00:00:07
all right Niners what we're going to do
00:00:08
in this video is we're going to talk
00:00:09
about te- cell development all right
00:00:12
before we do that let's understand where
00:00:14
is the actual te- cells being made okay
00:00:18
so if we look here in this diagram just
00:00:19
give you kind of a look at the
00:00:20
anatomical structures here we're going
00:00:22
to have our red bone mirror here where
00:00:24
the actual tea cells are being produced
00:00:27
and then we're going to have our blood
00:00:28
vessel which is going to be our
00:00:29
sinusoidal capillaries that they could
00:00:30
be pushed into but then we're going to
00:00:32
take this what's going to happen is
00:00:34
we're going to follow this t- cell over
00:00:36
here into this blue structure right here
00:00:37
which is called the thymus gland right
00:00:39
and then we got the thymus gland uh
00:00:41
specifically we'll talk about this in
00:00:43
just a second actually we'll come back
00:00:44
to this but again what we're going to
00:00:46
need to know is that the te- cells are
00:00:47
produced within the red bone marrow and
00:00:50
then what's going to happen is they're
00:00:51
going to have to get sent to a primary
00:00:53
lymphoid organ which is called the
00:00:54
thymus gland where they're going to be
00:00:56
able to mature and undergo specific
00:00:58
types of selective processes which we'll
00:00:59
explain in detail all right so let's go
00:01:01
ahead and dive right into this right so
00:01:03
we have here in the red bone marrow if
00:01:05
you remember we had that lymphoid stem
00:01:07
cell and when it went over to all these
00:01:09
different types of Divisions It produced
00:01:11
your B cells and your t- cells let's
00:01:13
follow our T cells out of here so let's
00:01:16
say right here I have this t- cell right
00:01:20
here so this is our t- cell but it's
00:01:22
going to be kind of like a precursor so
00:01:24
this is our t- cell but it's like a
00:01:26
precursor t- cell so it's not completely
00:01:28
mature yet it's it's not at the point
00:01:30
where we can actually put that thing
00:01:31
into specific secondary lymphoid organs
00:01:34
and we'll talk about that so what
00:01:36
happens is this t- cell it's going to
00:01:38
get put into the bloodstream but how
00:01:41
does it know to go to the thymus gland
00:01:43
that's what's going to be cool so if we
00:01:44
come over to the thymus gland for a
00:01:46
second so here again this is our thymus
00:01:48
gland and where would we find the thymus
00:01:51
gland the thymus gland is actually
00:01:53
located it overlies the heart so it's
00:01:56
located within this mediastinum right
00:01:58
which is like a cavity that's located
00:02:00
within the thoracic cavity right and it
00:02:02
houses the esophagus it houses the heart
00:02:04
it houses the trachea and the other
00:02:07
different types of structures right so
00:02:08
again this is going to be located within
00:02:10
the medyum and it overlies the heart now
00:02:13
the thymus gland is what's called a
00:02:15
primary lymphoid organ so it's a primary
00:02:21
lymphoid organ what does that mean so
00:02:24
this is the one that's actually going to
00:02:25
allow for tea cells to develop
00:02:27
completely the other primary lymph oid
00:02:30
organ is the red bone marrow that's
00:02:31
where the B cells develop right okay so
00:02:35
this primary lymphoid organ it's
00:02:37
primarily going to be functioning during
00:02:40
the younger ages of life so during the
00:02:43
infancy and during the childhood and up
00:02:45
to early early adolescence right but
00:02:47
once we hit to the early early ages of
00:02:49
adolescence the thymus gland activities
00:02:51
begins to decline and then it starts to
00:02:54
atrophy and then it just becomes filled
00:02:56
with fibrous tissue and becomes pretty
00:02:58
much non-functional so again remember
00:03:00
that that the thymus gland is
00:03:01
specifically functional at Young ages
00:03:03
like during infancy and childhood and
00:03:05
early early adolescence but as you start
00:03:07
to get older it atrophies means it
00:03:09
getting smaller and then on top of that
00:03:11
it gets filled with fibrous tissue and
00:03:13
actually becomes nonfunctional so let's
00:03:15
see what does the thymus gland do that
00:03:17
kind of draws these te- cells over to
00:03:20
him so that they can undergo specific
00:03:21
