-
[SOUND EFFECT]
-
SPEAKER: All right, ninja nerds.
-
So we've already covered
the brain in another video.
-
Our intention in
this video is just
-
to be able to give
you guys another view
-
of the brain and some of
the internal structures.
-
So let's go ahead and
dive right into this.
-
So first off, if you
remember from before,
-
we had this central
sulcus here on the side.
-
And it's just this
little groove right here,
-
running right there.
-
This guy right there is actually
called the central sulcus.
-
So again, the central
sulcus is this little groove
-
right here running all
the way up right there.
-
And what's the purpose of it?
-
The central sulcus
separates the frontal lobe
-
from the parietal lobe.
-
So if I come up
the central sulcus
-
one more time, if I go right
in front of this sulcus
-
to this gyrus right
there-- because remember,
-
sulcus is this little divot.
-
And then a gyrus is this big,
fat, lumpy thing right there,
-
right?
-
This gyrus in front
of the central sulcus
-
is called the precentral gyrus.
-
It's also where the
primary motor cortex is.
-
And if I follow the central
sulcus because back up again
-
and I go to this fat gyrus
that's right behind it,
-
that guy right there is
called the postcentral gyrus.
-
And that's where the primary
somatosensory cortex is.
-
All right?
-
And then if I were
to go in front
-
of the primary motor here, which
is where the precentral gyrus
-
is, I'd hit the premotor.
-
And then you come
in front of that,
-
and you hit what's called
the prefrontal cortex and so
-
on and so forth.
-
There's even called the
eyelids, stuff like that.
-
But again, basic
important thing right here
-
is central sulcus, precentral
gyrus, postcentral gyrus.
-
The precentral gyrus
is functionally
-
called the primary motor cortex.
-
The postcentral
gyrus is functionally
-
called the primary
somatosensory cortex.
-
OK?
-
Then if I were to continue
to work my way back
-
to see where else does
the parietal lobe--
-
where does that terminate,
and where does it
-
go to another lobe?
-
So if I come over
here, I'm going
-
to take this brain and kind
of, like, open it up here.
-
Turn it around.
-
So if we look here, you'll see
another sulcus right there.
-
That sulcus right
there is actually
-
called the parietal
occipital sulcus.
-
And the parietal
occipital sulcus
-
is what separates the parietal
lobe from the occipital lobe.
-
So back here is
the occipital lobe.
-
I'll give you guys another
view here in a second.
-
Just let me repeat that
one more time again.
-
This is the parietal
occipital sulcus.
-
And the parietal
occipital sulcus
-
is what separates the
parietal lobe, which
-
begins right after
the central sulcus,
-
all the way up to this sulcus.
-
And it separates the
parietal lobe, again,
-
from the occipital lobe.
-
All right, guys, so
if we look back here,
-
we have the occipital
lobe back there.
-
Again, and what separates
the occipital lobe
-
from the parietal lobe is the
parietal occipital sulcus.
-
Again, this is the
occipital lobe.
-
In the occipital lobe,
there is a specific cortex
-
that's actually called
the primary visual cortex.
-
And so that's where, you
know, the actual signal
-
transduction that comes from our
retina that portrays basically
-
light, we can actually
have the perception
-
of that light in this area to be
able to perceive what we see--
-
you know, certain types of
objects and shapes and colors
-
and so on and so forth.
-
So again, primary
visual cortex is located
-
within the occipital lobe.
-
And then if I turn
this to the right side,
-
our lateral side over here,
we can see another sulcus.
-
And this sulcus is right here.
-
Actually, let me move
rubber band, guys,
-
so we can see a little better.
-
If I move that rubber band
right there and I move my finger
-
right-- or this
little pointer here--
-
right through this area,
right through that sulcus,
-
that sulcus right there is
called the lateral sulcus.
-
Now, the lateral
sulcus is the sulcus
-
that separates the
temporal lobe, again,
-
from the parietal lobe
and even a little bit
-
from the frontal lobe.
