The cerebral cortex is the seat of the advanced nerve center and the general headquarters responsible for various human activities. The spinal cord is cylindrical in the spinal canal, giving off 3 1 pair of spinal nerves from top to bottom, which are distributed in the body and internal organs and transmit information between them and the brain. Autonomic nerves include sympathetic nerves and parasympathetic nerves, which are distributed in the heart, blood vessels, endocrine glands, internal organs and other organs. Its function is to regulate various physiological activities of the human body under the control of the central nervous system, such as metabolism, respiration, circulation, blood pressure, secretion, excretion and reproduction.
Physiological characteristics of the nervous system From birth to adulthood, the development of the nervous system has gone through a complicated process.
The essence of newborn brain weighs only 350g, accounting for 1/4 of adult brain. 1 year old, the brain weighs about 950 grams, which is 2.5 times that at birth. With the development of brain tissue, the number and length of nerve cells are also increasing, which provides a material basis for children, but the development is not perfect, and the process of excitation and inhibition of nerve cells is easy to spread and generalize, and it is easy to be excited, tired, unfocused and unstable. At the age of 3~6, although the number of brain cells no longer increases, the cells continue to grow and differentiate, and the branches become longer and deeper, which makes the connections between nerve cells more extensive, so children respond quickly, flexibly and accurately to external stimuli. At the age of 5~6, the metabolism of various substances related to learning and memory in the brain is very active, which is an important stage of intellectual progress in one's life and the best period of intellectual development. At the age of 7~8, the brain weight has increased to about 1400g, which is close to that of adults. Children's movements are more coordinated and accurate, and the brain's inhibitory ability is greatly enhanced. At this time, children have been able to exercise self-restraint on their own desires and emotions, their analytical and comprehensive abilities have been further strengthened, and their ability to learn consciously has also been greatly improved. They can express their consciousness not only in words, but also in words. But this ability is not perfect, for example, it is intuitive, vivid and imitative in learning, but it is poor in abstraction, generalization and thinking. Therefore, in teaching, we should try our best to use visual methods to gradually guide children to form rich imagination and develop in the direction of creative thinking. After 9 years old, the weight of children's and teenagers' brains has not changed much, but the internal structure and function of the brain have become more complicated, which has laid a material foundation for children's thinking activities such as reasoning, imagination, synthesis and induction, and also made their attention and memory more conscious.
Health care of the nervous system The brain is the central part of human beings. To know whether the child's nervous system is developing normally, head circumference measurement can be used as an important indicator to judge the child's brain development. The average head circumference of newborns is about 34 cm. The head circumference increases rapidly within 1 year after birth, reaching 44 cm at 6 months after birth, 46 cm at 1 year, 48 cm at 2 years old, 50 cm at 5 years old, and approaching the adult head circumference at1year old, reaching 54-58 cm. If it is greater than or less than two standard deviations of the normal mean, it should be considered that there may be abnormal brain development. Too small head circumference suggests brain hypoplasia, such as cretinism and microcephaly; If the head circumference is too large, hydrocephalus and rickets may occur; Some mentally retarded children have abnormal head circumference.
Rich nutrition is the material guarantee for the development of nerve cells. Pay special attention to the nutrition supply from pregnancy to six months after delivery, because this period is the most vigorous period of brain cell division. If malnutrition in the early stage will greatly reduce the number of brain cells, it will cause mental retardation in children. Even if the nutritional status improves in the future, this mental retardation is irreversible.
Reasonable daily routine and exercise are the factors to promote the healthy development of nervous system. The younger you are, the easier it is for the cerebral cortex to get excited and get tired. It is very important to arrange the pace of life reasonably and ensure rest and sleep. Because the nervous system almost enters a state of inhibition during sleep, nerve cells can fully recover and store energy, and prepare for study and work after waking up. Therefore, children and adolescents should learn to use their brains scientifically, rest and relax, and improve the working efficiency of their brains. Children and adolescents should have 9~ 10 hours of sleep every day to meet the physiological needs of growth and learning. On the other hand, if the study burden is too heavy, the spirit is highly nervous, life is irregular, sleep is often insufficient, and the brain is unscientific. , will cause memory loss, inattention, academic performance decline, and even serious neurasthenia. Regular physical exercise and moderate labor can promote circulatory function and metabolism, increase cerebral blood circulation and improve the flexibility of nerve reflex.
Children and adolescents should always be cheerful, emotionally stable, energetic and live in a pleasant environment, which is very beneficial to the development of brain cells and the improvement of brain work efficiency.