The nervous system is the set of organs and structures that allow you to transmit signals between different parts of the body and allows for the coordination of voluntary and involuntary functions, both physical and psychological.
What is the nervous system?
The nervous system consists of the brain, spinal cord, organs of sense, and all the nerves that connect these organs to the rest of the body
It is possible to distinguish the central nervous system and the peripheral nervous system, in turn they are divided into multiple components, each with a specific function.
The central nervous system
The central nervous system consists of the brain and the spinal cord. In an adult the first contains approximately one hundred billion nerve cells (neurons), and even a greater number of cells that perform support functions (known as glia). Localized inside the cranial box, two hemispheres are formed and joined together and are in direct continuity with the spinal cord, which instead is a cylindrical structure that flows within the spinal column. Both are surrounded by a series of protective membranes (meninges). To also protect them, a cerebrospinal fluid is produced by the brain, which runs within the bounded space of the two meninges (the pia mater and arachnoid). Both nerve branches are directed to other parts of the body.
The peripheral nervous system
The peripheral nervous system can be divided into two main parts: the self-nervous system and the somatic nervous system.
The autonomic nervous system is divided in turn into three parts:
The sympathetic nervous system, the parasympathetic nervous system and enteric nervous system. Neurons whose body is localized in the brain or spinal cord, whose extensions are directed to structures, called ganglia, come into contact with the body of other neurons. The extensions of the latter are directed towards the organ which must be connected to the central nervous system. This particular organization can distinguish preganglionic nerve fibers, formed by the extensions of neurons whose body is localized in the central nervous system, and postganglionic nerve fibers whose cell bodies are located in the ganglia. In the case of the somatic nervous system, they are individual neurons which stand between the central nervous system and the body which must be connected. The cell bodies of these neurons can be found in the brain or spinal cord, we can distinguish the two types: sensory neurons, whose extensions form the nerve fibers that send information from the skin and from the sense organs to the central nervous system, and motor neurons from which the nerve fibers direct information to the skeletal muscles, when those muscles are moved voluntarily.
What function does the nervous system serve?
The nervous system puts in communication the different parts of the body and coordinates their voluntary and involuntary functions. In particular the brain and spinal cord integrate information from other organs and from the external environment and plan the appropriate responses. The different structures in the brain involved in specific functions are responsible for thought, memory, reasoning, understanding, language, involuntary and voluntary movements, balance, posture, breathing, heartbeat, blood pressure, temperature control, emotion, hunger, thirst, the body’s internal biological clock and the reworking of the information received through the five senses, such as sight and hearing.
The spinal cord is responsible for the collection of information directly from the brain, and to organize to which part of the body the signals or information must be sent. It also tests the simple reflexes of the musculoskeletal system.
From the functional point of view the peripheral nervous system can instead be divided into more than one route, which is responsible for transmitting the information from the skin, muscles or from other sense organs to the central nervous system, to control the muscles by sending them the information from the central nervous system, and thus interconnect the brain and spinal cord to the periphery of the body or to connect the internal organs to the central nervous system. In this way the autonomic nervous system controls the glans, internal organs (gastrointestinal tract, pancreas and gallbladder) and their muscles. In particular, the enteric nervous system is responsible for the innervation of the viscera. The somatic nervous system, however allows the central nervous system to perceive sensory information and controls the voluntary muscles.