-
But this lateral sulcus
runs right down here,
-
and it separates
the temporal lobe
-
from the parietal lobe
and even a little bit
-
from the frontal lobe.
-
So again, what is this
lobe right here then?
-
I already said, this
is the temporal lobe.
-
And the temporal lobe has
a specific cortex in it,
-
which is called the
primary auditory cortex.
-
And the primary
auditory cortex is
-
going to be where we
take specifically sound
-
and hearing from the
cochlea in our inner ear
-
and we bring it to this area
to be able to perceive and put
-
together different
types of memories
-
to understand what
we're hearing,
-
and we're able to perceive
that hearing, right?
-
All right, so that's where the
primary auditory cortex is.
-
Again, that's the temporal lobe.
-
There is another
lobe we can't see.
-
And it's going to be deep
to the temporal lobe,
-
and that's called the insula
All right, so let's go ahead
-
and show you two
more other areas that
-
are kind of important here.
-
And what I'm going
to do is it's only
-
on the left side of
the frontal lobe.
-
It's called the Broca's area.
-
So the Broca's
area is just going
-
to be this little area
over here on the left side
-
of the frontal lobe.
-
Again, it controls the
muscles of speech production,
-
so being able to change
the shape of our mouth
-
and other types of muscles
that are basically assisting
-
with pronunciation and
production of consonants
-
and so on and so forth.
-
But again, just controls the
muscles of speech production.
-
There's another area back here.
-
It's kind of an overlapping
area right around here.
-
That's called the
word Wernicke's area.
-
Basically he just helps us to
be able to understand what we're
-
hearing and put
those words together
-
in a appropriate manner
that when we speak it,
-
it makes sense.
-
OK?
-
So he does help with being
able to play a role also
-
in speech production but
also understanding speech.
-
All right, so that's
the Wernicke's area.
-
Now what I'm going to
do is we're actually
-
going to kind of take
this guy here and turn it
-
forward here so I can show
you another structure.
-
This whole thing up
here is the cerebrum.
-
And the cerebrum--
and it's actually
-
derived from what's called
the telencephalon, OK?
-
That's its scientific name.
-
But what I'm going
to do is I'm going
-
to kind of separate these two
cerebral hemispheres right
-
there.
-
And what happens is
there's a fissure that
-
runs right between these two--
-
right between these two.
-
And that's called the
longitudinal fissure.
-
Called the longitudinal fissure.
-
Why I mentioned that
is there's what's
-
called dural sinuses
that are veins
-
that run through this area,
and we have to protect them.
-
So there's these things called
dural septum, which are just
-
little septal partitions
of dural matter
-
that dip down into this
longitudinal fissure
-
and protect the dural sinuses.
-
And that dural septa that comes
in here in the longitudinal
-
fissure is called the
falx, F-A-L-X, cerebri.
-
So falx cerebri.
-
And again, it's right here
in the longitudinal fissure.
-
All right, now I'm going to go
ahead and turn this guy around
-
so we can tell you
guys about another one.
-
So I'm going to
come back here, back
-
where the occipital lobe was.
-
And if you remember, this was
the occipital lobe, right?
-
Well, how do we know-- we know
where the parietal lobe is.
-
You remember, it starts
at the central sulcus,
-
and then it ends at the
parietal occipital sulcus.
-
And that's where the
occipital lobe begins,
-
at the parietal
occipital sulcus.
-
Where does it end?
-
It ends right back
here where there's
-
this little space in here right
between the occipital lobe
-
and the cerebellum right there.
-
So in between here is what's
called the transverse fissure.
-
And the transverse
fissure is important
-
because there's another
dural septa that
-
actually dips in that area.
-
And that right there is called
the tentorium cerebelli.
-
Cerebelli, OK?
-
Tentorium cerebelli.
-
And it's just a dural
matter partition or septa
-
that dips in that area.
-
OK?
