Nervous System

The Nervous System is an anatomical system that consists of neurons and nerves that is responsible for visceral regulation, sensory perception, and controlling actions, such as movement.

Location division
Main articles: Central Nervous System, Peripheral Nervous System

The system is divided into two main subsystems, according to their location:


 * Central Nervous System (CNS): includes the brain and spinal chord.
 * Peripheral Nervous System (PNS): the nerves that make the movements and control the internal organs.



Functional division
The nervous system is divided according to its functions in two subsystems:

Somatic Nervous System
The Somatic Nervous System is responsible for coordinating the body's movements, and also for receiving external stimuli. It is the system that regulates activities that are under conscious control. It controls from the esophag to stomach, small intestine and colon.

In turn, these pathways can be divided according to the direction in which they conduct stimuli:

See Neuron


 * Afferent system by sensory neurons, which carry impulses from a receptor to the CNS
 * Efferent system by motor neurons, which carry impulses from the CNS to an effector
 * Relay system by relay neurons (also called interneurons), which transmit impulses between the sensory and motor neurones.

Autonomic Nervous System
The Autonomic Nervous System makes the functions that do not need consciousness like heart beat, some digestion functions like that of the pancreas, the control of adrenaline and noradrenaline, among others. It is divided in two:


 * Sympathetic: it stimulates organs
 * Parasympathetic: it inhibits organs

Each of those two is subdivided in Afferent and Eferent Systems.