Cancerous colon tissue

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Kind: captions
Language: en

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SAL: This is Sal again, and
this part four on the series

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that we're doing at
Stanford Medical School,

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with Doctor Connolly.

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DR. CONNOLLY: All right
Sal, we're back here again.

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This is now the
fourth of the slides.

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And this would be
now the business

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for why that segment
of colon was removed.

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This is the colon cancer.

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SAL: Wow, wow.

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DR. CONNOLLY: And
so just to orient,

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we'll go now to the drawing.

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Which is, like you were
saying before, up here

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this is the lumen.

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SAL: Right.

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DR. CONNOLLY: Up here.

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Out here, that's the--

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SAL: Lumen is the
inside of the colon.

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DR. CONNOLLY: The inside.

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That's the inside.

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Out here, this is the
rest of your belly.

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SAL: Right.

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DR. CONNOLLY: Where
the bowel is all kind

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of rotating around
in the abdomen.

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And so--

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SAL: Is there a word for
like intra-abdominal--

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DR. CONNOLLY: Yeah, peritoneal.

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SAL: Peritoneal, OK.

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DR. CONNOLLY: The
peritoneal cavity

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is where all the bowel loops are
kind of just moseying around.

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And then what we
have here is, this

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is an important
part, which is this

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is the muscle that
allows peristalsis.

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SAL: Yes, that's the peri-- I
learned that in high school.

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That's the kind of moving,
the undulating motion

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to the push stuff.

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DR. CONNOLLY: Yep.

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It'll go and it'll
sort of milk it along

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in order for the
contents to move along.

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So you can see, the muscle
looks all fine there.

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That's how thick
it's supposed to be.

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And it all looks fine over here.

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SAL: Just on a scale,
what scale is this?

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Like how thick is that muscle?

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DR. CONNOLLY: So
we're now, once again,

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our tiny little red blood cells
are those little dots there.

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SAL: Right.

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DR. CONNOLLY: So we're
talking about the thickness

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here as a few millimeters.

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SAL: That muscle is
about a few millimeters.

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DR. CONNOLLY: Remember
back to this guy,

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that was about six millimeters.

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So that's about six--

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SAL: OK, OK.

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DR. CONNOLLY: Millimeters thick.

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That's actually strong.

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That's a very,
very strong muscle.

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And you can kind of
see it goes up here,

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it kind of comes
around here, but it's

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looking like it's troubled
all along this area.

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SAL: Yes.

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And this stuff, all this stuff,
this once was probably a polyp,

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and now it's turned into a
kind of this massive polyp?

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DR. CONNOLLY: Yeah, so we
have the normal over here,

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for the lining.

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This is where it's
going dysplastic.

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It's looking a
little bit bad there.

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There's where it's
going dysplastic.

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And so now what
happens is, you've

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got these edges of dysplasia--

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SAL: When people in the
medical field say plastic,

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they're saying, that
word means tissue?

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DR. CONNOLLY: Well plastic in
general, like plastic surgery,

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or the plastics as far
as a material science,

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means moldable.

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SAL: I see.

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DR. CONNOLLY: But it also
means you can grow with it,

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and it can change shape.

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SAL: Right.

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So when you call something
plastic it's moldable tissue.

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DR. CONNOLLY: It's
the shape change.

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SAL: It's a shape change.

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I see.

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DR. CONNOLLY: And so the
shape changes were wrong.

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SAL: I see.

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DR. CONNOLLY: And
actually dysplasia

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can refer to a cell, a tissue,
an organ, or an entire limb.

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SAL: Oh, OK.

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DR. CONNOLLY: So it just
means it grew wrong.

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Or molded wrong.

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So now this is where we
have the cell dysplasia.

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This is all the bad stuff.

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And it basically started
probably somewhere up there,

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and is invading in all
of these directions.

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SAL: This one cell
up there just started

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dividing uncontrollably--

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DR. CONNOLLY: That's right.

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SAL: And it's descendants.

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DR. CONNOLLY: It could
have started from one cell

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being very bad.

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It often though starts--
and I'm going to change now,

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so we'll lose our art, and
so what I'm going to do

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is change this-- that
it often starts, though,

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from one of these.

00:03:04.130 --> 00:03:08.980
Meaning maybe a cell went
bad right around there.