-
Now what we're
going to do is we're
-
going to go ahead deeper into
the structures of the cerebrum
-
and take a look at that, OK?
-
All right, guys, so now
what I'm going to do
-
is I'm going to show
some other structures
-
underneath the cerebrum.
-
So deep in the cerebrum--
-
I just want to show you guys.
-
If you see all this white right
here, this is all white matter.
-
And what white matter is, is
it's just myelinated axons.
-
So it's myelinated axons.
-
And myelinated
axons just means it
-
has this thing
called myelin, which
-
is made up of fat and proteins.
-
It helps with basically
nerve conduction,
-
the speed of nerve conduction.
-
But anyway, myelinated
axons right here
-
is going to be the white matter.
-
All this pink stuff around the
edges or the outsides of it,
-
this is all part of what's
called our cerebral cortex.
-
And that's made of gray matter.
-
And gray matter is actually
unmyelinated cell body.
-
So there's no myelin
around the cell bodies.
-
OK?
-
So unmyelinated cell bodies
is our gray matter, which
-
makes up the cerebral cortex.
-
You can think of that like
as the thinking tissue.
-
So that's the part where they're
the biomechanical centers,
-
and they basically--
-
they're the ones that
control a lot of the thinking
-
or conscious thought.
-
This white matter, you
could think of that
-
as like transmission tissue.
-
It's basically responsible for
being able to transmit impulses
-
to and from certain areas.
-
OK?
-
So again, that shows
you the cerebral cortex
-
and, again, shows you the
white matter right there.
-
Now what we're
going to do is we're
-
going to take a look at
some other structures, which
-
is in the diencephalon
and the ventricles.
-
All right, guys, I have the left
cerebral hemisphere right now.
-
What I'm going to
do is I'm going
-
to take this top piece off
so we can take a deeper look
-
at some structures inside here.
-
All right, so if we
take a look in here,
-
right now we're kind of
in the lateral ventricle.
-
And ventricles are
just basically cavities
-
within the actual brain and
also within the brain stem.
-
And it contains what's
called cerebral spinal fluid.
-
And we'll talk about that more
in the neurophysiology stuff.
-
But if you look
right here, sitting
-
in the bottom of the
lateral ventricle down here,
-
this is actually-- if you
remember from the other video,
-
it's called the hippocampus.
-
And the hippocampus
is a limbic nuclei.
-
So it plays a role with
memory and emotions
-
and so on and so forth.
-
So it does play a very,
very important role
-
within, basically, memory.
-
If you look here, that's 190.
-
And if I come up here and
I follow these white fibers
-
like 186--
-
if I follow it all
the way from here,
-
all the way back, and then
I come back up this way--
-
so again, all the way up
here, following this guy,
-
and all the way back this way.
-
These fibers are very important.
-
They're called
association fibers.
-
And association
fibers are what allow
-
for the movement of
impulses to go from front,
-
from in front of the cerebrum
to the back of the cerebrum
-
or vice versa.
-
OK?
-
So again, these are
association fibers,
-
and this is the hippocampus.
-
And then this whole
cavity right here--
-
so like, for example,
this is the inferior horn.
-
This is the posterior horn.
-
And then we'll see the
anterior horn in a second.
-
That's all the
lateral ventricle.
-
OK?
-
And again, you can
see the white matter.
-
And then you can see the
gray matter out there.
-
So the last structure here
is going to be number 206,
-
and this is actually called
the internal capsule.
-
And the internal capsule
is actually specific fiber.
-
It's called a projection fiber.
-
And projection fibers
are important for being
-
able to bring sensory
information up
-
to the cerebral cortex, OK?
-
So they bring information
up, all right?
-
But they do-- they can allow
for information to go down also.
-
So they just basically offer
movement to go up and down.
-
So association is back and
forth, so back and front,
-
back and front.
-
And projection is up
and down, up and down.
-
And we'll look at another
one in a second called
-
the commissural fibers.
-
All right?
-
Now we're going to go ahead
and turn it around and look
-
at some other structures, guys.
