The nervous system is the integration center and data processing. It is the seat of emotions, thought, conscience. But it also has the task of maintenance of homeostasis. It performs three functions: the receipt and transmission of sensory information, but also integration and response to stimuli.
I – Organization of the nervous system:
It is divided into two main parts: The central nervous system (CNS), comprising the brain and spinal cord and peripheral nervous system (PNS), comprising parts nervous outside the CNS.
- The CNS is the central regulator and integrator of sensory information, from which it develops appropriate motor responses.
- The SNP consists mainly of the nerves, whose main function is to enable the transmission of information and the return of the response prepared by the CNS. Functionally, there are two types of channels: the sensory (or afferent), composed of nerve fibers carrying nerve impulses, and motor or efferent pathways, carrying the response of the CNS. The motor pathways are also divided into the somatic nervous system, also called the voluntary nervous system, because it allows the use of skeletal muscles consciously, and autonomic nervous system, which regulates unconscious (hence independent) activity smooth muscle (heart, digestive system ….). This system also faces two subdivisions, the sympathetic nervous system and parasympathetic, each opposing the other.
II – Histology:
The nervous tissue is very rich in cells, and contains little extracellular space. It is composed of two types of cells, neurons and glial cells. (more…)