The central nervous system is one of the important components of the nervous system, and together with the peripheral nervous system, the nervous system can play a leading role in regulating physiological functions in the body, including the brain and spinal cord, as follows: 1. Brain: The brain is the main component of the central nervous system, which is structurally divided into four parts: telencephalon, mesencephalon, brainstem and cerebellum. The telencephalon is the most complex part of the brain and the most important component, consisting of the frontal lobe, parietal lobe, occipital lobe, temporal lobe, insula and limbic lobe, and the mesencephalon consists of the thalamus, hypothalamus, superior thalamus and basal thalamus. The brainstem includes the midbrain, pontine brain and medulla oblongata. The midbrain is located above the cerebral bridge, and the cerebral peduncle is distributed with motor fiber walks and motor-ocular nuclei, and is the reflex center of vision and hearing, with a reticular nerve tissue in the center, known as the reticular formation, which can control sleep, wakefulness, attention and other states of consciousness; 2. Spinal cord: located within the vertebral canal, it is a slightly flattened cylindrical shape in appearance, and is the central nervous system The anterior horn cells of the spinal cord are motor neurons that send out motor nerves to innervate muscles, which can cause paralysis after injury. The spinal cord mainly performs conduction and reflex functions. In addition to the head, the sensations of the deep and superficial parts of the body as well as the sensations of the internal organs have to be transmitted to the brain through the white matter of the spinal cord. If the spinal cord is damaged, the normal communication of functions will be affected, causing consequences such as sensory impairment and ataxia. There are many low-level reflex centers in the spinal cord that can perform basic reflexes, such as the low-level reflex center for sexual activity, the muscle pull reflex center, the urinary and defecation center, the plantar reflex, the knee-jerk reflex, the visceral reflex, and other somatic reflexes.