types of selection and
00:03:23
maturation it secretes specific types of
00:03:27
chemo kindes right so these chemotactic
00:03:29
agents what are these chemotactic agents
00:03:32
that it's secreting that are drawing
00:03:34
these te- cells into this
00:03:37
area these chemotactic agents there's a
00:03:39
couple of them one is actually going to
00:03:41
be called
00:03:44
thymosin another one can be called
00:03:46
thyoxin
00:03:50
another one can be called thop
00:03:54
potin and then there's other ones that
00:03:56
because thop you actually you know
00:03:58
specifically uh actually we put thop
00:04:00
because thop potin no yeah we can put
00:04:02
thop I'm sorry I'm think I was thinking
00:04:04
about throp but thop potin specifically
00:04:07
he also helps to be able to draw these
00:04:08
t- cells to the thymus clam another one
00:04:11
that's really really important is just
00:04:13
generalize thymic
00:04:16
factors okay so what are these chemicals
00:04:19
right here these chemicals are acting to
00:04:21
be able to draw this t-
00:04:25
cell towards the thymus gland so they're
00:04:27
initiating what's called this chemo
00:04:30
taxis if you will right so this chemotax
00:04:33
is trying to draw this T Cell precursor
00:04:35
into the thymus gland so now this T cell
00:04:38
is actually going to start tracking its
00:04:39
way to the thymus Clan so now that it's
00:04:41
got received the stimulus from these
00:04:43
certain chemicals it's now going to
00:04:45
start moving its way where towards the
00:04:50
thymus Clan where it's going to undergo
00:04:52
specific maturation processes okay so
00:04:55
now now that we know exactly what's
00:04:57
happening with this T cell and how it's
00:04:59
getting to the thus gland to mature now
00:05:00
we can go ahead and zoom in and see
00:05:02
exactly what's happening at the
00:05:04
molecular and cellular level
00:05:08
okay
00:05:11
okay so if you look here guys we have
00:05:13
our thymus gland and we're just really
00:05:15
really zoomed in on it now okay so we
00:05:17
have our thymus gland here which again
00:05:19
is a primary lymphoid organ and then if
00:05:22
you look over here I just basically have
00:05:24
the spleen okay which is a secondary
00:05:26
lymphoid organ and a lymph node which is
00:05:28
another secondary FOID organ let's go
00:05:31
ahead and start right here and work our
00:05:33
way towards the left going with each
00:05:35
type of event all right so we have our T
00:05:37
Cell right here right now this te-
00:05:40
cell it has its DNA and it's basically
00:05:45
it's a te- cell it hasn't undergone any
00:05:47
different no mechanisms have been acted
00:05:48
on upon it yet right so it has it
00:05:50
doesn't really have any different types
00:05:52
of receptors on it and I'll explain what
00:05:54
those receptors are those proteins but
00:05:57
what happens is if you remember those
00:05:59
chemicals that the thymic cells were
00:06:00
secreting so here's our thymic cell this
00:06:02
is a thymic cell or an epithelial cell
00:06:06
within the thymus right it's secreting
00:06:08
those chemicals if you remember them
00:06:09
again
00:06:11
thymosin thop
00:06:15
potin thymic
00:06:17
factors so many many different types of
00:06:20
chemicals what is that doing that's
00:06:22
acting on this T Cell so when it acts on
00:06:25
this te- cell it stimulates the te-
00:06:27
cell's genes a specific cell of genes
00:06:30
though and these genes produce a very
00:06:33
very very important product and these
00:06:35
enzymes that they're actually produced
00:06:37
are called rag one
00:06:41
and rag two why did I mention these all
00:06:46
right here's why when these genes get
00:06:48
activated and they produce these
00:06:50
proteins called recombinases so rag one
00:06:53
and rag 2 what recombinases do is they
00:06:56
basic basically Shuffle the DNA so when
00:06:58
they Shuffle that d they produce
00:07:00
different types of proteins for
00:07:02
different types of antigens so what is
00:07:04
it going to produce on its actual
00:07:06
surface so these rag ones and rag twos
00:07:08
are going to act on specific genes
00:07:10
Shuffle the DNA and lead to the
00:07:12
production of a specific protein which
00:07:14
is called a
00:07:16
TCR so this is called a
00:07:19
TCR which stands for T Cell receptor now
00:07:23
why did I mention this rag one or rag
00:07:25
two what's the specificity of it if I
00:07:27
