The nervous system is the center of information processing. A distinction is made between the central nervous system and the peripheral nervous system. What is the role of each system? What are brain diseases? Exams ? Anatomy, diagram of the different organs.
Definition: what is the nervous system?
“The nervous system is a system which controls all the organs of the human body and whose starting point is the brain” defines Pr Yannick Béjot, head of the General, Vascular and Degenerative Neurology Department at the Dijon Bourgogne University Hospital.
What is his role ?
“All the structures of the nervous system allow the commands that will operate the different organs and also receive sensitive and sensory messages from the outside” explains Professor Yannick Béjot. Sensitive (hot, cold, pain, vibration, etc.) and sensory (visual, auditory, taste, etc.) information known as afferent arrives at the central nervous system via peripheral nervous system. The brain then processes this information and can produce a so-called efferent motor response. This answer goes through spinal cord then by peripheral motor nerves. “These nerves come from the marrow and go to the different organs or muscles or bring back the signals from the different sensory receptors” informs the neurologist. The peripheral afferent or sensory nerves bring information to the central nervous system, conversely the peripheral motor or efferent nerves convey the response from the central nervous system to the muscles, allowing the creation of a movement.
Anatomy: what is it made of?
We distinguish the central nervous systemconsisting of thebrain (brain, cerebellum and brainstem) which is the organ for integrating and processing information and spinal cord and the peripheral nervous system made up of nerves and ganglia (spinal or peripheral nerves which arise from the spinal cord and cranial nerves which arise from the nucleus of the brainstem). Moreover, according to its function, we distinguish the somatic nervous system and the vegetative nervous system or autonomic including the sympathetic system and the parasympathetic system.
Diagram of the nervous system
Central nervous system: what is it?
The organs of the central nervous system analyze and interpret sensory information in order to give motor commands.
The central nervous system is the integration and processing center that controls voluntary or involuntary thoughts, emotions and acts. The organs of the central nervous system (brain and spinal cord) analyze and interpret sensory information in order to give motor commands.
Sympathetic nervous system: what is it?
“The sympathetic nervous system is one of the pathways of the autonomic nervous system” says Professor Béjot The autonomic nervous system has two components with opposite activities: the sympathetic system and the parasympathetic system. “They are defined according to the neurotransmitters involved (especially adrenaline and noradrenaline). They ensure balance in our body and allow it to adapt according to our needs” describes the neurologist. The sympathetic system mobilizes energy and the parasympathetic system is the system of the rest. The sympathetic system predominates in situations of physical exertion or nervous tension. The parasympathetic system saves energy and maintains the body’s basic activities. It predominates at rest and during digestion.
Peripheral nervous system: what is it?
The peripheral nervous system allows the central nervous system to communicate with the external world and the internal environment. The nerves that compose it collect sensitive and sensory information in the periphery and convey it to the central nervous system then transmit the orders to the organs.
Autonomic nervous system: what is it?
It ensures the functioning of the deep organs (heart, intestines, stomach, etc.) and controls, for example, cardiac regulation, blood pressure
The autonomic nervous system (also called the involuntary or vegetative nervous system) is the system that monitors the activities of our organization beyond our control. “This system which is neither motor nor sensory also passes through a system with a central control and peripheral nerves. It ensures the functioning of the deep organs (heart, intestines, stomach, etc.) and controls, for example, cardiac regulation and blood pressure. This is why neurological pathologies sometimes give digestive signs, heart rhythm disorders or blood pressure regulation. This system is a little studied system because it is more difficult to access with the complementary examinations available” emphasizes the doctor.
Somatic nervous system: what is it?
The somatic nervous system is part of the peripheral system and is the reverse of the vegetative or autonomic nervous system. “It’s the one who directs voluntary movements : motricity and sensory response“Informs Professor Béjot.
What are the common diseases of the nervous system?
It is at the level of the central nervous system that there can be the most pathologies.
In the acute dysfunctions of the central nervous system are:
- cerebrovascular accidents (stroke),
- the encephalitis (infection of the brain), usually herpes.
Examples of chronic diseases of the central nervous system are:
- the multiple sclerosis,
- neurodegenerative diseases such as Alzheimer’s disease or the Parkinson disease,
- epilepsy,
- brain tumours.
Peripheral system diseases are also common. “Neuropathies are those for which therapeutic resources are more limited” informs the neurologist.
Other pathologies of the peripheral nervous system:
- damage to the peripheral system by compression, such as carpal tunnel compression,
- the Guillain-Barré syndrome,
- myasthenia gravis.
- The Charcot’s diseaseit is an attack of the central nervous system and the peripheral nervous system.
What are nervous system tests?
Central nervous system exams are imaging exams. “It is mainly aboutBrain or spinal cord MRI to see if there are any lesions“explains Professor Béjot. CT scan or MRI can be performed urgently for a stroke. The pet scan, so-called metabolic imaging (compared to MRI and CT which are morphological imaging), which uses markers to qualify cerebral functioning, for example the hypofunction of certain regions of the brain. “are also used electroencephalogram to measure the electrical activity of the brain or the lumbar puncture to look for signs of central nervous system inflammation or infection” indicates the neurologist. The evaluation of the peripheral nervous system is done with an electroneuromyogram or commonly called electromyogramwhich measures electrical signal conduction in nerves.
Who is the doctor specializing in the nervous system?
The doctor specializing in the nervous system (central and peripheral) is the neurologist. Not to be confused with the psychiatrist who treats mood disorders and not nerves. The neurologist is the one who takes care of strokes, multiple sclerosis, Alzheimer’s disease with geriatricians, epilepsy, Parkinson’s disease and related diseases, peripheral pathologies. There are general neurologistss and, in university hospitals, hyper-specialized neurologists who develop expertise in a field.
Thanks to Pr Yannick Béjot, head of the General, Vascular and Degenerative Neurology Department at the Dijon Bourgogne University Hospital