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And now really is
starting to grow.

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SAL: And when you say grow,
it's not just one cell,

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it's all of its descendants.

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DR. CONNOLLY: It's descendants.

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And billions of
cells are growing.

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Billions and billions
are growing downward

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in order to now, in this case,
grow all the way through.

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SAL: Wow.

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DR. CONNOLLY: And so you can see
the scale is, it not only grew

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a little bit, it went
right through the muscle.

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So going back to this
guy here, this is now--

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SAL: And there
are some, the body

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does have things to fight this
off, but it was unsuccessful.

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DR. CONNOLLY: Oh that's right.

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And so there are
certain conditions

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where if you decrease the immune
functions, you'll get cancer.

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And so it's still argued
though whether it's

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that your immune system is
decreased, you got a virus,

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and then the virus
caused the cancer.

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Or whether there's a
lot of surveillance

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there to eliminate cancer.

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SAL: And the whole notion that
viruses-- it's fascinating.

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It's because viruses
are messing with our--

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isn't a significant chunk of our
own DNA from ancient viruses?

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DR. CONNOLLY: Yep.

00:04:06.650 --> 00:04:10.450
And I think there's a couple
big categories is that viruses

00:04:10.450 --> 00:04:13.260
can get into your DNA and
really screw up the DNA.

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Like getting integrated into it.

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But they also, like we said
before, can lead to irritation.

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And then more cell growth
and have trouble there.

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SAL: Makes sense, makes sense.

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DR. CONNOLLY: So
now we're back here,

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in which we're
looking at the cancer.

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Which probably, like
you said, started here.

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And is growing,
including spreading out

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all the normal tissue around it.

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SAL: Wow.

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DR. CONNOLLY: And so we're
going to look now at the cells.

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So zoom in.

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Zoom time.

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Hang on to your hat.

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OK, so what we're going
to do is first-- probably

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go into a lower power here--
is look at the edges of this.

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So once again, we find normal.

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And so this is even
not perfectly normal,

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you can see it's a
little bit dividing

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and a little bit irritated.

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So this is irritated
along the edge.

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SAL: Hyperplasia.

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DR. CONNOLLY: Exactly.

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SAL: I'm like, I'm
learning something.

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DR. CONNOLLY: All right.

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So then what we have now
is, as you go in deeper,

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these are the areas
which are normal,

00:05:03.380 --> 00:05:05.345
but this is all
kind of coming out.

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Like we were saying
up here, kind

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of growing out in
all directions.

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This is now where you can see
the cancer, next to the normal.

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You know we had talked
before about dysplasia.

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This is really bad.

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SAL: With a capital B.

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DR. CONNOLLY: Yep.

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Small children off
the street could

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be able to tell you
that this is bad.

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SAL: Right.

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After they watch this video.

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DR. CONNOLLY: Exactly.

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And so these are
the normal ones.

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They're doing their J-O-B job.

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Making the mucin,
nuclei at the bottom.

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What is this guy doing?

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It's just chaos.

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So before we talk
about carcinoma

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in situ, a cancer in spot.

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If you saw cells this bad, you'd
say do not let them go far.

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Because they will have
a tendency to invade.

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They're crazy.

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So this right here's a
bunch of the cells, that's

00:05:45.980 --> 00:05:48.290
a bunch of the cells,
they're these guys here.

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You can see they're really
haphazard, they're growing,

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they're not doing their--

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SAL: So if we found a polyp
that had this stuff that

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didn't cross that boundary line
yet, we still would say no,

00:05:59.870 --> 00:06:02.790
we've got to take this-- Well
I guess we already took it out.

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DR. CONNOLLY: We took it out.

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So cancer of the colon
is one of the ones where

00:06:06.440 --> 00:06:08.550
surgical cure is
still a classic.

00:06:08.550 --> 00:06:10.790
Cut it out, and you're
probably in pretty good shape.

00:06:10.790 --> 00:06:11.900
And so there you'd
say, well if it's

00:06:11.900 --> 00:06:13.320
the tip of the polyp
that looked like this,

00:06:13.320 --> 00:06:14.470
I think we got it out.

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But you'd say to yourself,
we better watch this person.

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SAL: I see.