have an antigen here some type of
00:07:28
foreign antigen and it's circular if I
00:07:31
have some type of antigen and it's a
00:07:32
square antigen or a triangular antigen
00:07:35
and this is foreign this TCR that we're
00:07:38
making has to be able to recognize any
00:07:40
of these foreign antigens so the
00:07:42
recombinases might activate and Shuffle
00:07:44
the genes to produce a TCR that fits
00:07:46
this circular antigen then it might make
00:07:49
a TCR to fit this Square antigen and
00:07:53
then it might make a TCR to fit this
00:07:56
triangular antigen right but all of
00:07:58
these TC RS are different from one
00:08:00
another and unique and that's because of
00:08:02
these recombination enzymes all right
00:08:04
that's enough about
00:08:05
that these chemicals are also activating
00:08:08
other genes and these genes are they're
00:08:11
uh let's say that we have another line
00:08:13
coming down here activating another set
00:08:15
of genes and these genes are producing
00:08:17
what's called CD proteins or cluster
00:08:20
differentiation proteins so let's draw
00:08:22
one here in Black let's say this protein
00:08:25
right here is actually going to be let's
00:08:27
say this is cd8
00:08:29
so cluster differentiation eight and
00:08:32
let's say that this uh red protein right
00:08:34
here that we're going to draw is going
00:08:36
to be another cluster differentiation
00:08:38
protein but this one's called
00:08:41
CD4 so what's happened here in this
00:08:44
first step here this is where most of
00:08:45
the stuff is actually occurring this
00:08:47
these chemicals thymos and thop thymic
00:08:50
factors are stimulating this T Cell
00:08:51
precursor to make tcrs but different
00:08:54
types because of the rag one and rag two
00:08:56
cd8 molecules and CD4 molecules
00:09:00
now this t- cell comes over
00:09:02
here look at it it's such a beautiful
00:09:05
thing right this whole process it's
00:09:06
unbelievable how all these things happen
00:09:08
but again what will this guy have on his
00:09:09
membrane he'll have a
00:09:11
CD 8 he'll have a CD4 and I'll mention
00:09:16
why these proteins are really
00:09:18
significant so it has a
00:09:21
CD4 and then it also has
00:09:24
a
00:09:26
TCR looks like a bunny all right so now
00:09:30
this thyx cell is going to present some
00:09:32
specific types of molecules on its cell
00:09:35
membrane so let's say one of them it
00:09:37
presents specifically binds with cd8 all
00:09:41
right so this molecule specifically
00:09:43
binds and only with CD and this molecule
00:09:46
is called
00:09:49
mhc1 okay and CDA binds with them
00:09:52
perfectly it's a good binding it's not
00:09:55
too not too strong but it's just the
00:09:57
right type of binding right then CD4 it
00:10:01
comes and it perfectly bonds with
00:10:05
CD4 and this molecule is called
00:10:11
mhc2 and these MHC stands for major
00:10:14
hysto compatibility complex type one and
00:10:17
type two these two molecules have
00:10:19
recognized and interacted with these MHC
00:10:23
molecules if they do interact with these
00:10:25
MHC molecules that's a good thing
00:10:27
they've positively selected did this so
00:10:30
this right here this event where they
00:10:31
recognize them is called positive
00:10:35
selection because they recognized these
00:10:39
t- cells recognized the thymic cells
00:10:42
mhc1 and mhc2 molecules appropriately
00:10:46
okay if it doesn't recognize this what's
00:10:49
going to happen this cell will undergo
00:10:52
apoptosis because we need these cells to
00:10:54
be able to recognize these mhc1 and mhc2
00:10:57
so again if this TC it cd8s and it cd4s
00:11:01
don't bind with the mhc1 and mhc2 then
00:11:04
it'll undergo apoptosis so again if this
00:11:07
guy does not if this t- cell if it cd4s
00:11:10
and cd8s don't recognize these MHC
00:11:12
molecules appropriately and respectively
00:11:14
what's going to happen it's going to
00:11:15
undergo apoptosis how does that happen
00:11:18
well these thymic cells we're not really
00:11:19
concerned with the whole mechanism but
00:11:21
just know that it secretes these
00:11:23
specific
00:11:25
chemicals I'll just mention it anyway
00:11:26
it's called f and f basically works
00:11:31
on this specific receptor here on the
00:11:34
actual t- cell and triggers the genes to
00:11:36
undergo what activate specific genes to
00:11:39
produce apoptosis okay but that's if it
00:11:41
