Each organ or system in the body play a role.At the same time they are all interrelated.The value of the nervous system can not be overestimated.It is responsible for the correlation between all the bodies and their systems, and for the functioning of the organism as a whole.The school early start to get acquainted with this multifaceted concept, as the nervous system.Grade 4 - is still small children who can not deeply understand many complex scientific concepts.
structural units
main structural and functional unit of the nervous system (NS) - neurons.They are complex excitable cells secreting processes and perceive the jitters, it is processed and transmitted to other cells.Neurons may also exert on target cells or modulating the braking effect.They are part of the bio- and hemoregulyatsii body.From a functional point of view, neurons are one of the foundations of the organization of the nervous system.They join several other levels (molecular, sub-cellular, synaptic, nadkletochny).
neuron consists of a body (soma), long process (axon) and small branching processes (dendrites).In different parts of the nervous system, they have a different shape and size.In some of them the length of the axon may reach 1.5 m. From one neuron dendrite extends to 1000.According to him the excitement extends from the receptors to the cell body.Pulses are transmitted along the axon effector cells or other neurons.
In science, there is the concept of "synapse".The axons of neurons, coming to other cells begin to branch out and form numerous end to them.These places are called synapses.Axons form them not only on nerve cells.Synapses are on muscle fibers.These organs of the nervous system are present even in the cells of the endocrine glands and blood capillaries.Nerve fibers are coated with shells glial processes neurons.They perform the function of conducting.
nerve endings
This specialized education, located at the tip of processes of nerve fibers.They ensure that the information in the form of a pulse.The nerve endings are involved in shaping and sensing terminal transmitting apparatus different structural organization.By functional purpose release:
• synapses that transmit nerve impulses between nerve cells;
• receptors (afferent endings), guide information from the scene factors internal or external environment;
• effectors transmit impulses from nerve cells to other tissues.
the nervous system
nervous system (NS) - an integrated set of several interconnected structures.It promotes the coordinated regulation of all organs and provides a response to changing conditions.The human nervous system, which is represented by a photo in the article links the motor activity, sensitivity and performance of other regulatory systems (immune, endocrine).Activities of the National Assembly connected with:
• anatomic penetration in all organs and tissues;
• the establishment and optimization of the relationship between the body and the surrounding environment (environmental, social);
• coordinating all the metabolic processes;
• management of organ systems.
structure
anatomy of the nervous system is very complex.It is a lot of structures, different in structure and purpose.The nervous system, a photo which showed that it penetrates into all organs and tissues of the body, plays an important role as a receiver of internal and external stimuli.For this special sensor designed structures that are in the so-called analyzer.They include special neural devices that are able to perceive incoming information.These include the following:
• proprioceptors collecting information relating to the state of the muscles, fascia, joints, bones;
• exteroreceptors, located in the skin, mucous membranes and sensory organs that can perceive received from the external environment irritants;
• interoreceptors located in the internal organs and tissues and responsible for making biochemical changes.
main importance of the nervous system
NA Working closely connected both with the outside world and with the functioning of the organism.With it comes the perception of information and analysis.Thanks to the recognition of stimuli occurs internal organs coming from outside signals.The nervous system is responsible for the body's reaction to the information.It is due to its interaction with humoral mechanisms of regulation provided by the human adaptability to the surrounding world.
value of the nervous system is to ensure the coordination of the individual parts of the body and maintain its homeostasis (equilibrium).Through her work it takes the device to any changes in the body, called adaptive behavior (state).
basic functions of the National Assembly
functions of the nervous system are quite numerous.The main ones include the following:
• regulation of the vital functions of tissues, organs and systems in the normal mode;
• association (integration) of the body;
• preservation of the human relationship with the environment;
• control of the state of individual organs and body as a whole;
• Software activation and maintenance of tone (working condition);
• definition of the activities of people and their mental health is the foundation of social life.
human nervous system, which is represented by a photo above provides such thought processes:
• perception, learning and processing information;
• analysis and synthesis;
• Formation of motivation;
• comparison with relevant experience;
• goal setting and planning;
• corrective actions (bug fixes);
• evaluating performance;
• make judgments, findings and conclusions, the general (abstract) concepts.
nervous system in addition to the signal carries also trophic function.Thanks to her body secreted biologically active substances provide livelihoods innervated organs.The bodies that lack such recharge, eventually atrophy and die.The functions of the nervous system is very important for humans.When modifying an existing environment using them going adaptation of the organism to new circumstances.
processes taking place in the National Assembly
human nervous system, the scheme is quite simple and straightforward, is responsible for the interaction of the organism and the environment.To ensure that it carried out such processes:
• transduction, is the conversion of irritation in nervous excitement;
• transformation which occurs during the conversion of the incoming excitation with some characteristics in the effluent from other properties;
• distribution of excitation in different directions;
• modeling, which is a way of construction of irritation, he replacement of its source;
• modulation changes the nervous system, or its activities.
