Divisions of the Nervous System - Neuroanatomy Basics
Summary
TLDRIn this Anatomy Zone tutorial, Peter explores the nervous system's organization, distinguishing between the central (CNS) and peripheral (PNS) divisions. The CNS, comprising the brain and spinal cord, processes environmental information. The PNS, including cranial and spinal nerves, transmits sensory data and motor responses. Peter further breaks down the CNS into the forebrain, midbrain, and hindbrain, detailing their development and functions. He also explains the autonomic nervous system, highlighting its parasympathetic, sympathetic, and enteric components, which regulate involuntary body functions. The tutorial concludes with a discussion on sensory and motor nerve fibers, essential for conscious perception and voluntary muscle control.
Takeaways
- 🧠 The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS).
- 🌐 The CNS includes the brain and the spinal cord, which are responsible for complex information processing.
- 🔗 The PNS connects the CNS to peripheral structures through cranial and spinal nerves.
- 💧 Plexuses are networks of interconnected nerves that allow the redistribution of nerve fibers into different nerves.
- 🏢 Ganglia are collections of nerve cell bodies from the PNS, such as dorsal root ganglia and autonomic ganglia.
- 🧬 The brain can be broken down into the forebrain, midbrain, and hindbrain based on embryological development.
- 🧩 The hindbrain includes the medulla, pons, and cerebellum, each with specific functions.
- 🥼 The midbrain consists of the tectum and tegmentum, playing a role in visual and auditory reflexes.
- 🧠 The forebrain includes the telencephalon and diencephalon, which encompass the cerebral cortex and subcortical structures.
- 🔄 The PNS is divided into the somatic and autonomic nervous systems, with the latter further divided into parasympathetic, sympathetic, and enteric systems.
- 🔎 The autonomic nervous system is responsible for involuntary control of the body and maintaining homeostasis.
- 🏋️♂️ The somatic nervous system is responsible for conscious perception and voluntary motor responses.
- 🔮 Cranial nerves convey information related to the special senses such as taste, smell, vision, hearing, and balance.
Q & A
What are the two main divisions of the nervous system?
-The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and the spinal cord, while the PNS connects the CNS to peripheral structures.
What is the CNS responsible for?
-The CNS is responsible for complex information processing and serves as the control center for the body, where all environmental information is processed.
What are the main components of the PNS?
-The PNS consists of nerves that attach to the brain (cranial nerves) and spinal cord (spinal nerves), along with plexuses and ganglia.
What is the function of plexuses in the PNS?
-Plexuses are networks of interconnected nerves that allow the redistribution of different nerve fibers into different nerves.
What are ganglia in the context of the nervous system?
-Ganglia are collections of nerve cell bodies from the peripheral nervous system, such as dorsal root ganglia and autonomic ganglia.
How is the brain divided based on embryological development?
-The brain is divided into the forebrain (proenkephale), midbrain (mesenkephale), and hindbrain (rhombencephalon) based on embryological development.
What are the main parts of the forebrain?
-The forebrain consists of the telencephalon (cerebral cortex and subcortical structures) and the diencephalon (thalamus and hypothalamus).
How is the PNS further divided?
-The PNS is divided into the somatic nervous system (responsible for conscious perception and voluntary motor responses) and the autonomic nervous system (responsible for involuntary control of the body).
What is the autonomic nervous system responsible for?
-The autonomic nervous system is responsible for the involuntary control of the body, maintaining internal environment, and homeostasis.
What are the subdivisions of the autonomic nervous system?
-The autonomic nervous system is subdivided into the parasympathetic, sympathetic, and enteric nervous systems.
What is the difference between the parasympathetic and sympathetic nervous systems?
-The parasympathetic nervous system is involved in resting and digesting, while the sympathetic nervous system is involved in the fight or flight response.
How are peripheral nerve fibers functionally divided?
-Peripheral nerve fibers are functionally divided into sensory (afferent) and motor (efferent) divisions. Sensory fibers bring stimuli from the periphery to the CNS, while motor fibers result in skeletal muscle contraction.
