Features of nervous system in children

Karaganda State Medical University

Department of Histology                     

 

 

 

Report

Theme:Features of nervous system in children

 

 

 

 

 

Done by: Otesh Islam 3017-GM

Checked by:Dauletkalieva J.A

 

 

 

 

 

Karaganda 2014

                                      Plan

• Introduction
• Brain
• Spinal cord
• Physiological reflexes
• Sense organs
• Conclusion
• References

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                                        Introduction

The nervous system is improved and more complicated as the child grows. Its most intensive development occurs in infants and neonates.

At the time of birth, the child's nervous system is still immature. However, it is this system provides adapting baby to new living conditions and regulates vital functions of his body. In the process of adaptation is set metabolism, rearranged the work of the circulatory system, respiration, blood, digestion. After giving birth, all these systems are beginning a new function. It is thanks to the nervous system is provided by the coordinated activity of all body systems.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bookmark the nervous system takes place on the 1st week of fetal development. The highest intensity of division of the nerve cells of the brain to the period from 10 to 18 weeks of fetal development that can be considered a critical period for the formation of the central nervous system. If the number of nerve cells in the adult human is taken as 100%, the time of birth is formed only 25% of the cells to 6 months - 66%, and by year - 90-95%.

 

For childbirth brain relatively large body mass and is: newborn - 1 / 8-1 / 9 1 kg body weight, 1 year old child - 1 / 11-1 / 12, the child 5 years - 1 / 13- 1/14, adult - 1/40.

 

The pace of development of the nervous system is faster, smaller child. Especially it vigorously proceeds during the first 3 months of life. Differentiation of nerve cells is achieved by 3 years, and to 8 years in the cerebral cortex in the structure similar to the cerebral cortex of an adult.

 

Blood supply to the brain in children better than adults. This is due to the richness of the capillary network, which continues to develop after birth. Copious blood supply to the brain meets the needs of the fast-growing nerve tissue oxygen. And its oxygen demand of more than 20 times higher than the muscle.

 

Blood flow to the brain in infants differs from that of adults. This creates an environment conducive to greater accumulation of toxic substances and metabolites in various diseases, which explains the more frequent occurrence in infants of toxic forms of infectious diseases.

 

At the same time, the substance of the brain is very sensitive to an increase in intracranial pressure. CSF pressure increase causes a rapid increase of degenerative changes in the nerve cells, and more prolonged existence of hypertension causes their atrophy and death. This is confirmed in children who suffer from hydrocephalus which developed in utero.

 

Dura mater in neonates is relatively thin, adherent to the base of the skull bones of a large area. Venous sinus thin-walled and relatively longer than in adults. Soft and arachnoid brain newborn extremely thin, subdural and subarachnoid space reduced. The tanks are located on the base of the brain, in contrast, are relatively large. Cerebral aqueduct (Sylvia plumbing) wider than that of adults.

Brain

Mass newborn brain is relatively high and the body weight is 1/8, whereas in adults - 1/40. Children gyrus and sulcus are less pronounced than in adults. After birth, gradually changing their size and shape: furrows become deeper, longer and meanders made larger. Also form new small gyrus and sulcus. The most actively committed this process in the first five years of life. This leads to an increase in the surface of the cortex.

Because of the high demand in newborn brain oxygen, it is better blood supply than in adults. However, infants venous outflow from the brain has certain differences, therefore, the conditions for the accumulation of toxic substances. This feature explains the higher incidence of toxic forms of disease in young children.

As mentioned above, at the time of birth of a baby is the most mature of his spinal cord. The brain, as the structure is more complex by the end of the prenatal period still does not complete its development, not only in morphology (formation of the convolutions of the cerebral cortex, changes the ratio of white and gray matter of the brain), but also functional. So, a very important point is that the number of nerve cells in the cerebral cortex of the newborn child and adult alike. But the newborn, these cells still immature in their structure, they have very little shoots connecting cortical cells among themselves, namely the existence of these links causes many of the functions of the higher nervous activity, such as memory, emotions, skills.