does not recognize class one and class
00:11:43
two all right but he survives let's say
00:11:46
this guy survives like hooray okay we go
00:11:48
to the next
00:11:49
step so what's the next
00:11:51
step okay now it's this guy's turn now I
00:11:56
didn't show show it specifically here
00:11:58
but I'm going to show it now so let's
00:11:59
say here I draw mhc1 molecule right so
00:12:05
here's this
00:12:06
MHC one molecule same thing from over
00:12:10
there this blue molecule right here that
00:12:11
I'm going to draw is still the same
00:12:13
thing it's the
00:12:15
MHC 2 molecule right now these guys are
00:12:21
going to have always like a self peptide
00:12:23
that's a part of these MHC molecules and
00:12:26
usually they put it like right here
00:12:28
right so let's say goes specifically
00:12:31
right there
00:12:32
now this t- cell if you remember what
00:12:35
did it have I'm going to draw the CD
00:12:36
protein a little bit different now so
00:12:38
this red one is going to be
00:12:41
CD4 and again this black one is going to
00:12:44
be
00:12:46
cd8 which are interacting appropriately
00:12:48
with the class one and the class two but
00:12:50
if you remember what other structure do
00:12:51
we have we had that
00:12:53
TCR now the
00:12:56
tcrs of this t- cell if
00:12:59
it recognizes these self antigens or
00:13:02
these self peptides that is not a good
00:13:05
thing that means that in the future
00:13:06
these tea cells could go and interact
00:13:08
with our own tissues and then if it does
00:13:10
interact with our own tissues and it
00:13:12
causes damage to our tissues that can
00:13:13
lead to autoimmune disorders so we don't
00:13:16
want that so in other words I don't want
00:13:18
these tcrs to recognize my own self-
00:13:21
peptides or self antigens I only want it
00:13:23
to recognize foreign things so what does
00:13:25
it do so again so for example that one
00:13:27
was circular let's say that this
00:13:29
structure right here is like jaggedy so
00:13:32
it's not interacting perfectly right so
00:13:34
that's a good thing and again let's say
00:13:36
that this one was circular right here
00:13:37
and this one was
00:13:40
jaggedy and that TCR doesn't fit this
00:13:43
self antigen it doesn't interact with it
00:13:45
and if it doesn't interact with it
00:13:47
that's a good thing that's called
00:13:49
negative
00:13:54
selection okay but if this TCR fits
00:13:58
perfectly in binds to that self peptide
00:14:00
that's not a good thing and that cell
00:14:03
will
00:14:03
undergo
00:14:05
apoptosis right so again why will it
00:14:07
undergo apoptosis if this te- cell has
00:14:10
its TCR recognized these self peptides
00:14:13
and again how will it cause apoptosis
00:14:15
it'll secrete the chemical called f and
00:14:18
f will bind onto a specific receptor and
00:14:21
Trigger this Pathway to lead to
00:14:24
apoptosis so it's finished such a great
00:14:27
thing here we've gone through how many
00:14:28
steps so Far We've gone through the
00:14:30
first step we've gone through the Second
00:14:31
Step it's got one more thing that has to
00:14:33
do before it can finally be a functional
00:14:35
t- cell so it's done all of this test
00:14:39
perfectly it comes to this last Point
00:14:41
here and at this last Point here we're
00:14:44
going to draw these molecules again
00:14:45
let's say I have this th let's actually
00:14:46
say I have two thymic cells one here one
00:14:49
down here and this t- cell has a choice
00:14:53
it's got his choice but really it's
00:14:55
random so let's say down here I draw an
00:14:58
MHC C1
00:15:00
molecule okay so that's my MHC one
00:15:03
molecule and let's say up here I draw
00:15:06
specifically
00:15:07
a mhc2
00:15:11
molecule if you remember what's this
00:15:13
cell right now this cell that we had he
00:15:16
is TCR positive CD4 positive and cd8
00:15:22
positive so he has all of these
00:15:24
different things that he needs to
00:15:26
interact he comes over here
00:15:29
and let's say just by perfectly random
00:15:32
chance I know it seems crazy but just by
00:15:34
perfectly random chance the CD4 molecule
00:15:38
on this t- cell interacts with the mhc2
00:15:41
so just perfectly this CD4 molecule here
00:15:44
interacts perfectly with the mhc2
00:15:47
molecule but it doesn't it CDA doesn't
00:15:50
interact with the class one this T cell
00:15:53
is going to specifically what's going to
00:15:55
happen
00:15:56