00:06:16.760 --> 00:06:18.635
So if the whole polyp
kind of looked like that,

00:06:18.635 --> 00:06:20.060
you're like, oh let's
cut out a bigger section.

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DR. CONNOLLY: Yeah
then you might.

00:06:20.780 --> 00:06:22.380
So if it's going
down into the neck,

00:06:22.380 --> 00:06:24.088
or getting a little
further, or if you've

00:06:24.088 --> 00:06:26.240
cut across it at the
margin, then watch out.

00:06:26.240 --> 00:06:27.630
But here's the problem.

00:06:27.630 --> 00:06:30.520
Is remember how I said up
here it's not a big deal,

00:06:30.520 --> 00:06:33.180
but once you get down near
the veins and arteries?

00:06:33.180 --> 00:06:37.171
These guys are running amok
down by the veins, the arteries.

00:06:37.171 --> 00:06:39.670
SAL: And so you can actually
see these cells have split off.

00:06:39.670 --> 00:06:40.730
And they're infiltrating.

00:06:40.730 --> 00:06:40.880
Wow.

00:06:40.880 --> 00:06:42.370
DR. CONNOLLY: So you
can see these guys here.

00:06:42.370 --> 00:06:43.920
So that's one little
nest of cells.

00:06:43.920 --> 00:06:45.300
There's one.

00:06:45.300 --> 00:06:47.290
That's probably, right
there, a cancer cell

00:06:47.290 --> 00:06:49.364
just dying to get
into that little vein.

00:06:49.364 --> 00:06:51.780
SAL: So this is actually, I
can never say the word, meta--

00:06:51.780 --> 00:06:52.340
DR. CONNOLLY: Metastasis.

00:06:52.340 --> 00:06:52.840
SAL: This is it.

00:06:52.840 --> 00:06:53.580
We're seeing it.

00:06:53.580 --> 00:06:54.640
DR. CONNOLLY: This is
where it would come from.

00:06:54.640 --> 00:06:55.730
SAL: This is where it's
starting to happen.

00:06:55.730 --> 00:06:57.688
DR. CONNOLLY: So these
guys are the bad actors.

00:06:57.688 --> 00:07:00.860
They're growing in next to
these very fragile little blood

00:07:00.860 --> 00:07:03.280
vessels, and so that guy
is knocking on the door.

00:07:03.280 --> 00:07:07.380
Once he gets in here, that's a
venule, meaning a little vein.

00:07:07.380 --> 00:07:08.340
That's the road out.

00:07:08.340 --> 00:07:08.600
SAL: Right.

00:07:08.600 --> 00:07:10.275
And it just looks like a
circle here because it's

00:07:10.275 --> 00:07:11.710
a two-dimensional
cross-section of it,

00:07:11.710 --> 00:07:13.770
but you can imagine it popping
in and out of our screen.

00:07:13.770 --> 00:07:13.970
DR. CONNOLLY: Yes.

00:07:13.970 --> 00:07:14.800
It would be popping in
and out of our screen.

00:07:14.800 --> 00:07:16.740
So this guy would kind of
go in and out of the screen,

00:07:16.740 --> 00:07:18.880
connect to this one, and
then it would go out.

00:07:18.880 --> 00:07:20.463
SAL: And it's
officially-- I can never

00:07:20.463 --> 00:07:22.400
say the word--
metastasized once it's

00:07:22.400 --> 00:07:23.835
found a beachhead
someplace else?

00:07:23.835 --> 00:07:24.960
DR. CONNOLLY: That's right.

00:07:24.960 --> 00:07:27.030
So it's considered
a metastasis where,

00:07:27.030 --> 00:07:30.710
let's say, the cell got into the
vessel, if it left the region.

00:07:30.710 --> 00:07:33.260
So it went to the
lung, the liver.

00:07:33.260 --> 00:07:34.930
This is looking
like you really are

00:07:34.930 --> 00:07:36.490
worried that this
could metastasize.

00:07:36.490 --> 00:07:36.800
SAL: Right.

00:07:36.800 --> 00:07:38.424
DR. CONNOLLY: And so
what's interesting

00:07:38.424 --> 00:07:40.910
about this is that when you
look at something like this,

00:07:40.910 --> 00:07:44.065
there's such a thing
called, for cancer, grade.

