MARIAN DIAMOND: All right,
appropriately, we're
discussing the digestive system.
And I trust you all digested
well over the holidays
and enjoy this.
So let's continue with
the second largest
gland, the pancreas.
What was the first
largest gland?
Waiting for you.
I'm waiting for him.
Thank you.
All right, thank you.
All right, the second
largest gland--
this gland, then, has two main
types of cells, the exocrine
and endocrine.
And the exocrine
cells are called
acinar cells, acinar cells.
And they secrete enzymes,
which go into ducts,
secrete enzymes into ducts.
And the ducts eventually
converge into a duct
which joins the bile duct.
And this duct, then, liberates
the contents into the duodenum.
Two pancreatic enzymes would
be examples, chymotrypsinogen
and trypsinogen. Then
the endocrine cells
are called the
Islets of Langerhon.
And these islets, then, are
scattered in little groups
amongst the acinar cells.
By far, the greatest number
of cells are acinar cells.
There are more islets in
the tail of the pancreas
than in other parts
of the pancreas.
We may have mentioned previously
the location of the pancreas.
So you can see where
the tail is if we
have the stomach coming in.
There's an awful lot of noise.
Do you know what's causing that?
No.
This is our stomach.
This is our pyloric sphincter.
And we'll find that
the pancreas, then--
going to switch with me?
STUDENT: Yeah
MARIAN DIAMOND: Thank you.
STUDENT: Let's check, 1,
2, 3, 4, check, 1, 2, 3, 4.
MARIAN DIAMOND: All right,
we'll see how that is.
I hope it's a little
quieter for you.
Thank you very much.
So we want to put, then, the
pancreas in between the stomach
and the duodenum here.
Give it a little more of a tail.
So in yellow, we
have our pancreas,
which will then have a head,
a neck, a body and a tail--
so head, neck, body and tail.
And we said, most of the islet
cells are down in the tail.
So the islet cells are
of different types.
We have alpha cells, beta
cells and delta cells.
And each secretes a
different hormone.
The alpha cells create what?
Glucagon.
And that will raise blood sugar.
The beta cells, insulin,
which will lower blood sugar.
And the delta
cells, somatostatin,
somatostatin, which will inhibit
other pancreatic hormones.
Anybody know anyone who's
had pancreatic cancer?
How are they doing?
They died, yes.
Used to be, within
a year after you
hear from pancreatic
cancer, that they died.
But I've been told now,
they're having greater success
to carry them through.
So if you have
somebody, tell them
that there are some
positive outlooks.
But it used-- we
just all dreaded
getting pancreatic cancer.
All right, with that small
introduction to the pancreas,
let's move on to the kidney.
Let's just call it the
urinary system to start with.
That's better.
So our urinary system
is designed, then,
to form urine and excrete urine.
So we made several
structures involved here.
We're going to have two kidneys.
And they will be involved
in forming urine.
And we'll have to your
ureters that will excrete--
let's put just pass urine.
We'll have one urinary bladder.
So now after taking
anatomy, you know
when you say bladder, classify
whether it's urinary or gall.
And this will store--
some people say and
concentrate-- urine--
some books, not in others.
And then one urethra--
and the urethra, then,
will convey the urine
to the exterior.
So let's take our
kidneys first, then,
and see how they form urine.
First, what's the
size of a kidney?
Between 4 and 5 inches
long, 2 to 3 inches wide
and 1 inch thick.
These will vary.
Did I tell you, when we
were teaching in Venezuela,
they thought we were urologists
and not neurologists.
And they took us into a
room filled with urologists.
And I looked at my husband.
And he looked at me.
What are we going to do?
And I said, well, I'll
ask him a simple question.
What's the difference between
the right and left kidney?
Guess what we discussed?
They never thought of it.
Does it make a difference
when you transplant?
They had never thought of it.
A kidney was a kidney.
We gave him lots to think about.
We were completely
ignorant other than what
I know with my basic anatomy.
Anyhow, so it shows you what--
you've got a lot of adrenaline.
You can bring
things out rapidly.
And I could tell you lots of
stories that way , but I won't.
We'll continue on why
we learn about kidneys.
Then we want the
location of the kidney.
It's going to be on our
posterior abdominal wall,
posterior abdominal wall.
And it will be posterior to the
parietal peritoneum, posterior
to parietal peritoneum, which
lines the abdominal wall.
