the motor bundle and sensory bundles in the neural trunk was described with emphasis and regularity. The functional bundles or bundle groups of the main neural trunk sections of the Chinese limbs were drawn. Local positioning map. Subsequently, Han Zhen et al. Proposed a simple nerve beam localization method based on natural beam splitting. The above research results facilitate clinical application, provide clinicians with an in-depth understanding of the movement and structure of sensory motor beams in the peripheral nerve trunk, and improve the intraoperative nerve pairing. The combined accuracy has played a positive role in improving the curative effect of the operation.

A study by Jabaley et al. In 1988 showed that the arrangement of peripheral nerves in the proximal segment was very complex and repeated, but the distal end could be separated for a longer distance before merging. The significance of the former is to cut a small part of the nerve bundle in the proximal part of the neural trunk. It may not produce or have a small effect on the innervation of the nerve, which provides an anatomical basis for the Oberlin surgery and the extended Oberlin surgery. The significance of the latter lies in the fact that a single nerve bundle branch can be further freed on the neural trunk to facilitate the repair of more important nerve bundle branches. The anterior interosseous nerve branch, the pronator round muscle branch, and the radial wrist flexor branch can be freed from the median nerve trunk in the lower and middle arms for repair and displacement. In 2002, Li Shaoguang et al. Conducted a microanatomical study of the axillary nerve and found that the axillary nerve can be divided into two large bundle groups at the foramen plane of the four sides. The bundle group consisting of the anterior branch of the axillary nerve that dominates the deltoid muscle travels outside the neural trunk.

The characteristic study of the anatomy of different bundle groups and bundle branches on the neural trunk provides an anatomical basis for improving the efficacy of nerve bundle branch displacement in the treatment of brachial plexus nerve injury and the selection of nerve bundle groups.