00:07:44.065 --> 00:07:45.690
And what grade is,
is basically what we

00:07:45.690 --> 00:07:47.520
we've been just talking
about, how bad does that look?

00:07:47.520 --> 00:07:48.190
SAL: Right.

00:07:48.190 --> 00:07:50.780
DR. CONNOLLY: And so the grade
is, wow, that looks nasty.

00:07:50.780 --> 00:07:51.420
I think that--

00:07:51.420 --> 00:07:52.866
SAL: Is nasty a technical term?

00:07:52.866 --> 00:07:54.740
DR. CONNOLLY: Actually
we use it quite a bit.

00:07:54.740 --> 00:07:55.810
Some people say, oh what
did that tumor show?

00:07:55.810 --> 00:07:56.840
We say it was nasty.

00:07:56.840 --> 00:07:59.850
When we talk about nastiness,
it's a lack of behavior.

00:07:59.850 --> 00:08:02.800
If you can get a cell where
the nucleus gets that big,

00:08:02.800 --> 00:08:06.010
or sometimes it's that
big, there's chaos.

00:08:06.010 --> 00:08:08.140
And there's chaos not
just in nuclear size,

00:08:08.140 --> 00:08:08.985
but how it behaves.

00:08:08.985 --> 00:08:10.360
SAL: And I guess
the nuclear size

00:08:10.360 --> 00:08:13.390
is a telltale, because that
means that the cell is devoting

00:08:13.390 --> 00:08:15.602
a lot of its resources
for replication and--

00:08:15.602 --> 00:08:17.060
DR. CONNOLLY: It's
for replication,

00:08:17.060 --> 00:08:19.660
but it also means, to me, that
normally things in the cellar

00:08:19.660 --> 00:08:20.850
are very orderly.

00:08:20.850 --> 00:08:24.310
You do not divide your DNA
until these things are already

00:08:24.310 --> 00:08:24.980
[INAUDIBLE].

00:08:24.980 --> 00:08:27.040
And now it's just
left and right.

00:08:27.040 --> 00:08:30.010
So yeah, this would
be a high grade tumor.

00:08:30.010 --> 00:08:31.990
And then stage is
the other main thing.

00:08:31.990 --> 00:08:33.240
SAL: Yes, I've heard of stage.

00:08:33.240 --> 00:08:35.960
DR. CONNOLLY: Stage means,
where is it in the body?

00:08:35.960 --> 00:08:41.770
So in this case, if it's these
nasty cells at the very top,

00:08:41.770 --> 00:08:44.960
it's actually a lower stage
then if they're nasty cells

00:08:44.960 --> 00:08:46.960
and they've come all
the way down here.

00:08:46.960 --> 00:08:49.622
SAL: So in situ carcinoma
would still get a stage.

00:08:49.622 --> 00:08:50.830
DR. CONNOLLY: It's a stage 0.

00:08:50.830 --> 00:08:51.660
SAL: Stage 0.

00:08:51.660 --> 00:08:53.760
DR. CONNOLLY: So it's
basically you're nowhere.

00:08:53.760 --> 00:08:56.870
And then if you begin to
just cross over, like here,

00:08:56.870 --> 00:08:58.830
and invade, then
you're in stage 1.

00:08:58.830 --> 00:09:00.980
And then there are depths
as you go for stages.

00:09:00.980 --> 00:09:02.720
And then there's
always the other thing,

00:09:02.720 --> 00:09:05.160
where did it go off to
other parts of your body.

00:09:05.160 --> 00:09:06.780
And that's the
very highest stage.

00:09:06.780 --> 00:09:08.490
SAL: And so this
isn't a-- and this

00:09:08.490 --> 00:09:10.500
is true of all cancers, when
people about breast cancer,

00:09:10.500 --> 00:09:12.000
I've heard it in
that context a lot.

00:09:12.000 --> 00:09:14.520
Stage 1, or stage 0 through 4.

00:09:14.520 --> 00:09:15.740
So it isn't just the size.

00:09:15.740 --> 00:09:20.700
If the cancerous tissue is big,
but if it's in a safe place,

00:09:20.700 --> 00:09:22.317
it could still be
stage 1 or stage 0.

00:09:22.317 --> 00:09:23.150
DR. CONNOLLY: It is.

