central nervous system
The central nervous system includesspinal cord and brain. The first looks like a slightly flattened back of the stitch. And the brain, located in the cavity of the skull, consists of two hemispheres, a trunk and a cerebellum.
The physiology of the central nervous system governsrelations between the body and the environment, human responses to various stimuli. Also thanks to her coordination of organs and parts of the body. In general, its activity is based on reflexes, because the body reacts to the slightest changes in its environment or in its internal environment.
The central nervous system conducts nervouscommunication with the body as a whole by cranial nerves (12 pairs thereof) and spinal roots (their 31 pairs). From the muscles, skin, partially limbs and internal organs, "information" to the spinal cord is transmitted through the afferent nerves coming from the posterior roots. And the "information" from the skeletal muscles comes to him through the efferent nerves coming from the back roots. The presence or absence of reflexes indicates how the spinal cord works, does it perform a reflex function. Its damage entails a violation of the transmission of all impulses (both afferent and efferent). From the spinal cord to the head and back go the neural pathways that pass necessarily through the entire trunk of the brain, in which they are partially interrupted or terminated. Oculomotor, auditory and optic nerves are laid in the middle brain. Management of metabolism, circulation, nutrition occurs in the diencephalon through the connection of perception (internal and external) with the work of the endocrine and cardiovascular system. The cerebral cortex includes a huge number of neurons. These are cells of different shapes, which are arranged in several layers and are joined together by means of processes. Each section of the cortex is different from other cells, this is due to the function that it performs.
The entire central nervous system, all its departments in theevery act of human behavior work as one whole, thus forming a functional system. From the position of this understanding it is obvious that any reaction, any reflex, is preceded by considerable work. At each point in time, the central nervous system depends on the needs of the body. First of all, they are motivated by an objective premise - a change in the environment within the body. From the point of view of neurophysiology, this mechanism takes place through activation of the cortex of the cerebral hemispheres through the subcortical centers. They send out the impulses that the body most needs at the moment. The central nervous system seeks to satisfy the dominant motivation. To this end, it synthesizes all available information about the state of the external and internal environment of the organism, and then realizes the behavioral act.
The defeat of the central nervous system arisesfor many reasons. These are congenital malformations, and circulatory disorders, the impact of trauma, the effect of tumor or inflammatory processes. The brain and spinal cord develop with defects if the fetus is affected by the following dangerous factors: the mother's transmission during pregnancy of infectious diseases, injury, irradiation with radiation, exposure to toxic substances, alcoholism of both parents or one of them. Not the least role in the occurrence of deviations is played by heredity.
Particularly severe malformations arise whenThe factors listed above affect the fetus in the initial months of pregnancy. Among them, hydrocephalus takes the first place (too much cerebrospinal fluid accumulates in the brain's ventricles) and microcephaly (underdeveloped brain and skull). Affect the defeat of this system and the developmental defects of the spine and bones of the skull.