-
All right, so I just
turned it around, guys.
-
So again, we're looking here
at kind of like the other view.
-
I was on the back side.
-
Now we're looking over
here on the front side.
-
So if you look right here,
there's a nuclei right here.
-
It's a basal nuclei.
-
And basal nuclei just
are important for being
-
able to dampen or smooth
out certain motor movements.
-
He's one of them.
-
He's called the caudate nucleus.
-
So that's the caudate
nucleus right there.
-
But this whole-- remember I told
you there was another anterior
-
horn of that lateral ventricle.
-
So there's a little cavity here.
-
And this whole cavity right
here is the lateral ventricle.
-
And if you look right here,
this structure right there
-
is actually called the-- it's
a choroid plexus, because there
-
is a choroid plexus,
which is basically
-
made up of ependymal
cells and pia mater.
-
And you're also going to have
your capillaries in there,
-
and it's what helps to be able
to make the cerebrospinal fluid
-
and circulate it.
-
So again, this is going to
be the lateral ventricle,
-
this cavity here.
-
Imagine it, like, bathing
this nucleus here.
-
Imagine it bathing
this caudate nucleus.
-
And imagine this
whole cavity filled
-
with cerebrospinal
fluid, and that's
-
made by this thing called
the choroid plexus.
-
And then you can see
this fiber right there.
-
There's another
white matter fiber,
-
and this is actually
called the fornix.
-
And the fornix is a white
fiber that actually-- it's
-
a tract, which is
a bundle of axons
-
in the central
nervous system that
-
connects multiple
limbic nuclei together.
-
So again, this
structure right here,
-
all the way from here,
all the way from here,
-
this is called the fornix.
-
And the fornix is
basically what helps
-
to be able to connect multiple
limbic nuclei together.
-
So again, last time,
lateral ventricle,
-
caudate nucleus, choroid plexus
of the lateral ventricle,
-
and the fornix.
-
All right, so now we're
going to go ahead and look
-
at some of these other
structures in the diencephalon.
-
All right, guys,
so this is right
-
here is the corpus callosum.
-
And the corpus callosum
number 145 here,
-
this is actually going
to be made up of what's
-
called commissural fibers.
-
And commissural fibers
are just, again,
-
myelinated axons that allow
for transmission of impulses
-
from left cerebral
hemisphere to right
-
or from right
cerebral hemisphere
-
to left cerebral hemisphere.
-
So it's very important
for that connection.
-
It's also an area
that's commonly
-
damaged during concussions.
-
And it's actually
been found that women
-
have more commissural
fibers than men do,
-
which allows for them to be able
to have a little bit better--
-
be better at multitasking
and stuff like that.
-
And it also plays a role in
epilepsy and stuff like that,
-
but we're not going
to get into that.
-
So again, corpus callosum there.
-
If you look here,
there's a membrane 146.
-
So this thin membrane here is
called the septum pellucidum.
-
And underneath the
septum pellucidum
-
is that lateral ventricle that
I was showing you guys before.
-
So underneath this
septum pellucidum
-
is the lateral ventricle.
-
OK?
-
So it's just a thin membrane
that separates the two
-
lateral ventricles.
-
Because, again, we have
a lateral ventricle
-
in one cerebral hemisphere.
-
Let's say the right one.
-
And we'll also have
a lateral ventricle
-
in the left cerebral hemisphere.
-
And the structure separating
them, this membrane,
-
is the septum pellucidum.
-
If you guys look at the
ventricle model we have,
-
you'll also see a better
way of looking at that also.
-
All right, let's
come back here again.
-
148 here, this is the fornix.
-
And again, that was
that fiber tract
-
that connects a lot of the
limbic nuclei together.
-
If I imagine I draw
a whole circle--
-
say I do a whole circle
all the way around here
-
or you imagine like an egg.
-
An egg is kind of like
oval-shaped, right?
-
So this whole thing right
here is the thalamus.
