2.4.II  Ss e Ms  (Sensory and Motor systems)
In the CNS neurons are individual and relay neurons that are organized in 
such a way as to integrate a multitude of signals converging on them.  Fre-
quent throughout the CNS, the most important centre of retransmission is 
the thalamus, which thus consists of a set of nuclei, with different functions 
and receive sensory processing.
It is possible to make a distinction of SN in sensory system, motor system, 
the sensory component includes all cells and circuits that provide infor-
mation about the external or internal environment in the body, while the 
motor system includes all items in mobiles and the circuits that give rise 
to the movement. The sensory signal conducted by the SNP in the streets 
is picked up by the sensory receptor, then go from the spinal cord to the 
brain stem to the thalamus where it is processed and sent to the cortex 
celebrate. Instead the motor pathways or descendants are managed by 
bark mark, which decides the type of movement to accomplish and what 
posture should be taken. The main route is the corticospinal motor that 
originates from the bark celebrate, this bundle is in the brainstem until you 
reach directly to download on motor neurons, which control activity (in-
hibition or facilitation) on them, or causing contraction of specific muscle 
groups. In general you can say that the cerebellum is considered an organ 
essential for regulation of muscle tone, the planning and coordination of 
movements, and thanks to the presence of two efferent pathways (via 
cerebello-thalamus-crticale, via cerebello-cortical talamo-rubro-) sends to 
the cerebrum proprioceptive information about the State of distension of 
every muscle from recruit to a certain movement, operating in such a way 
that every muscle recruited there participate so fit for purpose and that the 
movement takes place gradually. However the cerebellum is considered 
the landmark motor tract has the role of programming the movements and 
motor learning. The body has sensors that are divided according to the 
type of sensitivity: esterocettiva and proprioceptive.
Sensitivity esterocettiva is a bridge between the human body and the out-
side world, and thanks to the presence of receptors located on the sur-
face, in the skin, in the mouth cavity and nasal cavity; they are sensitive 
13  Motor system
to tactile stimuli, pain and heat. Moreover, in addition to this, the body 
has highly specialized organs located in the head and responsible for 
vision, hearing, smell and taste (esterocettiva special somatic sensibi-
lities).
Proprioceptive sensitivity is activated with the body movements in re-
lation to changes in length or tension of the formations of the muscular 
system. It was born thanks to the presence of articular capsules in 
skeletal muscles and muscle-tendon junctions. Also a special organ in 
the inner ear (organ of the shoe) is responsible for a particular form of 
proprioceptive sensitivity, known as kinesthetic, which is triggered by 
changes in Chief positions. The sensory system previously introduced 
consists of: mechanical sensitivity, thermal sensitivity and anguished 
sensitivity. The mechanoreception or tactile sensitivity is mediated by 
mechanical receptors, with the function of providing the SNC informa-
tion on physical contact, the pressure, the tension and the presence 
of cutaneous vibrations. An important group of meccanorecettori are 
the proprioceptors that mediate motor activities, both reflected that vo-
lunteers. They constitute the kinesthetic sensibility that refers to the 
ability to sense the position of the joints, direction and  speed of their 
movement and to modulate the force required to hold or lift an object. 
The thermal sensitivity is characterized by (termocettori) receptors that 
respond specifically to thermal stimulations applied to the skin.
The anguished senibilità, instead, consists of receptors (nociceptors) 
that serve to alert the individual of a harmful event, so that he can pur-
sue a defensive response. In addition to the presence of cutaneous re-
ceptors, there are two other very important sensory systems: auditory 
and Visual system. The duties of the auditory system are basically two: 
acoustic signal recognition and recognition of the origin of the sound. 
The process of auditory signal processing is done by analyzing the main 
characteristics (height, intensity and timbre), the temporal sequence of 
sounds and the distance between sound and pause. All information 
received are projected to the auditory cortex, specifically in the area of 
13
2.4  Il Nervous system