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Nerves: Human brain, CNS and PNS


Human brain

{ from http://becuo.com/parts-of-the-brain }

eloquent areas of brain


The cortical homunculus

You taste, touch, smell, feel and hear – where do these sense affect your brain?

The cortical homunculus is the part of the brain responsible for processing and integration of motor information (muscles, motion) and tactile information (touch, senses)

The reason for the distorted appearance is that the amount of cortex is proportional to how richly innervated that region is, not to its size.

The resulting image appears as a disfigured human with disproportionately huge hands, lips, and face in comparison to the rest of the body.

{ http://en.wikipedia.org/wiki/Cortical_homunculus }


Sensory Homunculus Brain

CNS in pink = Central Nervous System

The central nervous system (CNS) controls most functions of the body and mind.
It consists of two parts: the brain and the spinal cord.
The brain is the center of our thoughts, the interpreter of our external environment,
and the origin of control over body movement.
Like a central computer, it interprets information from our eyes (sight), ears (sound),
nose (smell), tongue (taste), and skin (touch), as well as from internal organs such as the stomach.

The spinal cord is the highway for communication between the body and the brain.
When the spinal cord is injured, the exchange of information between the brain and
other parts of the body is disrupted.

{ http://www.christopherreeve.org/site/c.ddJFKRNoFiG/b.4434399/k.69DA/How_the_Spinal_Cord_Works.htm }


PNS in yellow = Peripheral Nervous System

The PNS is the set of nerves reaching from the CNS out to the rest of the body.

It sends information from the body’s sensory receptors to the CNS.
Once the CNS decided what to do about this information, it sends a signal back to the muscle or organ through the PNS.

Two main parts:

Sensory neurons: collects info from sensory receptors in areas like skin, muscles, and organs.

Motor neurons:  Sends commands from the CNS out to the body’s organs and muscles.

Motor neurons are divided into other sections, as shown on the graphic below.

2d (two-dimensional) view from http://en.wikipedia.org/wiki/Central_nervous_system

3D view of nerves in a human male

The central nervous system

The peripheral nervous system

Overview of the entire nervous system
The Nervous System overview the-autonomic-nervous-system
Sympathetic and parasympathetic nervous system

Sympathetic and parasympathetic nervous system

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