But it's posterior to
parietal peritoneum.
So it's called retro
peritoneal, retro peritoneal.
Important to know
what structures
are retro peritoneal.
So if they are producing
something abnormal,
it won't go to the
peritoneal cavity.
It's retro peritoneal.
Now how do we define where it
is on this posterior abdominal
wall?
It'll make a
difference whether it's
the left or the right kidney.
This is the left kidney.
It's going to be
between T12, L1, L2, L3.
So we'll have the upper pole up
here at T12 and the lower pole
down at L3.
Now do you think
the right kidney is
going to be higher or lower?
And defend your answer.
No idea.
It's going to be lower,
because we have the right lobe
of the liver over here.
So it has to be lower
to be below the liver.
We don't have the big
lobe on the left side.
So the right kidney
is lower than left,
because of large right
lobe of the liver.
So that's location and size.
Now let's begin to
look at structure.
First, we'll look at
external structure.
When you define the shape
of a kidney to somebody,
you say it's bean-shaped.
When you define a
bean to somebody,
you say it's kidney-shaped.
But we know what
you're talking about.
So it's being bean-shaped.
The indentation
is called a hilus.
And in the hilus, we'll have
the renal artery coming in.
Where's the renal
artery coming from?
Thank you, perfect.
We learn that again,
the importance
of knowing that
relationship when we learned
about the abdominal
aorta in [INAUDIBLE]
lecture on the vascular surgery.
Then we have the renal
vein entering at the hilus.
And-- I'll have to
sort of overlay it,
or maybe what I'll do
is make another one--
we'll have the renal pelvis.
What's pelvis mean?
Basin.
Here we have the renal
pelvis coming out.
And it will continue
into the ureter.
So that gives us
some basic landmarks.
One more-- no,
let's go internal.
This is just internal.
We'll have the cortex
and the medulla.
What does cortex mean?
Bart, good for you.
That was quick.
Now we're going to look at the
internal tubular structure.
We're going to-- kidney
is just masses of tubules.
We have those
which are secretory
and those which are excretory.
These secretory
will consist of--
I want to be sure I give
you the special name,
but I don't mix it up here.
Secretory will be the nephron.
And the nephron is the
structural and functional unit
of the kidney.
What's the structural and
functional unit of the liver?
[INAUDIBLE],, how
about compact bone.
We've learned them that way.
And muscle?
All right.
So now what's the
nephron consist of?
We have the secretory component.
And it will have the
Bowman's capsule.
I hope you corrected.
One of the students saw it
was misspelled up there.
I didn't write clearly
when I turned that in today
to be typed, so I apologize.
So it should have been Bowman's
capsule, Bowman's capsule
and glomerulus.
And this is called
the renal corpuscle.
And we then have
the renal tubules.
And these will be the
proximal convoluted tubule,
proximal convoluted
tubule, the loop of Henle--
have you ever known a Mr. Henle?
They do have rare
names, don't they--
distal convoluted tubule.
And these are our renal tubules.
And these, then, all make
up our nephron, our unit.
So we'll start, put some
functional significance
into this group of tubules.
Have you ever thought about how
many structures in your body
are tubules, how
many of our systems?
We had the respiratory.
We had the digestive.
We had the nervous.
Now we're getting our
urinary, all tubules.
So we're going to start
with our Bowman's capsule.
It's going to have two layers.
Now we want to
leave lots of room,
because we've got to go down.
We've got to go wide.
And we've got to go up.
So we're going to put the
capsule right in about here.
We have an outer layer.
What are you going to
call the outer layer?
Ooh, that should be so fast.
Parietal, right, parietal?
Parietal layer of Bowman's
capsule will be one.
And it will consist of
simple squamous epithelium.
And an inner layer--
what are you going to
call the inner layer?
Visceral, right, the visceral
layer of Bowman's capsule.
I'm just not going
to write it out.
That's the visceral layer.
And the visceral
layer consists of what
are called podocytes,
podocytes, foot cells.
And these are to
allow for filtration.
It's hard to draw them, but you
get that sort of general idea
that you have a cell with
little foot processes.
And these foot processes sit
on the basement membrane,
so that filtration can
come through these openings
between the foot
processes for filtrate.
So with this, I want to
introduce the term glomerulus,
which is the other component
of the nephron in this region.