is if it interacts with the class two
00:15:59
the genes will
00:16:03
downregulate the cd8 molecule so if you
00:16:06
remember here was the cd8 but let's say
00:16:07
that this interaction doesn't happen and
00:16:10
that this T Cell only has a CD4 interact
00:16:12
with mhc2 if that reaction only happens
00:16:15
you'll upregulate these CD4 molecules
00:16:18
and you'll down regulate these cd8
00:16:19
molecules what does downregulate mean
00:16:21
you'll decrease the number of cd8s what
00:16:22
does U regulate me you'll increase the
00:16:24
number of
00:16:24
cd4s so what would this cell look like
00:16:27
for example and I'm not going to draw
00:16:28
all the CD4 for is perfectly I'm just
00:16:29
going to draw red markers on this I'm
00:16:32
just going to draw little red dots here
00:16:33
there's a whole bunch of red dots there
00:16:36
representing the cd4s and we might have
00:16:39
at this point in time maybe one cd8
00:16:41
right that's it this is this cell right
00:16:44
here if it has all of these nice little
00:16:47
beautiful cd4s and again what else would
00:16:49
it have here I'm just going to draw
00:16:50
these in purple these tcrs these T cell
00:16:54
receptors and it down regulates all
00:16:56
these cd8s and up regulates all these
00:16:58
cd4s
00:16:59
this cell is specifically a
00:17:03
t helper
00:17:05
cell
00:17:07
okay now let's say that this let's say
00:17:11
another T Cell comes through so another
00:17:13
t- cell comes through and it's by random
00:17:16
chance I know it seems crazy but by
00:17:18
random chance this cd8 molecule
00:17:21
perfectly interacts with the mhc1
00:17:23
molecule and this interaction between
00:17:25
the CD4 and the mhc2 interaction doesn't
00:17:28
occur
00:17:29
this
00:17:31
cell
00:17:32
will
00:17:34
downregulate his CD4 molecule so in
00:17:37
other words he'll decrease the amount of
00:17:38
cd4s and he'll upregulate his cd8s
00:17:42
because he interacted with the class one
00:17:44
so now let's draw this molecule
00:17:46
here so again what we have all out of on
00:17:48
the surface these cd8 molecules
00:17:52
there and again he'll start down
00:17:54
regulating he shouldn't have I'm just
00:17:57
showing it for an example this T helper
00:17:59
cell shouldn't have any cd8 molecules
00:18:00
I'm just giving you the idea that it
00:18:02
should downregulate the cd8s for this t-
00:18:05
helper same thing with this guy he
00:18:06
shouldn't have any CD4 molecules I'm
00:18:08
showing it to you as an example that
00:18:10
these CD4 molecules will be
00:18:12
downregulated and completely diminished
00:18:14
right but again it'll have a lot of
00:18:16
these
00:18:17
cd8s and it'll also have a lot
00:18:20
of tcrs right so this is our TCR T Cell
00:18:23
receptor this cell specifically called a
00:18:27
t
00:18:30
cyto toxic
00:18:33
cell
00:18:35
okay one last one but it's the easiest
00:18:38
one some of these cells it's it's really
00:18:40
weird these cells some of these t-
00:18:42
helper cells can become T regulatory
00:18:45
cells and some of these cytotoxic te-
00:18:48
cells can become t-regulatory cells so
00:18:51
I'm going to draw this right up here
00:18:52
then and on what I'm saying here again
00:18:55
is that some of these cells some of the
00:18:56
CD4 cells and some of the the actual CDH
00:19:00
cells can literally become so let's say
00:19:03
I have two of them over
00:19:06
here they can become T regulatory cells
00:19:09
in these T regulatory cells again what
00:19:10
can they have on their membrane they
00:19:12
could have CD4
00:19:17
molecules and what else would they have
00:19:19
tcrs you have to have the tcrs these
00:19:21
purple molecules right
00:19:23
here but this other cell he would have
00:19:29
cd8
00:19:30
molecules and these cd8
00:19:34
molecules as well as TCR molecules now I
00:19:38
know this seems weird because I just
00:19:39
said this was a t- helper cell and this
00:19:42
was a t-cytotoxic cell through certain
00:19:44
types of cyto kindes these actual T
00:19:47
helper cells and T cytotoxic te- cells
00:19:50
can differentiate into a specific type
00:19:51
of cell and this is called a t
00:19:55
regulatory um sometimes they call them
00:19:57
suppressor also Al cells and these are
00:20:01
very very important for being able to
00:20:02
regulate um prevent these uh regulate
00:20:05
the activity the te Helper and the tea
00:20:06
cytotoxic to prevent autoimmune diseases
