Neuromuscular Anatomy: Categories of the Nervous System

Hello :) In this post we'll be tackling neuromuscular anatomy. In our course, one of the major things we need to understand is how to define the categories of the nervous system, so that's what this post will cover. Enjoy!

Categories of the Nervous System

Before we start, it is important to understand that in reality the nervous system is integrated and forms a whole. However, it may be helpful to divide it up into parts. 

If we were to consider mainly structure and the relationship of the nervous system and to other body parts we could divide it into the Central and Peripheral Nervous systems (CNS and PNS, respectively). The CNS consists of the brain and spinal cord (sometimes called the neuraxis) while the PNS consists of the cranial, spinal and autonomic nerve trunks and their associated ganglia. 

Another way to categorise the nervous system would be to consider function. Using this method the nervous system (NS) can be divided into afferent and efferent systems. The afferent NS transmits nerve impulses to the brain and spinal cord while the efferent NS transmits impulses away from these. Within the PNS, afferent nerves are considered sensory while in the spinal cord they are considered ascending. This is because they conduct impulses from "lower" (caudal) to "higher" (cranial) areas of the CNS. In the PNS, efferent nerves are known as motor neurons while in the spinal cord they are considered descending. This is because they travel from cranial to caudal areas of the CNS. 

If we look at the type of information that is conveyed by the nerves we can categorise the nervous system in another way. The somatic system refers to the functions that determine the relationship of the organism to the outside world. The visceral system involves functions which relate to the internal environment. The visceral system also contains the autonomic nervous system which includes sympathetic and parasympathetic divisions which work antagonistically.

Below is a diagram which integrates these categories and sums them up nicely:

Even further divisions are possible, however none of these were mentioned in our lectures and so probably aren't that important for this unit so I won't describe them here. 

That's it for this post, let me know if you have any questions :)