-
So this whole egg structure here
with a whole bunch of nuclei
-
is the thalamus.
-
And the thalamus is
actually the relay station
-
for a lot of sensory information
going up into the cerebrum,
-
because he has tons of nuclei
that regulate that activity.
-
Then if you look there, that
little brown structure right
-
there, that's called
the intermediate mass.
-
And it basically is like
an interthalamic adhesion
-
between the two
thalami, because you
-
have a thalamus in your
right cerebral hemisphere,
-
and you have a thalamus in
your left cerebral hemisphere.
-
So you have two of them.
-
If you actually imagine here--
-
imagine this being an
eye, like a bird's eye.
-
OK?
-
So if you can imagine it, you
can imagine the bird's eye,
-
which is kind of like
the white of the eye
-
is like the thalamus.
-
And then the pupil
right there is
-
where the intermediate mass is.
-
And if you imagine the
bird's beak right there,
-
this right there,
that bird's beak
-
is actually the hypothalamus.
-
So they can kind of say look
at the bird's eye and a bird's
-
beak.
-
And again, the
bird's eye is made up
-
of the thalamus and
intermediate mass.
-
And the bird's beak
is the hypothalamus.
-
If you look back
here, you have what's
-
called the pineal gland, which
is a part of the epithalamus.
-
Then you're also going
to notice this little--
-
the hypothalamus has
this little stalk
-
here on this side that connects
to the pituitary gland that
-
would sit right underneath
the optic chiasma.
-
Actually, this is-- if you
look at 170 there, that's--
-
where the optic nerves
cross, there's actually
-
called the optic chiasma.
-
So for example, this
is the right cerebrum,
-
so this would be the
right optic nerve here.
-
And it's getting ready--
some of its fibers
-
will cross over
to the left side.
-
OK?
-
So that's kind of like
the optic chiasma there.
-
And then this part right
there is the infundibulum.
-
But if you look right
there, that little,
-
like, ball there,
that right there is
-
called the mammillary bodies.
-
And the mammillary
bodies are also
-
important because they play
a role within certain types
-
of olfactory pathways.
-
So they play a role in smell.
-
That's the mammillary bodies,
and they're limbic nuclei.
-
So they play a role in
recollective memory,
-
stuff like that.
-
OK, if you come over
here, we're going
-
to see some other structures.
-
Now we're getting ready to
start moving into the brainstem.
-
So as we get ready
to move over here,
-
let's actually
hit our brainstem.
-
So if you look right here,
all this part right here,
-
this is all called the midbrain.
-
And they also call
it the mesencephalon.
-
So it was derived
from mesencephalon.
-
All this right here is our pons.
-
This is all our pons.
-
And the pons-- and this
right here is the cerebellum.
-
They were actually
derived from what's
-
called the metencephalon.
-
And then if we look here,
all the way over here,
-
this is the medulla oblongata.
-
And the medulla oblongata
was derived from what's
-
called the myelencephalon.
-
So again, I'll hit
it one more time.
-
Mesencephalon.
-
And then you got your
metencephalon, which is made up
-
of pons, and the cerebellum.
-
And then you have
your myelencephalon,
-
which is the medulla oblongata.
-
All right?
-
OK.
-
Another thing here is-- oh, I
also mentioned it a little bit
-
before.
-
I had mentioned that
all this area right here
-
is the diencephalon.
-
The diencephalon
is mainly made up
-
of three things, which we
said thalamus, hypothalamus,
-
and then technically
the epithalamus, which
-
consists of the pineal gland.
-
There's this little
cavity right here
-
that also contains
cerebrospinal fluid,
-
and this is called
the third ventricle.
-
So the third ventricle
would be a cavity right
-
in this vicinity right here.
-
So it actually gets drained
from the lateral ventricle.
-
So here's our third ventricle.
-
The third ventricle
actually drains
-
some of that actual fluid
from the lateral ventricle.
-
Then there's another little tube
right here running right here
-
through the midbrain.