value of the human nervous system and the body is in the interaction with the environment.Thus there are different responses to all types of stimuli.The main types of modulation:
• excitation (activation), is to enhance the activity of the nervous structures (this condition is dominant);
• inhibition inhibition (inhibition), which consists in reducing the activity of the nervous structures;
• temporary nervous connection, which is creating new ways of excitation transfer;
• restructuring of plastic, which is represented by sensitization (improvement of excitation transfer) and habituation (deterioration of transmission);
• activation of the body, providing a reflex reaction of the human body.
NA
Tasks The main tasks of the nervous system:
• Reception - capture changes in the internal or external environment.It is implemented using sensor systems and receptors is the perception of mechanical, thermal, chemical, electromagnetic and other types of stimuli.
• Transduction - converting (encoding) the incoming signal to nervous excitement, which is a stream of pulses with the characteristics peculiar irritation.
• Implementation of, consisting in the delivery of the excitation of nerve pathways in the necessary parts of the National Assembly and to the effectors (executive bodies).
• Perception - the creation of a model of the nervous irritation (the construction of its sensory image).This process generates a subjective picture of the world.
• Transformation - Transformation of sensory excitation in the effector.Its purpose is to exercise the body's response to the changes of the medium.Thus there is a downward transfer of excitation from the higher parts of the central nervous system to lower-lying or PNS (working organs, tissues).
• evaluating the results of the National Assembly with the help of feedback and afferent (sensory information transmission).
structure NA
human nervous system, the scheme of which is shown above, is divided structurally and functionally.The work of the National Assembly can not be understood fully, without examining the features of its basic types.Only by studying their function, it is possible to understand the complexity of the whole mechanism.The nervous system is divided into:
• the central (CNS), which carries out the reaction at various levels of complexity, called reflexes.It accepts stimuli received from the environment and from bodies.It includes the brain and spinal cord.
• Peripheral (PNS) connecting the central nervous system with organs and limbs.Its neurons are far away from the brain and spinal cord.It is not protected by bones, so prone to mechanical damage.Only thanks to the proper functioning of PNS possible coordination of human movement.This system is responsible for the body's response to stressful situations and danger.Thanks to her, in such situations, the pulse quickens and raises the level of adrenaline.Peripheral nervous system diseases affecting the CNS.
PNS consists of bundles of nerve fibers.They go far beyond the brain and spinal cord and sent to different bodies.They are called nerves.To PNS are ganglia (nodes).They are the accumulation of nerve cells.
diseases of the peripheral nervous system are divided on such principles: Topographical-anatomical, etiological, pathogenesis, Pathomorphology.These include:
• radiculitis;
• plexitis;
• funikulity;
• mono-, poly- and multinevrity.
etiology of diseases, they are divided into infectious (microbial, viral), toxic, allergic, dyscirculatory, dysmetabolic, traumatic, hereditary, idiopathic, kompressiyno-ischemic, vertebral.Diseases of PNS can be primary (leprosy, leptospirosis, syphilis) and secondary (after a childhood infections, mononucleosis, with periarteritis nodosa).By Pathomorphology and they are divided into the pathogenesis of neuropathy (radiculopathy), neuritis (radiculitis), and neuralgia.
properties of the nervous system
reflex activity is largely determined by the properties of the nerve centers, which represent a set of structures of the central nervous system.Their coordinated activity provides regulation of various bodily functions or reflex acts.The nerve centers are a few common characteristics, define the structure and function of synaptic structures (contact between neurons and other tissues):
• The one-sidedness of the excitation process.It is distributed on the reflex arc in one direction.
• irradiation of excitation lies in the fact that the significant increase in the strength of the stimulus is an expansion of the area involved in the process of neurons.
• summation of excitation.This process is facilitated by the myriad of synaptic contacts.
• High fatigue.Prolonged repeated stimulation of the reflex reaction is weakened.
• Synaptic delay.Time reflex reaction is completely dependent on the speed and the time of propagation of excitation across the synapse.In humans, one such delay is about 1 ms.
• Tone, which is the presence of background activity.
• Plasticity, is a feature significantly modify the overall picture of reflex reactions.
• Convergence of nerve signals, determines the physiological mechanism of the path of the afferent information (the constant flow of nerve impulses).
• Integration of cell functions in the nerve centers.
• Property dominant nerve chamber, characterized by irritability, ability to excitation and summation.
• cephalization nervous system, is to move, the body coordinating the activities in major parts of the central nervous system and the concentration of these functions in the regulation.