00:09:23.150 --> 00:09:26.060
What's interesting about staging
is almost the whole world

00:09:26.060 --> 00:09:29.490
has agreed to do the
same kind of staging.

00:09:29.490 --> 00:09:34.750
And that staging is
what we're calling TNM.

00:09:34.750 --> 00:09:38.390
And T has to do with how
big it is, and the one site,

00:09:38.390 --> 00:09:40.280
and how much it's
crossed any barriers.

00:09:40.280 --> 00:09:40.780
SAL: Right.

00:09:40.780 --> 00:09:42.700
But the barrier crossing sounds
like the most important thing.

00:09:42.700 --> 00:09:43.616
DR. CONNOLLY: It does.

00:09:43.616 --> 00:09:45.800
Although this one here is,
are they in lymph nodes?

00:09:45.800 --> 00:09:46.530
SAL: Oh, right.

00:09:46.530 --> 00:09:47.905
DR. CONNOLLY: And
the lymph nodes

00:09:47.905 --> 00:09:50.020
are nearby structures
where the lymph goes.

00:09:50.020 --> 00:09:51.960
And so that's one road out.

00:09:51.960 --> 00:09:54.170
And the other one is metastases.

00:09:54.170 --> 00:09:57.260
And so yeah, the staging
has to do with all three.

00:09:57.260 --> 00:09:57.970
SAL: I see.

00:09:57.970 --> 00:09:59.917
And metastases always
happens through

00:09:59.917 --> 00:10:02.250
the circulatory system--
Through the blood, the vessels?

00:10:02.250 --> 00:10:04.000
Or does it also happen
through the lymph network?

00:10:04.000 --> 00:10:04.980
DR. CONNOLLY: And
so it's something

00:10:04.980 --> 00:10:07.690
where going through the lymph
nodes, for something like this,

00:10:07.690 --> 00:10:09.290
is one of the first steps.

00:10:09.290 --> 00:10:11.500
But getting to the
liver and the lung,

00:10:11.500 --> 00:10:14.290
it's got to get into the
blood vessels somehow.

00:10:14.290 --> 00:10:17.850
The lymphatic in your colon
connects to a local lymph node,

00:10:17.850 --> 00:10:20.300
but does not connect through
lymph only to the lung.

00:10:20.300 --> 00:10:20.800
SAL: I see.

00:10:20.800 --> 00:10:23.350
DR. CONNOLLY: So it must have
gone into the blood somewhere.

00:10:23.350 --> 00:10:25.530
So that's the way it looks here.

00:10:25.530 --> 00:10:28.110
And then the final thing here,
when looking at this cancer,

00:10:28.110 --> 00:10:33.410
is if we go over here, this is
the greatest depth of invasion.

00:10:33.410 --> 00:10:36.060
You had asked me about the
body's immune function.

00:10:36.060 --> 00:10:39.600
Well if you look here, now
you see how it's kind of loose

00:10:39.600 --> 00:10:41.434
and there are all these
little immune cells?

00:10:41.434 --> 00:10:42.558
That's what these guys are.

00:10:42.558 --> 00:10:43.150
Those are--

00:10:43.150 --> 00:10:43.740
SAL: What's the immune cell?

00:10:43.740 --> 00:10:44.460
DR. CONNOLLY: These guys here.

00:10:44.460 --> 00:10:45.549
See the little round guys?

00:10:45.549 --> 00:10:46.465
Those are lymphocytes.

00:10:46.465 --> 00:10:46.965
SAL: I see.

00:10:46.965 --> 00:10:49.030
I should circle it, actually.

00:10:49.030 --> 00:10:51.610
How can you tell the difference
between the lymphocytes

00:10:51.610 --> 00:10:53.030
and the cancer cells?

00:10:53.030 --> 00:10:53.880
DR. CONNOLLY: That's
because I'm a pathologist.

00:10:53.880 --> 00:10:56.130
SAL: That's because you've
had many years of training.

00:10:56.130 --> 00:10:58.296
DR. CONNOLLY: No, but they're
the little round ones.

00:10:58.296 --> 00:11:00.140
So this one right here
is a classic cell,

00:11:00.140 --> 00:11:02.510
which is called a plasma
cell, in which there's

00:11:02.510 --> 00:11:05.532
a nucleus here, and all the rest
of this is making antibodies.