The glomerulus now,
we're not going
to go through all the
arteries which lead to it.
But our purpose in forming
a nephron, as we said,
was to filter plasma, make
a glomerular filtrate,
which will eventually
form urine.
So we have to have
the structures that
will carry these functions out.
So we've got to bring
the blood supply
into our Bowman's capsule.
It'll be coming in as
an afferent arteriole.
I'll leave room here,
because we've got
to bring other things above it.
This will be-- we'll call
it 3 here, move it over.
3 equals an afferent arteriole
bringing in arterial blood.
It's going to break up
into a massive capillary
bed that comes right
against our podocytes
and our visceral layer.
And this will be 4.
4 Will be the glomerulus.
So that's the capillary
bed, which will
be bringing in arterial blood.
And then after the
filtrate has been formed,
the blood continues on as the
efferent arterial, E for exit.
5 is our efferent arteriole.
So now our purpose is to
form a filtrate that's
going to start collecting
in this series of ducts
that we want to develop.
So for blood to form
a glomerular filtrate,
the plasma will go through.
We go from the
capillary endothelium
then through the podocyte, then
through the basement membrane.
And then we will have
glomerular filtrate.
What do you think's the most
important structure here
to be getting our
glomerular filtrate?
Basement membrane.
The basement membrane will not
allow molecules over 70,000
with the molecular weight.
Molecules with molecular
weight over 70,000
can not pass the
basement membrane.
How would you like the job
in the lab of isolating
the basement membrane?
They were doing this in
Copenhagen back in the '60s--
tremendous progress since then.
All right, now we
formed our filtrate.
We want to continue
on with our picture
to see what happens
to get us some urine.
But in order to do
this, let's find out
how much blood goes through
the kidneys each minute.
Well, it's said, 1,200 CCs of
blood, out of that, 125 CCs
of glomerular filtrate--
and out of that, 124 CCs
of glomerular filtrate
are reabsorbed.
So how much urine do we get?
1 cc.
You think you could design
a kidney more efficient?
What have we got?
1,200 CCs of blood is needed
to extract 1 cc of urine.
This is 125 CCs of
filtrate per minute.
Picture your kidneys.
Do you see them there?
Never think about them, just
get mad if they don't work
or if they work too
efficiently after a beer party.
And here we are, 124 reabsorbed.
I guess that that's
the end product.
Isn't that amazing?
Now we've got this for later.
But I think that's
pretty dramatic
to have a gland functioning
in one minute for that kind
of processing in your body.
And you never, ever
thought of it before.
All right, now
we've got to follow
to see what's happening where
this glomerular filtrate is
coming down now.
See, we've made our filtrate.
It's got to go through
our tubular system.
So we first encounter--
we going to draw it and
then come back and speak
about it, all right?
We're going into the
proximal convoluted tubule.
And we're just but make
one convolution here,
even though there are hundreds,
as a representative sample.
This will be my proximal
convoluted tubule.
This will be our loop of Henle.
That's the descending limb.
And now we'll go back up
with the ascending limb.
And it will come all the way up.
Now this is why I asked
you to keep space up here.
That was our afferent arteriole.
I'm going to take it
off at the moment.
And take it all the way up,
all the way up, clear around.
I'm going to switch
these, because I
want this come around and out.
This one should be on the
inner coming in like this.
There we go.
So that makes our distal
convoluted tubule.
That gets us
through our nephron.
So now, what's happening?
What do we need these?
And what are the differences
between or amongst them?
So let's take our proximal
convoluted tubule.
Most of your cortex consists
of proximal convoluted tubule.
So it will be lined
with cuboidal cells
with a brush border.
It just look like
a brush when early
with the light microscope.
With the electron
microscope, they
learned that the brush border
is actually microvilli.
So as we had in the intestine,
increasing surface area
by having microvilli.
I'll show pictures of these.
They're very distinct.
Now what's the function here
of my posterior convoluted--
did I say post?
Proximal, it should be,
proximal convoluted tubule.
Number one, it's going to
absorb 100 CCs of water.
It's going to absorb any
glucose that comes in.
It will absorb amino acids.
You don't want protein
in your urine--
amino acids.
It will absorb sodium
ion and vitamin C.
A tremendous re-absorption
going on in all
of those proximal
convoluted tubules.
