The nervous system controles the behaviour of a person or an animal, the function of the body and the detailled external work that an individual does.

However, the nervous system is not responcible for all controle of the bodily functions. The endocrine (hormonal)  system also do some of this controle by means of hormons, signal substances released into the blood and lymph stream and carried to the whole body, or spread throughout local tissues. The nervous system perfoms the controle of most quick responses. The hormonal system contoles slower responses and general tuning of the bodily functions.

The nervous system also has a certain superior controle over the endocrine system. The superior hormonal gland, the pituitary lies just under the brain. The brain sends signals to the pituitary and threreby controls the function of the pituitary. The pituitary sends out hormons that also controle other endocrine (hormonal) glands.

Also signals mediated through the nerves to local body parts, will often make special cells in those parts send out local hormones.

About nerve cells and how they work

The basic constituents of the nerve system and brain are nerve cells. A nerve cell consists of a central part, the soma, of a bundle of short nerve fibres (dendrites) that lead nerve signals towards the soma, and a long nerve fibre (axon) that leads the signals from the soma and a long way out. The axons often have a bundle obf branches at the end that can spread the signal. The axon of one nerve cell and one or more dendrites of another nerve cell are connected by structures called synapses, so that signals can be lead from one cell to another.

Nerve signals carried along nerve fibers are carried by means of a sort of chemo-electric change. Sodium ions go from the outside into the nerve fibre and potassium ions go from the inside to the outside. This ion stream go through channels furnished with gates that can open or close. When this has happened at one place in the nerve fibre, the changed potential will trigger  opening of gates at the next part of the fibre so the same ting happens there, and this way the signal propagates along the nerve fibre.

When signals shall be carried from one nerve cell to another at the synapses, this is done by chemical substances, so called transmittor-substances. Many of these subastances are also used by the hormonal system as hormons.

Some nerve cells are arranged so that they carry signals to the brain from body parts, afferent neurones. Others carry signals from the brain out to the body, efferent neurones.

How the nervous system is organized

The nervous system consists of several parts organized in layers.

The brain is the superior controle module of the whole body. The outer and higher parts of the brain makes plans, and excert the superior controle of the extarnal behaviour.

The inner and lower parts of the brain is a linking instance between the body and the higher brain parts. These parts also controle emotions, motivations or several kinds and general habits.

The spinal cord is a thick cable that transfere nerve impulses between the peripheral nerves and the brain.

The peripheral nervous system consist of two main parts. The autonomic nerve system regulates the internal activities in the body. The voluntary nervous system controles all external, and conscious actions and work.

The autonomic nerve system consist of two parts that have opposite actions upon the internal processes in the body.

The sympatetic nervous system enforces internal actions that support external work and decreases other internal actions, for example will sympatic fibres to the heart increase the heart rate and dilate blood vessels to the muscles in order to facilitate external actions.

The parasympatetic nervous system enforces internal processes like digestion, growth processes, healing processes and decreases thos activities needed to suppoert external work.

The autonomic nerve system controles directly all esternal and voluntary work.

Autonomic and voluntary nerve system are to some extend blended into the same concrete nerves.

How experiences form and develop the nervous system

The nervous system is not formed and developed once for all. It changes and develops all the time throughout the childhood and also in adult life. Functions in the nervous systems that are extensively used will trigger nerve cells important for those functions to develop new connections, so that the tasks can be solved in a stedily more repid and sofisticated way. Existing connections are probably also made more effective this way by producing more resceptors for neurotransmitters.

If a person have many unpleasant and threatening experiences, the functions that support allertness, anxiety and agressiveness will be strongly developed this way. This development is useful, but if they occure without development of structures useful for pleasant tasks and experiences, a person can get an unballanced personality prone towards agressiveness, anxiety, allertness and suspicion.

Principles of drugs to treat mental and neurological problems

Since the propagation of nerve signals is linked by releasing transmitter substances at the synapses, meny drugs modify the handling of transmitter substances.

Some of them mimic these substances and bind to the resceptors, but without triggering a nerve responce. In this way they block the resceptors so that the real transmitor substances manage to make their effects less frequently, and thereby they decrease nerve signals.

Other drugs mimic transmitter substances and give the same effect on the resceptors as the real tramsmitter substances. These drugs will increase the amount of nerve signals.

Other drugs increase the effectiveness of transmitter substance production and thus increase the responsiveness of the nerve system.

Still other drugs increase the speed of reuptake of transmittor substances into the cells and thereby decrease the responsiveness of the nerve paths.

 Both pharmacological drugs and natural remedies work through these principles.

The different drugs work on diffrent types of resceptors. Thereby they affect different parts of the nere system and will give diffrent outer effects.

Some of them decrease or increase specific emotional and cognitive functions. Those decreasing special parts of conscious cognitive functions are used against schizophrenia or mania.

Those decreasing special emotional functions are used against anxiety or other kind of excessive emotions. Those increasing conscious functions are used against depressiuon.

Some decrease or increase general consciousness.  Drugs decreasing general consciousness are used as general anaesthetics. Drugs increasing general consciousness are used as general tonics.

Some drugs decrease or increase special peripherial nerve functions. Those decreaing nerve responsiveness in the perifereal nerve system are used as local anaesthetics.

Natural medicines also often have the aim of making the nerve system more healthier and more effective by furnishing substances that stimulate regeneration and nutrients for the nerve tissues.




The nervous system

These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. This information is nutritional in nature and should not be construed as medical advice. This notice is required by the Federal Food, Drug and Cosmetic Act.