00:11:05.532 --> 00:11:06.990
SAL: You're not
circling that area?

00:11:06.990 --> 00:11:08.480
DR. CONNOLLY: No,
I'm just drawing.

00:11:08.480 --> 00:11:08.585
SAL: Oh, OK.

00:11:08.585 --> 00:11:09.418
You're just drawing.

00:11:09.418 --> 00:11:11.320
DR. CONNOLLY: So
this guy is this one.

00:11:11.320 --> 00:11:12.070
I drew him right--

00:11:12.070 --> 00:11:13.640
SAL: OK, you're
zooming in on this.

00:11:13.640 --> 00:11:14.420
DR. CONNOLLY: Yeah,
zooming in on that.

00:11:14.420 --> 00:11:17.420
So yeah, that's a plasma
cell, meaning it's a nucleus--

00:11:17.420 --> 00:11:18.760
SAL: I just want to clarify,
what you've circled there,

00:11:18.760 --> 00:11:20.759
just because it could be
a little bit confusing,

00:11:20.759 --> 00:11:22.940
but we have this big circle
is maybe we [INAUDIBLE].

00:11:22.940 --> 00:11:24.060
DR. CONNOLLY: This is why I
should leave it to the pros.

00:11:24.060 --> 00:11:25.720
SAL: No, just because
I'm getting confused.

00:11:25.720 --> 00:11:27.060
You're not circling that area.

00:11:27.060 --> 00:11:27.930
DR. CONNOLLY: No, no,
I'm not doing that.

00:11:27.930 --> 00:11:29.940
SAL: You were just showing
what it looks like zoomed in.

00:11:29.940 --> 00:11:31.505
DR. CONNOLLY: Right, so
that's a plasma cell.

00:11:31.505 --> 00:11:32.730
SAL: That's a plasma cell.

00:11:32.730 --> 00:11:34.729
DR. CONNOLLY: That's
making antibodies, probably

00:11:34.729 --> 00:11:35.700
against the tumor.

00:11:35.700 --> 00:11:38.797
And so that's the immune
response in that spot.

00:11:38.797 --> 00:11:40.880
SAL: And how do you know
that's-- That looked very

00:11:40.880 --> 00:11:43.022
similar to the
cancerous cells to me.

00:11:43.022 --> 00:11:44.980
DR. CONNOLLY: This one's
a little hard to tell.

00:11:44.980 --> 00:11:47.410
And if you had a real microscope
you'd turn up the light.

00:11:47.410 --> 00:11:50.260
And we'd have a very
specific look to the nucleus.

00:11:50.260 --> 00:11:52.615
And then these guys over here
have little pink granules

00:11:52.615 --> 00:11:56.080
in them, which is a
type of immune cell.

00:11:56.080 --> 00:11:57.767
And so when looking
through here--

00:11:57.767 --> 00:11:59.850
SAL: On this depth, which
ones are cancerous here?

00:11:59.850 --> 00:12:02.240
DR. CONNOLLY: OK, so now
let me just get over here,

00:12:02.240 --> 00:12:05.820
to this one here, and then
come out just a little bit.

00:12:05.820 --> 00:12:07.880
Let me go over here.

00:12:07.880 --> 00:12:09.360
Is that when looking
at these guys,

00:12:09.360 --> 00:12:10.760
these are all inflammation.

00:12:10.760 --> 00:12:13.310
The nearest cancer cell
where I could bet the farm

00:12:13.310 --> 00:12:14.270
are these guys up here.

00:12:14.270 --> 00:12:14.690
SAL: Oh, OK.

00:12:14.690 --> 00:12:16.620
See, when you see on this
view it becomes more obvious.

00:12:16.620 --> 00:12:17.560
They definitely look different.

00:12:17.560 --> 00:12:18.210
DR. CONNOLLY: They
look different.

00:12:18.210 --> 00:12:20.330
And so then when you come
out here, you can see,

00:12:20.330 --> 00:12:21.650
there's the cancer.

00:12:21.650 --> 00:12:24.160
This is the body's reaction
to the cancer right there.

00:12:24.160 --> 00:12:24.940
SAL: I see.

00:12:24.940 --> 00:12:26.490
DR. CONNOLLY: At
the deepest zone.

00:12:26.490 --> 00:12:28.180
And there are therapies
based on trying

00:12:28.180 --> 00:12:30.420
to get more of this
immune response.