Outlines
🧠 Nervous System Overview
Peter from Anatomy Zone introduces the tutorial on neuroanatomy basics, focusing on the divisions and organization of the nervous system. The nervous system is divided into the central nervous system (CNS), comprising the brain and spinal cord, and the peripheral nervous system (PNS), which connects the CNS to peripheral structures. The CNS is responsible for complex information processing and serves as the body's control center. The PNS, on the other hand, receives sensory information and sends out responses to peripheral inputs. The tutorial also explains the concept of plexuses and ganglia, which are networks of interconnected nerves and collections of nerve cell bodies, respectively. Additionally, the CNS is further divided into the forebrain, midbrain, and hindbrain, each with its own components and functions.
🔍 Divisions of the Peripheral Nervous System
This section delves into the subdivisions of the peripheral nervous system, highlighting the somatic and autonomic parts. The somatic nervous system is responsible for conscious perception and voluntary motor responses, controlling the contraction of skeletal muscles. In contrast, the autonomic nervous system manages involuntary body functions to maintain homeostasis. It is further divided into the parasympathetic (rest and digest), sympathetic (fight or flight), and the enteric nervous system, which controls the gastrointestinal system. The tutorial also discusses the functional divisions of peripheral nerve fibers into sensory (afferent) and motor (efferent) components, as well as the terms somatic and visceral to describe nerves related to skin, muscles, and internal organs.
👤 Special Senses and Cranial Nerves
The final paragraph discusses the inclusion of special senses like taste, smell, vision, hearing, and balance in the context of cranial nerves. It introduces the concept of general and special nerve fibers, with the latter conveying information related to these special senses. The tutorial uses a diagram to illustrate the concepts of visceral afferent and efferent nerve fibers, as well as somatic afferent and efferent fibers, which are related to touch receptors and skeletal muscle innervation, respectively. The summary wraps up with a brief encouragement for viewers to engage with the content and explore more videos on the channel.
Mindmap
Keywords
💡Nervous System
💡Central Nervous System (CNS)
💡Peripheral Nervous System (PNS)
💡Cranial Nerves
💡Spinal Nerves
💡Plexus
💡Ganglia
💡Forbrain
💡Hindbrain
💡Midbrain
💡Autonomic Nervous System
💡Somatic Nervous System
💡Afferent and Efferent
Highlights
The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS).
The CNS includes the brain and spinal cord, serving as the control center for processing environmental information.
The PNS connects the CNS to peripheral structures, receiving sensory information and sending responses.
Cranial nerves, mostly part of the PNS, attach to the brain, while spinal nerves attach to the spinal cord.
Plexus is a network of interconnected nerves that allows redistribution of nerve fibers.
Ganglia are collections of nerve cell bodies from the PNS, such as dorsal root ganglia and autonomic ganglia.
The brain can be divided into the forebrain, midbrain, and hindbrain based on embryological development.
The hindbrain further breaks down into the medulla, pons, and cerebellum.
The midbrain consists of the tectum and tegmentum.
The forebrain includes the telencephalon and diencephalon, with the diencephalon containing the thalamus and hypothalamus.
The telencephalon is the cerebrum, encompassing the cerebral cortex and subcortical structures.
The PNS is split into the somatic and autonomic parts, with the autonomic part further divided into parasympathetic, sympathetic, and enteric nervous systems.
The autonomic nervous system is responsible for involuntary control of the body and maintaining homeostasis.
The parasympathetic nervous system is involved in resting and digesting, while the sympathetic nervous system is involved in fight or flight responses.
The enteric nervous system controls smooth muscle and glandular tissue in the digestive system.
The somatic nervous system is responsible for conscious perception and voluntary motor responses, leading to skeletal muscle contraction.
Peripheral nerve fibers are functionally divided into sensory (afferent) and motor (efferent) divisions.
Sensory and motor components in the autonomic nervous system are also described as afferent and efferent.
Somatic nerves relate to skin and muscles, while visceral nerves relate to internal organs.
Cranial nerves include fibers for special senses such as taste, smell, vision, hearing, and balance.
Nerve fibers are categorized as general and special, with special senses being addressed in cranial nerve tutorials.