 

However, the development of the cerebral cortex is fast enough, and we notice it by the way the baby is changing rapidly. Just born pipsqueak has not yet been able to hold his head and stare, he distinguishes only a bright light and saw her mother's face as a blur, his movements are chaotic and unconscious. But after a month - and the child makes significant progress in its development. First of all, improving all the senses.

Spinal cord

In contrast to the brain, spinal cord, to the birth of more developed. Newborn spinal cord has a relatively greater length than in the adult. Subsequently, the growth of the spinal cord behind the growth of the spine, so that its lower end as it moves upwards. By the age of six, the ratio of the spinal canal and spinal cord becomes the same as in adults. Until about twenty years continued growth of the spinal cord. Compared with the neonatal period increases its mass at approximately eight times.

Also another characteristic feature of the nervous system in children is a lack of myelin coating of nerve fibers. Myelin - a special substance forming the myelin sheath, which provides high-speed transmission of excitation along the nerve fibers. Pulse propagation velocity along the nerve fibers in children becomes the same as in adults, for 5-9 years. This is due to the completion of various myelination of nerve fibers.

Congenital physiological reflexes

The kid at birth has a number of unconditioned reflexes. All these unconditioned reflexes are divided into two groups. The first group includes persistent lifelong reflexes - swallowing, corneal, conjunctival, and other tendon reflexes. These reflexes are present in humans from birth and persist for life. The second group includes transient reflexes that are normally present in the newborn, but eventually disappear. The second group includes the following reflexes: sucking, search, Proboscis, hand-mouth (Babkin), grasping reflex Robinson, Moro reflex, support, automatic gait, crawl (Bauer), Galant, Peres and others. The appearance of such reflexes in adult pathology and is usually a sign of damage to the nervous system.

Sense organs

By the time of the birth of children are functioning all the senses, but still not perfect - this is due to the immaturity of the centers of the cerebral cortex. For example, the physiological characteristics of the body of a newborn are photophobia, which is stored in the first three weeks, nystagmus (involuntary oscillatory motion frequent eye). In addition, the immaturity of the eye muscles causes physiological neonatal period for strabismus. Also, infants respond WinCE, facial expressions on a loud enough sound, there may vary the depth and frequency of breathing. On the pungent smells kids also respond change in respiratory rate. Taste and touch in newborns developed pretty good. In the future, vision, hearing, taste, smell and touch ripen as the child grows.

Thus, by the time the baby is born, his nervous system is largely formed, and its structure is virtually identical to the adult. However, some of its departments until immature. That is why most of the features of the nervous system is present in infants and young children. During the first years of life the child's nervous system undergoes the greatest amount of change, there is intense maturation of all its departments.

 

 

 

                                       Conclusion

Of course, all organs and systems are important and necessary for the functioning of the human body, but the nervous system stands alone among them, we can say on a pedestal. That it makes the person being reasonable and thoughtful. The main importance of the nervous system is to provide the best fit to the effects of the environment and the implementation of its optimal response to this action. That is why during the first year of baby's life his nervous system is undergoing big changes than any other, is literally developing by leaps and bounds.

In the early stages of development in a growing organism nerve centers have a high degree of ability to adapt compensation. If you violate any activity center of its functions are taken over by other departments of the brain or spinal cord. This ability helps to restore some of the functions affected by the unfavorable course of the prenatal period. This is truly a happy brain's ability allows you to use many of its spare capacity to ensure the proper development of the child.

 

Thus, the nervous system of the baby at birth have largely been formed, its structure is practically no different from an adult, but those of its departments which are responsible for the highest and most complex activity is still very immature. Their maturation lasts throughout the first year of life.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                                    References

• Ekaterina Komar Neonatologists, Rostov Institute of Obstetrics and Pediatrics Magazine "9 Months», №03, 2006
• Mazurin AV Vorontsov I. M ... Propedevtika childhood diseases. SPb .: Folio, 2000.
• Histology, embryology, cytology, a textbook for vuzov.- / Afanasiev YI, Yurina NA / M .: GEOTAR Media, 2012g.- 800.
• Histology. Embryology. Cytology: A textbook for students med.VUZov / Danilov, RK - M: Honey. Inf. Agency, 2006. – 456
• Nervous System Integrated Textbook / Ed. RS Dosmagambetova / M .: Litterra, 2014.-264s.