-
So see that little
tube right there?
-
That's actually called
the cerebral aqueduct.
-
So the cerebral aqueduct
drains the third ventricle,
-
and the third ventricle
drains the lateral ventricle
-
via what's called the
interventricular foramen.
-
So again, third ventricle here
and then cerebral aqueduct
-
here.
-
Then the cerebral
aqueduct moves into what's
-
called the fourth ventricle.
-
And then from the
fourth ventricle,
-
the cerebrospinal
fluid can go two ways.
-
It can go down through
the central canal.
-
It will eventually go
through the central canal
-
of the spinal cord
or it can go out
-
through these two little holes
called the foramen Luschka
-
and the foramen Magendie.
-
Or you can say foramen Magendie
is the median apertures,
-
and the foramen Luschka
is the lateral apertures.
-
OK?
-
So that's that part there.
-
OK.
-
Now, if we look here in
the back of the midbrain,
-
we see these two little,
like, balls there.
-
All right?
-
This top one right there is
called the superior colliculi.
-
And basically what he helps you
to do is being able to move--
-
it's like a reflexive movement
of your head in response
-
to some type of visual stimulus.
-
For example, if I see
Kate Upton walking by,
-
my head is going to
move with response
-
to that visual stimulus.
-
Mm-mmm!
-
And then down here is
the inferior colliculi.
-
The inferior colliculi actually
controls reflexive head
-
movements or responds
to auditory stimulus.
-
So for example, if Kate Upton's
boyfriend yelled at me, hey,
-
what you doing looking
at her, my head
-
would move that way too.
-
So that's an example
of that right there.
-
OK, so superior colliculi,
inferior colliculi there.
-
All right, so if
I look here, guys,
-
there's another structure
I want to show you.
-
It's 182 right there.
-
That structure right there is
called the cerebral peduncles.
-
So it's like this stalk.
-
And again, these are
projection fibers actually.
-
So if you remember,
the cerebral peduncles,
-
these are projection fibers.
-
They're right
around the midbrain.
-
And they carry
sensory information up
-
into the cerebrum, OK?
-
So again, that's the cerebral
peduncles right there.
-
All right, guys, so if we look
here, I have 183 right there.
-
This is the pyramids.
-
This is the pyramids of
the medulla oblongata.
-
That's where the descending
motor fibers actually
-
decusse, or cross, right there.
-
OK?
-
So the pyramids is due to the
decussation, or just crossing,
-
of the descending
motor pathways.
-
All right, guys, so
if we look over here
-
on the side of the
medulla oblongata,
-
like, on this side of
this, all this pink gummy
-
stuff, that's all the olives.
-
And the olives are actually
broken up into two nuclei.
-
You've got their
superior olivary nuclei
-
and inferior olivary nuclei.
-
And the superior,
basically, they
-
play a role in basically
the auditory pathways.
-
And the inferior
olivary nuclei play
-
a role within proprioception
and cerebellum motor function
-
and learning and
stuff like that.
-
OK?
-
So again, olives play a
role in proprioception,
-
and they play a role
basically in hearing also.
-
All right?
-
So that's your olives.
-
Now what we're
going to do, guys,
-
is we're going to basically
go over the cerebellum now.
-
All right, guys, so if you look
here, you can see all of this,
-
like, tree-like
structure right there,
-
all this white, like,
tree-like-looking thing.
-
All this white matter here
is called the arbor vitae.
-
And the arbor vitae is just
basically the white matter
-
of the cerebellum.
-
arbor vitae actually stands
for, like, tree of life.
-
So again, all this white
matter here is the arbor vitae.
-
And the outer gray matter
on the actual edges
-
where you'll find, like,
your Purkinje cells
-
and certain stuff like
that, all the outer side
-
is the gray matter of
the cerebellar cortex.
-
And again, that's just
unmyelinated cell bodies.
-
Again, if you look here, in
the back of the cerebellum
-
here, if you see all
these little divots there,
-
it's actually called folia.
