2-Minute Neuroscience: Divisions of the Nervous System Video Lecture | A-Z Guide to Neuroscience - Personal Learning

Welcome to 2 minute neuroscience, where I
simplistically explain neuroscience topics
in 2 minutes or less.
In this installment I will discuss the divisions
of the nervous system.
There are two major divisions of the nervous
system.
The first is the central nervous system, which
is made up of the brain and the spinal cord.
The second is the peripheral nervous system,
which consists of nerves that run throughout
the body.
The peripheral nervous system itself is made
up of two subdivisions.
The first is the somatic nervous system, which
contains nerves that carry sensory signals
from the body to the central nervous system
and nerves that carry motor signals from the
central nervous system to skeletal muscles.
The somatic nervous system is associated with
voluntary movement.
When you clicked on this video to play it,
the signal to depress your finger was sent
from your brain to your finger via the somatic
nervous system.
The second division of the peripheral nervous
system is the autonomic nervous system.
The autonomic nervous system is sometimes
called the involuntary nervous system, and
it is involved in regulating the internal
environment of the body.
It carries signals from internal organs to
the central nervous system and from the central
nervous system to the internal organs.
In this way, it is involved in regulating
things like digestion and heartbeat, which
are generally outside the realm of conscious
control.
The autonomic nervous system can be further
subdivided into sympathetic and parasympathetic
nerve fibers.
The sympathetic nervous system plays a large
role in stimulating and mobilizing energy
resources, while the parasympathetic nervous
system acts to conserve energy.
For example, if you are in a frightening situation,
the sympathetic nervous system will cause
your heart rate to increase, your blood pressure
to increase, and your sweat glands to be stimulated.
If you are eating a meal, however, and are
not frightened, your parasympathetic nervous
system will stimulate digestion, increase
salivation, and slow your heart rate.
Due to these functions, the sympathetic nervous
system is often described as being involved
in fight or flight responses, while the parasympathetic
nervous system is described as being involved
in rest and digest responses.