00:20:10
little piece of it there is a specific
00:20:13
mechanism of how these guys can go into
00:20:14
forming te regulatory I'm not going to
00:20:16
hit too much into it but they say it's
00:20:18
due to certain types of proteins that's
00:20:20
present on this guy like maybe the
00:20:23
cd25 and certain chemicals like
00:20:26
interlukin um 2 that can regulate this
00:20:29
activity but nonetheless just know t-
00:20:32
helper cells and T cytotoxic te- cells
00:20:34
some of these guys can get converted
00:20:36
into T regulatory okay so we formed all
00:20:38
our three cells all of our three T cells
00:20:40
that we need now what happens now these
00:20:43
guys go and get specifically put into
00:20:46
different lymphoid organs what is some
00:20:47
of them let's just say I draw with one
00:20:49
cell here one cell it could be any of
00:20:52
these these guys coming right in here so
00:20:55
what are these little black cells right
00:20:57
here these little black cells are called
00:20:58
te- cells and they can go to the lymph
00:21:01
node and they can park themselves right
00:21:03
there in the Deep part of the cortex of
00:21:05
the lymph node where else could they go
00:21:07
they could come in here into the spleen
00:21:09
and in the spleen what's important is
00:21:12
that these te- cells literally form
00:21:14
right around these red blood vessels
00:21:17
that we have drawn right here these
00:21:19
capillaries called sinusoidal
00:21:21
capillaries they come and Surround these
00:21:23
blood vessels and form what's called
00:21:25
periarteriolar lymphatic sheaths and or
00:21:28
specifically they just call it white
00:21:30
pulp they make What's called the white
00:21:34
pulp so again what can happen these te-
00:21:37
cells can go to the lymph nodes and park
00:21:40
into the deep part of the cortex or they
00:21:41
can surround these uh specific cido
00:21:44
capillaries and form what's called White
00:21:46
pulp or periarteriolar lymphatic sheaths
00:21:49
and another place you see these
00:21:50
t-regulatory cells there's a specific
00:21:52
place for them they literally come into
00:21:55
this specific area into the thymus gland
00:21:58
where they're primarily going to be this
00:22:01
where a good concentration of them could
00:22:02
be but they can be again they could be
00:22:04
all over the place too they could be in
00:22:05
the uh the spleen as well as the lymph
00:22:07
noid lymph node but they've been found
00:22:09
to be concentrated in the thymus gland
00:22:11
in a specific area which is called the
00:22:15
hassal cor pusles or the uh thic cor
00:22:19
pusles okay so again in brief it would
00:22:24
undergo this T Cell will undergo
00:22:26
positive selection it'll undergo
00:22:27
negative selection positive meaning it
00:22:29
recognize mhc1 and mhc2 negative
00:22:32
selection meaning it does not recognize
00:22:33
the self peptide or the self antigen
00:22:36
then after that by random chance it'll
00:22:38
either get if it CD4 interacts with mhc2
00:22:40
it'll form a CD4 cell or a t- helper if
00:22:43
by random chance the cd8 interacts with
00:22:45
the mhc1 it'll actually turn into a
00:22:47
t-cytotoxic and then some of these t-
00:22:50
helper cells and t-cytotoxic te- cells
00:22:52
can be converted into T regulatory cells
00:22:55
maybe through a cd25 interlukin 2
00:22:57
interaction
00:22:59
right and then these cells all of these
00:23:01
cells can be sent to secondary lymphoid
00:23:04
organs like the core deep part of the
00:23:06
cortex in the lymph node or the white
00:23:08
pulp within the spleen or the hassal Cor
00:23:11
pusles in the thymus and there's other
00:23:12
different areas too besides that they
00:23:14
can go to the tonsils they can go into
00:23:16
the um the mucosa Associated lymphatic
00:23:19
tissue which could be in your
00:23:20
respiratory tract your urogenital tract
00:23:23
they can be all over the place right but
00:23:25
again know that this is the entire
00:23:27
process starting from where where do we
00:23:30
start and an overall Outlook starting in
00:23:33
the red bone marrow that's where they're
00:23:35
made they're made within the red bone
00:23:36
marrow but they mature in the thymus and
00:23:40
then from there where can they go they
00:23:42
can go to secondary lymphoid organs
00:23:43
where they'll carry out their functional
00:23:45
processes all right Engineers I hope
00:23:47
that helped take it easy