Transcripts
hi this is Peter from Anatomy Zone and
in this neuroanatomy Basics tutorial
we're going to take a look at the
divisions and the organization of the
nervous
system so the nervous system is divided
into the central nervous system and the
peripheral nervous system the central
nervous system consists of the brain and
the spinal cord and the peripheral
nervous system consists of those
structures which connect the central
nervous system to peripheral
structures so in this tutorial I'll
refer to the central nervous system as
the CNS and the peripheral nervous
system as the pns the CNS consists of
the brain and the spinal cord which you
can see in this diagram here so the CNS
is responsible for complex information
processing it is essentially our control
center where all the environmental
information is processed the peripheral
nervous system connects the central
nervous system to peripheral structures
it receives sensory information and also
sends out information to respond to this
peripheral
input so in this diagram you can see the
peripheral nervous system as extensions
from the central nervous system so the
pns consists of nerves which attach to
the brain and to the spinal cord so the
nerves which connect to the brain are
known as cranial nerves and I'm just
drawing these on here because it's not
represented in the diagram so the
cranial nerves are mostly part of the
peripheral nervous
system and then you can also see the
these nerves coming off the spinal cord
these are called spinal nerves and these
are also a part of the peripheral
nervous system so the cranial nerves the
spinal nerves and all their branches are
part of the peripheral nervous system
and just to point out while we're
looking at this diagram you've also got
things called plexuses so you can see up
here there's a network of interconnected
nerves this network allows the
redistribution of different nerve fibers
into different nerves and this
networking structure of peripheral
nerves is known as a plexus so the one
over here is the brachial plexus and
down here you can see another network of
nerves and this is the lumbo sacral
plexus and if you look to the side of
the spinal cord you can see these round
shaped structures these are the ganglia
so these ganglia are collections of
nerve cell bodies of the nerves from the
peripheral nervous system so examples of
these are the dorsal root ganglia and
autonomic ganglia
so before we move on let's just take a
look at the various divisions of the
central nervous system so as you know it
consists of the spinal cord and the
brain the brain can be broken down into
various different components based on
how it develops in embryological life so
what you've got is the forbrain the
midbrain and the hindbrain and
unfortunately they do have some
confusing names so the hind brain is
called the romen Keon the midbrain is
called the Meen Keyon and the for brain
is called the proen Keyon so it all
comes from Greek words now the hind
brain can be broken down further into
the myen Keyon and the meten keflon so
the myen keflon develops into the
medulla which you can see that I've
outlined in red the Met enlon forms the
pwns and the cerebellum and you can see
that I've outlined those structures in
blue
so the midbrain is referred to as the
Meen
keflon and the midbrain consists of the
tectum and the tegmentum and you can see
it highlighted here in this light blue
color now we're coming to the forbrain
which is known as the proen keflon and
this has two parts to it really it's got
the telen Keyon and the Dian Keyon what
we're looking at here is the Dian keflon
so in in the light green color you've
got the thalamus and in the orange color
you've got the high
hypothalamus so in this diagram what
we've done is we've taken A sagittal
section through the middle of the brain
so the telen cyon is essentially the
cerebrum which encompasses the cerebral
cortex and the subcortical structures
like the basil ganglia the hippocampus
and the amydala
so I've just outlined that in Red so
that's a brief run through the basic
anatomical organization of the central
nervous
system so having taken going a look at
the central nervous system let's return
to the peripheral nervous system and
look at how this is split
up essentially you've got two parts to
it you've got the sematic part and the
autonomic part so the autonomic part can
then be further subdivided into the
parasympathetic the sympathetic and the
enteric nervous system and within these
these components of the peripheral
nervous system you've also got sensory
and motor
divisions so the sematic IC nervous
system is responsible for conscious
perception and voluntary motor responses
so it's responsible for contraction of
skeletal
muscle the autonomic nervous system on
the other hand is responsible for the
involuntary control of the body so it's
involved in maintaining our internal
environment and maintaining homeostasis
it regulates that internal environment
and keeps everything under
control so to just talk about the
autonomic nervous system in a little bit
bit more detail autonomic comes from the
Greek meaning self-governing so Auto
means self and nomos means law what the
autonomic nervous system does is it
detects and monitors changes in the
activity of the viscera and it can help
to control
them it supplies and innovates things
like the cardiac and smooth muscle as
well as glands and their secretions so
as I mentioned before you've got some
subdivisions of the autonomic nervous