-
So the folia are basically like
the folds of the cerebellum.
-
OK, so all these little
lines right there
-
that you see forming
these little folds,
-
that's called the folia.
-
All right, guys, if you
look right here, right in
-
between the actual
cerebellum, there's
-
actually this little worm-like
structure between them.
-
It's actually called the vermis.
-
And in between the vermis,
there's an actual dural septa,
-
like I said before, that
actually runs in between there.
-
And that dural septa is actually
called the falx cerebelli.
-
The falx cerebelli.
-
OK, again, so this structure
right there between the two
-
cerebellum is the actual vermis.
-
And the dural septa that
goes between the two
-
is actually called
the falx cerebelli.
-
All right, so that pretty
much covers the cerebellum.
-
Now what we're
going to do is we're
-
going to move on to
the cranial nerves.
-
So if we look right here, we're
going to see cranial nerve one.
-
That's the olfactory nerve.
-
And again, remember that the
olfactory nerve originates
-
in the nasal cavity through
the olfactory epithelium,
-
and that actually picks up
certain types of sensations
-
like smell from odorants in
different types of chemicals
-
and carries that up
through the cribriform
-
plate of the ethmoid
bone and then up into--
-
specifically up into
this olfactory bulb here
-
where there's glomeruli
and mitral cells.
-
OK, so he's a sensory nerve.
-
Then right here, you're going
to notice two optic nerves right
-
there.
-
So there's your
left optic nerve.
-
There's your right optic nerve.
-
And then the point
in which they cross
-
is called the optic chiasma.
-
OK?
-
And so the optic nerve is--
-
basically picks up
sensations of vision.
-
So he picks up the
vision stimulus
-
and then takes that into
the actual cerebrum,
-
specifically to that
primary visual cortex.
-
Then we're going to have
to go and separate this guy
-
so we can look at some
other structures here,
-
so we look at the midbrain
a little bit deeper.
-
All right, guys,
so if we look here,
-
we can see cranial nerve 3.
-
It actually comes out in between
the interpeduncular fossa
-
right there at the midbrain.
-
That's called the oculomotor
nerve, cranial nerve 3.
-
The oculomotor
nerve actually runs
-
through the superior
orbital fissure
-
and supplies a lot of the
extraocular eye muscles.
-
I also didn't mention the
hole that the optic nerve runs
-
through, but you can imagine
it's the optic canal.
-
So again, oculomotor nerve runs
through the superior orbital
-
fissure and supplies a lot
of extraocular eye muscles.
-
Then if we come down here,
we can see this little--
-
you see this little white
thing right there, guys?
-
The little white piece of
thing popping down there?
-
That's called the
trochlear nerve.
-
So that's called trochlear
nerve, or cranial nerve 4.
-
And the cranial nerve 4,
or the trochlear nerve,
-
actually runs also through
the superior orbital fissure
-
and supplies the--
-
it's called the
superior oblique muscle.
-
It's just another
extraocular eye muscle.
-
OK, so he plays a role
in motor functioning.
-
All right, so here's the
trochlear nerve again, right?
-
So that's cranial nerve 4.
-
And then if you look down
here, we have these two nerves,
-
because they're paired, guys.
-
So we're going to see the
trigeminal nerve here,
-
which is cranial nerve 5.
-
And you'll see the
trigeminal nerve here,
-
which is, again,
cranial nerve 5.
-
So the trigeminal nerve
is a really big one,
-
and it actually splits
into three branches.
-
And it actually runs
through three holes.
-
It can run through the
superior orbital fissure.
-
It can run through the foramen
ovale and the foramen rotondum.
-
And the trigeminal nerve
supplies the muscles
-
of mastication, and
he also supplies
-
certain areas of the skin of
the face to pick up sensations.
-
So he plays a role in muscle
action, which is mastication,
-
chewing.
-
And he also picks up
sensations on the face.