00:12:30.420 --> 00:12:32.910
SAL: That's amazing.

00:12:32.910 --> 00:12:34.700
Very cool.


Colon dysplasia

WEBVTT
Kind: captions
Language: en

00:00:00.000 --> 00:00:02.550
SAL: This is Sal, and I'm
still at Stanford Medical

00:00:02.550 --> 00:00:03.824
School with Dr. Connolly.

00:00:03.824 --> 00:00:05.990
DOCTOR CONNOLLY: Sal, we're
going to continue going.

00:00:05.990 --> 00:00:08.510
You going to get one
unit of credit for today.

00:00:08.510 --> 00:00:09.450
SAL: Excellent.

00:00:09.450 --> 00:00:10.932
My mother would be proud.

00:00:10.932 --> 00:00:13.140
DOCTOR CONNOLLY: So what
we're going to look at today

00:00:13.140 --> 00:00:15.200
is a colon polyp.

00:00:15.200 --> 00:00:16.810
We had said before
polyp is something

00:00:16.810 --> 00:00:18.740
that's going to
stick up like this.

00:00:18.740 --> 00:00:21.470
SAL: So in that last video
we saw, it was not a polyp.

00:00:21.470 --> 00:00:24.896
That was like an irritated
part of the bowel?

00:00:24.896 --> 00:00:25.830
DOCTOR CONNOLLY: Yeah.

00:00:25.830 --> 00:00:26.980
It was very low lying.

00:00:26.980 --> 00:00:27.560
It was--

00:00:27.560 --> 00:00:29.080
SAL: Let me get
you the pen here.

00:00:29.080 --> 00:00:30.280
We've got it all tangled up.

00:00:30.280 --> 00:00:31.946
DOCTOR CONNOLLY: It
was really just kind

00:00:31.946 --> 00:00:33.820
of a patch of
irritant right there.

00:00:33.820 --> 00:00:34.320
SAL: I see.

00:00:34.320 --> 00:00:35.840
DOCTOR CONNOLLY: So we've
got a bigger piece now.

00:00:35.840 --> 00:00:36.270
SAL: I see.

00:00:36.270 --> 00:00:38.010
That's why it just looks--
everything is more--

00:00:38.010 --> 00:00:39.950
DOCTOR CONNOLLY: So you can see
the glands look tiny in here.

00:00:39.950 --> 00:00:42.740
SAL: So roughly that last slide,
how big would it be on this?

00:00:42.740 --> 00:00:45.860
DOCTOR CONNOLLY: It would
be about a piece like that.

00:00:45.860 --> 00:00:48.780
To be fair, it
probably was what was

00:00:48.780 --> 00:00:50.810
underlying this area right here.

00:00:50.810 --> 00:00:51.941
SAL: I see.

00:00:51.941 --> 00:00:53.440
DOCTOR CONNOLLY:
And then it grew on

00:00:53.440 --> 00:00:54.975
to be something more than that.

00:00:54.975 --> 00:00:56.500
SAL: It wasn't this exact one.

00:00:56.500 --> 00:00:57.260
DOCTOR CONNOLLY: No, it wasn't.

00:00:57.260 --> 00:00:59.290
SAL: It could grow on to be
something like this polyp.

00:00:59.290 --> 00:00:59.820
DOCTOR CONNOLLY: It
could grow into this.

00:00:59.820 --> 00:01:03.130
So this is something where
when we have a colon resection,

00:01:03.130 --> 00:01:05.210
if there's a cancer,
often there's a polyp.

00:01:05.210 --> 00:01:05.710
SAL: Right.

00:01:05.710 --> 00:01:07.410
DOCTOR CONNOLLY: There's
an area of that patch

00:01:07.410 --> 00:01:08.642
like we saw with hyperplasia.

00:01:08.642 --> 00:01:10.350
SAL: Not necessarily
where the cancer is?

00:01:10.350 --> 00:01:11.840
It's in that same
section of colon.

00:01:11.840 --> 00:01:12.756
DOCTOR CONNOLLY: Yeah.

00:01:12.756 --> 00:01:14.910
We find that people, if
they have colon cancer,

00:01:14.910 --> 00:01:18.522
often they have lots of
other pre-cancer lesions.

