Somatic and Autonomic Nervous Systems

Within the peripheral nervous system, there are 2 subdivisions: The Somatic and Autonomic nervous systems. These 2 are have opposite functions but both come in the same importance for your survival. Here's more...

The Somatic Nervous System

The Somatic nervous system (SNS) is all the nerves that connect to your skeletal muscles and control voluntary muscle movements including the movement of all sensory organs. The SNS’s job could be as simple as moving your arm up and down. It sends electrical and chemical messages from the brain to the skeletal muscles that needs to be moved based on information about your environment (known as stimuli). 

Almost all of the action that the somatic nervous system does is voluntary, but there are exceptions. These are known as reflex arcs. A muscles will move in response to stimuli without much activity in the brain, and almost no voluntary control. This is when your peripheral nerve and axon pathways only reach until your spinal cord. Just like the action of pulling your hand away from something hot. 

As a result of diseases and injuries to the spinal cord, the somatic nervous system will not be able to control parts of your body. Paraplegia is the term given for paralyzed legs due to damage to your lower spinal cord (damage in that area terminates transmitting signals which results in no control). Quadriplegia is the term given for the paralysis of all 4 limbs consequently to upper spinal cord or neck damage.

The autonomic nervous system 

The autonomic nervous division (ANS) is another main sub division of your periphery and plays a huge role for your survival. It is in charge of all involuntary actions, like your heart rate, basic reflexes, breathing and other movements or actions that you cannot really control. It sends impulses from the center of the brain (the diencephalon area) to many major involuntary areas such as the heart, lungs, and even blood vessels (for altering blood pressure). The main regions of the brain which control these involuntary actions include: The hypothalamus (in the diencephalon), the medulla, and the pons areas (both medulla and pons located within the brain stem). 

Looking further into the autonomic nervous system, there are 2 more divisions! They are well known as the sympathetic and parasympathetic systems. These 2 major components of the ANS prepare us for action and rest. The nerves from both systems carry impulses from sensory organs, to the 3 regions (hypothalamus, medulla, and pons). 

The sympathetic nervous system gets us ready for activity. It includes the command of your adrenal glands to produce adrenaline, meaning that it gets us ready for the famously known "fight or flight" type situations. Operating through a series of interconnected neurons, the sympathetic system also controls eye dilation (enlarging it), increasing heart rate + blood pressure, and contracts our bladder before while we get involved with a motion activity, lessening the urge to urinate.

As the sympathetic system is important for our survival in fight related situations, our parasympathetic system is also vital in our lives. It is responsible for healing/resting. This systems also acts through connections between nerves and organs; nevertheless, unlike the sympathetic system, its sensory signals are consciously received. Functions include contracting your eyes, lessening heart rate (therefore lessening breathing and blood pressure), and dilating your bladder, increasing the urge to pee!

Diseases that the ANS is responsible for includes...

• High blood pressure levels
• difficulty in breathing
• Heart problems and etc.