-
Interestingly,
this is actually--
-
if this has what's
called neuralgia,
-
trigeminal neuralgia,
where there's
-
some certain type
of nerve pain, this
-
can cause one of the most severe
nerve pains actually known
-
to man.
-
It's actually called
trigeminal neuralgia.
-
And it's extremely,
extremely painful.
-
They actually call it
the suicide . disease.
-
All right, then if we come
down here to this structure
-
right there and that
structure right there,
-
these are actually your cranial
nerve 6, or the abducens nerve.
-
And he also runs through the
superior orbital fissure.
-
And he supplies
the lateral rectus.
-
And again, that's another
extraocular eye muscle.
-
Then if we move out
laterally over here,
-
we're going to have these
two guys-- see this one right
-
there and this one over here.
-
That's actually called
the facial nerve.
-
So that's cranial nerve 7.
-
So this one right there and
this one right there, OK?
-
And the facial nerve
has five branches.
-
But he can run through
the stylomastoid, foramen.
-
And he also can run through
the internal acoustic meatus.
-
But basically he supplies the
muscles of facial expression,
-
a lot of glands within the--
like the lacrimal gland
-
and nasal glands
and stuff like that.
-
So he plays a role in both--
-
and he also picks up sensations
again from the face as well.
-
So he's actually a motor
nerve and a sensory nerve.
-
OK?
-
So that's the facial nerve.
-
Then if we go over
here to the edge,
-
that one right there over
there and this one right there
-
on that edge, that is actually
called the vestibulocochlear
-
nerve.
-
And the vestibulocochlear
nerve, he also
-
runs through the
internal acoustic meatus.
-
And he basically carries dynamic
and static equilibrium and just
-
general sound and hearing.
-
And that's that guy.
-
Then if we come
down here, there's
-
this little chunk
right there, which
-
is the same chunk right there.
-
That's called the
glossopharyngeal nerve,
-
which is cranial nerve 9.
-
And he actually runs
through the jugular foramen,
-
and he supplies the tongue.
-
He supplies certain
muscles of the pharynx.
-
He also can act as-- he
can pick up sensations
-
from the baroreceptors.
-
So he plays a lot of roles in
different sensory and motor
-
functions as well.
-
OK?
-
Below him is the vagus nerve.
-
So this one right there
and this one right there.
-
That's cranial nerve 10.
-
So again, vagus nerve right
there and right there.
-
He is the main
parasympathetic nerve, OK?
-
He carries about 90% of
the parasympathetic flow.
-
And he also runs through
the jugular foramen,
-
and he supplies many,
many different organs
-
from the heart to the
lungs to the GI tract
-
to the urogenital tract,
so on and so forth.
-
So again, that's
your vagus nerve.
-
So if you look down
here, guys, you'll
-
see this nerve right
here and over here.
-
It's cranial nerve 11, which
is called the accessory nerve.
-
Now, the accessory
nerve has two parts.
-
One of them actually
is on the cervical part
-
of the spinal cord and
one on this medulla
-
here, like the medullary branch.
-
And what happens is the cervical
branch of the accessory nerve
-
comes up through
the foramen magnum
-
and merges with this
branch off the medulla.
-
And as a collection, they run
through the jugular foramen.
-
And they go and supply
the trapezius muscle
-
and the
sternocleidomastoid, which
-
are, again, those somatic
muscles or skeletal muscle.
-
All right, so that's
the accessory nerve.
-
So he's mainly a motor nerve.
-
And then the last one right
here is this guy right there,
-
which is the same as
this guy right there.
-
And that's cranial nerve 12,
which is the hypoglossal nerve.
-
And the hypoglossal
nerve actually
-
runs through what's called
the hypoglossal canal
-
and supplies some of
the extrinsic muscles
-
of the tongue.
-
OK?
-
So he's mainly a motor nerve.
-
All right, guys,
so that pretty much
-
covers all the cranial nerves.
-
I hope this video helped, guys.
-
And see you, ninja nerds.