How about the loop of Henle?
That descending limb will
be reabsorbing water.
The ascending limb will reabsorb
sodium ion and chloride.
Now what's left for the
distal convoluted tubule?
We'll have water.
We'll have calcium ion.
We'll have phosphate and sodium.
But something
different is happening
in the distal convoluted tubule
rather than just absorption.
We'll have secretion.
This absorption
with all of these.
And then there'll be secretion.
What's being secreted?
Hydrogen ion and potassium ion,
hydrogen ion and potassium.
So tremendous ion exchange
going on within your kidneys.
But now say that you
have low blood pressure
and you have low sodium.
Did he put-- yes, OK, well,
then I'll give this next time.
Because I want you to
see the slides while
it's fresh with this.
First slide, please.
Thank you.
This is just to show the
position of the pancreas
here with the head would be
over further-- a little bit
distorted.
You'll learn all about the
omentum and all these membranes
when you take advanced anatomy.
But the head would be here,
and the body here, and the tail
here, neck in between.
In the next one.
Now this is a very special
stain, Mallory azan.
And it shows these
are acinar cells.
With this particular
stain, you can truly
pick up the islets of
Langerhans in the pancreas.
But this is a rare stain.
What you'll usually get in
pathology is the next one.
Next slide.
Now where do you see?
Here are islets here.
These are acinar stains.
This is with an iron hematoxylin
and aniline blue stain,
entirely different, but
showing what staining can
do to demonstrate structure.
In the next one.
And now we're in the
cortex of the kidney.
It has a connective
tissue membrane,
a good, thick, protective one.
Here is our glomerulus
in the Bowman's capsule.
This would be the
parietal layer.
The visceral layer is
adherent to the capillaries
in the form of podocytes.
Now most of these are
proximal convoluted tubules.
In the next one.
Now this is showing the
blood supply coming in,
the interlobar arteries.
There are arcuate arteries.
Then an interlobular
artery comes on up
and gives off the glomeruli via
the afferent arteriole, which
you can see, this
is the glomerulus.
In the next one.
And this is with an
India ink injection
into the vascular supply.
So you can see the
main trunks coming up,
the interlobular ones and
then the afferent coming in.
Not all of them will have both,
because this is a big ball
and just we get a section
which will show both.
In next-- next, please.
Now this is the Bowman's
capsule to show you
it truly is just a
simple squamous capsule.
This is the area between
the parietal layer
and the visceral layer, which is
adherent to the capillaries bed
here.
And you're going
to be collecting
the filtrate in here.
In the next one.
And this shows this is
just a normal iron--
let's see.
This is hematoxylin eosin stain.
You have the parietal layer then
the visceral layer adherent,
again, to the endothelium.
In the next one.
Now we have here an afferent
arteriole coming in.
This is a rare one.
And the efferent is--
no, it's going to be
coming out over here.
No, what is this?
That's the beginning
of the tubular system.
So it's difficult to
determine which is afferent
and which is efferent here.
But on the slide,
it says it shows
both afferent and efferent.
So it has to be one of these.
And this would be your
tubular system collecting
the glomerular filtrate.
That's a rare slide.
I've never seen one
like this before.
In the next one.
And this now shows
cross-sections
of your proximal
convoluted tubule.
You see the blue?
That's your brush border.
That's the way it looks
with the light micrograph.
But it's, in reality,
microvilli for absorption.
100 CCs has to come
back in of water
in this proximal
convoluted tubule.
In the next one.
And here's another different
stain to show how--
but you can see why
early anatomists called
it a brush border.
And the next one.
And now, what's this?
Hm, pardon?
Everybody should know that.
What is it?
I'll wait until you say.
Where does the filtrate
go as it leaves
the proximal convoluted tubule?
Into the loop of Henle.
See, isn't that
a beautiful loop?
Have you ever seen a slide
like that actually catches it
amongst all these tubules?
So that's the loop of Henle.
The layer going down is thinner
than the layer coming back up.
In the next one.
And this is now going to be
one of the collecting ducts.
Because after the urine
leaves the nephron,
it enters collecting ducts.
In the next one.
And these are collecting
ducts in cross-section.
So you see this would be
loops of Henle down here
in cross-section.
But the big ones are
now collecting ducts.
In the next one.
That's it.
All right, enjoy your afternoon.
