Autonomic Nervous System Essay

The Autonomic Nervous System

Over tens of millions of years of evolution, the human body has effectively become one of the most intricate and advanced mechanisms that mankind has ever discovered. It has developed natural abilities and functions that continue to astonish the science community everyday. One of the most awe-inspiring structures found within the human body is the autonomic nervous system, which is largely responsible for regulating physiological processes and maintaining an essential homeostasis within the body in order for it to survive. The autonomic nervous system controls all of the functions human bodies perform unconsciously, or automatically, and without its help, people would not be able to walk, eat, or even breathe.

The sympathetic system is often called the fight or flight system, as it is the portion of the autonomic nervous system that is responsible for preparing the body for action and response. The parasympathetic system is sometimes called the rest and digest system due to the fact that it is responsible for slowing down the heart rate and stimulating the digestive system in order to process food and waste. So when the sympathetic system responds to the body 's need to run, it quickly sends messages to blood vessels to constrict, causing a rise in blood pressure so that oxygenated blood being pumped from the heart can reach actively engaged muscles more quickly. But once the body comes to a stop, the parasympathetic system begins sending messages for blood vessels to dilate and return the blood pressure to a regular level. This is just one instance where the parasympathetic system counterbalances the sympathetic, but a few other examples include when the sympathetic system dilates the airway and the pupils, decreases saliva production, and contracts sphincters, the parasympathetic system constricts the airway and pupils, increases saliva production for digestion, and relaxes the body 's sphincters ("Parasympathetic vs Sympathetic Nervous System."). There are also instances when each of the system 's independent effect on an organ are required to produce a desired bodily function, such as how the sympathetic system stimulates orgasm in males, while the parasympathetic system first stimulates an erection. These two divisions of the autonomic nervous system also differ in the rate at which they impact the body, as sympathetic processes generally occur very rapidly when compared to parasympathetic processes. For example, when a person becomes suddenly frightened while watching a scary movie, the sympathetic