system and these subdivisions tend to do
opposite things to each other and in
this respect they're
antagonistic so the two main components
are the parasympathetic and the
sympathetic nervous system so the
parasympathetic nervous system is
involved in resting and digesting
whereas the sympathetic nervous system
is involved in the fight and flight
response so parasympathetic rest and
digest sympathetic fight and flight and
this is a broad generalization but it
helps you to get an idea of the function
so these divisions are distinct both fun
functionally and
anatomically the final division of the
autonomic nervous system the third
division Which is less talked about is
the enteric nervous system and this is
located in plexuses within the
gastrointestinal system and it's
responsible for controlling smooth
muscle and glandular tissue in the
digestive
system now just to come back to the
sematic nervous system this branch of
the peripheral nervous system is
responsible for conscious perception and
voluntary motor responses so this
diagram just shows how a peripheral
stimulus can be picked up and
transmitted along a neuron a sensory
neuron into the central nervous system
and then the central nervous system can
coordinate a response and cause sceletal
muscle contraction in response so the
sematic nervous system is responsible
for consciously processed information
that results in sceletal muscle
contraction now this brings me on to the
next division that we can make within
the nervous system so we've talked about
the different components of the
peripheral nervous system and now we can
talk about the peripheral nerve fibers
in terms of their functional divisions
so right here we can talk about the
sensory and motor divisions so the
sensory division of the peripheral
nervous system is known as the afferent
division whereas the motor component the
part which results in sceletal muscle
contraction is known as the efferent
division in this diagram the blue axon
represents the sensory division so this
is the division which brings the
stimulus from the periphery into the
center and the efferent division is
represented by this red neuron so this
red neuron is a motor
neuron so you've got this functional
division of neurons into sensory and
motor sensory are afferent motor are
efferent and in the monic for this is
the word same so s a m sensory afer
motor eant and how you remember whether
afren or ephant leaves or goes towards
the central nervous system is using the
pneumonic afferent arrives efferent
exits now in terms of the autonomic
nervous system you've also got sensor
and motor components or afferent and
efferent components so taking a look at
this diagram just to illustrate the
point we've got a sensory nerve ending
up here which is detecting some kind of
peripheral stimulus for example example
it could be detecting stretch in the
aortic or cored sinuses so stretch in
the smooth muscle wall of a blood vessel
and it feeds back into the central
nervous system and a response is
provided to relax the smooth muscle wall
so you've got a sensory component which
picks up that stretch in the coridor
aortic sinuses in the blood vessel wall
and then you've got a motor component or
an eant component which feeds back to
the blood vessel smooth muscle so that's
an example of afer and efferent
components in the autonomic nervous
system so sensory and motor
components other words used to describe
functional divisions in peripheral
nerves are somatic and visceral so
somatic just refers to skin and muscles
and visceral refers to nerves innovating
internal organs so there's a few words
now that we've used to describe the
functional divisions of peripheral nerve
fibers sensory and motor synonymous with
AFR and eant and now we've talked about
somatic and visceral relating to skin
and muscles and internal organs
respectively when you talk about cranial
nerves another element is thrown in you
actually have nerve fibers in the head
which convey information relating to the
special senses so now you've got taste
smell Vision Hearing and Balance thrown
into the mix and because you've got
these special Senses nerve fibers are
also divided into General and special
but we'll take a look at this in the
cranial nerve nerve tutorials so just to
put these examples into context let's
use this diagram here to combine those
words we've just talked about so this is
a nerve picking up a peripheral stimulus
for example in the from the blood vessel
wall this stretch receptors in a blood
vessel wall so this is visceral because
it's relating to blood vessels and it's
also bringing information into the
spinal cord so bringing it into the
center so it's an afen neuron this would
be called a visceral afren nerve fiber
now the nerve fiber leaving from the
center to innovate the smooth muscle
wall and cause relaxation or contraction
is called a visceral
eant so we've got a visceral affrant and
a visceral
eant now coming back to this diagram
we've got an affrant nerve fiber
conveying a peripheral stimulus from the
hand so from a touch receptor so this is
a sematic arrant and then you've got
this nerve fiber which begins in the
vental Horn of the gray matter of the
spinal cord and it innovates skeletal
muscle so this is a motor neuron and
it's eant so this is a sematic eant so
we've got a sematic affrant and a
sematic eant fiber or a motor
fiber so that's an overview of the
divisions of the nervous
system if you found this video helpful
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