1.central nervous system CNS that is protected by bones skull and the spine, and moreover by three membranes called meninges.

2.Peripheral nervous system: that is made of nerves and connects Receptors and effectors to central nervous system.

Central nervous system CNS

It is formed by brain (inside Skull) and spinal cord (inside spine)

Brain has 4 different organs:Cerebrum: Is the only one conscious, it functions are: Receiving and processing stimuli from sensory organs, producing responses to Them, and superior functions such as: memory, reasoning, intelligence and will.It Structure is divided in two hemispheres each one is folded in ridges (circumvoluciones) that carry out specific function. Cutting it we can see grey Matter (formed by neurons cell body) outside (cerebral cortex), and white Matter (formed by axon) inside.Neuronal Plasticity make changes constantly and new learning and memories can be stored.Cerebellum: has the same structure that cerebrum. It is in charge of maintaining equilibrium and executing learnt Movements. It Is unconscious.Brain system: Thalamus (unconscious) associate An emotion to each stimuli, controls our necessities and desires, sleep , Visual auditory reflexes, moreover connects with endocrine system by Hypothalamus.Spinal bulb: Unconscious, regulate body organ Functions such as breathing, heartbeat, digestion…Spinal cord: Is in charge of producing body Reflexes, and carrying information between brain and the rest of the body.  Cutting it we can see grey matter (formed by Neurons cell body) inside (butterfly shape), and white matter (formed by axon) Outside.

The peripheral nervous SystemIt is made Of nerves is not protected by bones and is divided into:Somatic nervous system:It Carries Information of nerves that controls muscles that have conscious control. Autonomic nervous system:It carries Information of nerves that manage organs that have unconscious control, and is Divided in:Sympathetic: Act over organs in case of stress.Parasympathetic: act over organs in case of relaxation.