00:01:18.522 --> 00:01:19.230
And you can see--

00:01:19.230 --> 00:01:19.729
SAL: I see.

00:01:19.729 --> 00:01:22.010
Their bowels are just going
through a lot of trauma.

00:01:22.010 --> 00:01:24.260
DOCTOR CONNOLLY: Some of
it's familial susceptibility,

00:01:24.260 --> 00:01:27.530
but a lot of it is that they are
showing a propensity to this.

00:01:27.530 --> 00:01:30.000
I don't know if it's from
environmental exposures

00:01:30.000 --> 00:01:30.520
or what.

00:01:30.520 --> 00:01:31.100
SAL: I see.

00:01:31.100 --> 00:01:34.220
And just to remind myself
on what we're doing here,

00:01:34.220 --> 00:01:37.120
so you cut out a
bit of colon-- you

00:01:37.120 --> 00:01:39.070
can kind of view it as
a tube-- because there

00:01:39.070 --> 00:01:40.210
was some cancer there.

00:01:40.210 --> 00:01:40.610
DOCTOR CONNOLLY: Right.

00:01:40.610 --> 00:01:42.985
SAL: And then this thing might
be some other polyp that's

00:01:42.985 --> 00:01:44.810
sitting in that same
section you cut out.

00:01:44.810 --> 00:01:45.080
DOCTOR CONNOLLY: Yeah.

00:01:45.080 --> 00:01:46.980
SAL: And maybe that
second slide we

00:01:46.980 --> 00:01:48.710
saw with the irritation, that
could be like right there.

00:01:48.710 --> 00:01:49.100
I see.

00:01:49.100 --> 00:01:50.558
DOCTOR CONNOLLY:
As matter of fact,

00:01:50.558 --> 00:01:54.210
it's important that you
normally wouldn't see this slide

00:01:54.210 --> 00:01:59.250
in a patient, because almost
all polyps, the colonoscopist

00:01:59.250 --> 00:02:00.540
is coming in.

00:02:00.540 --> 00:02:03.504
And they remove it
through the colonoscope.

00:02:03.504 --> 00:02:05.920
SAL: I see, because they don't
know whether it's cancerous

00:02:05.920 --> 00:02:06.250
or not.

00:02:06.250 --> 00:02:06.870
DOCTOR CONNOLLY:
They'll remove it,

00:02:06.870 --> 00:02:08.328
but you wouldn't
see the full wall.

00:02:08.328 --> 00:02:10.137
So right out here--
I mean, that's

00:02:10.137 --> 00:02:11.720
all the way through
the wall and which

00:02:11.720 --> 00:02:14.051
you've got muscle up here.

00:02:14.051 --> 00:02:14.550
SAL: I see

00:02:14.550 --> 00:02:16.800
DOCTOR CONNOLLY: That's the
muscular part of the wall.

00:02:16.800 --> 00:02:19.260
And so this is, really,
kind of going down

00:02:19.260 --> 00:02:21.200
to a full piece of the wall.

00:02:21.200 --> 00:02:21.800
SAL: I see.

00:02:21.800 --> 00:02:22.779
Wow.

00:02:22.779 --> 00:02:24.570
DOCTOR CONNOLLY: So
this is a larger piece,

00:02:24.570 --> 00:02:26.660
and this is in order
to show the polyp

00:02:26.660 --> 00:02:28.804
in its natural environment.

00:02:28.804 --> 00:02:30.220
So what we're going
to do is we're

00:02:30.220 --> 00:02:32.850
going to begin looking
at the polyp here.

00:02:32.850 --> 00:02:37.560
And so we'll first
start way out here,

00:02:37.560 --> 00:02:41.641
which is to go back again
to the normal architecture.

00:02:41.641 --> 00:02:42.140
SAL: Right.

00:02:42.140 --> 00:02:44.230
DOCTOR CONNOLLY: So we had said
there are supposed to be tubes.

00:02:44.230 --> 00:02:45.844
Luckily, this one,
it's cut right

00:02:45.844 --> 00:02:47.010
down the middle of the tube.

00:02:47.010 --> 00:02:49.370
So you can see how big the
hole is supposed to be.

00:02:49.370 --> 00:02:52.340
And so this is normal
architecture there.

00:02:52.340 --> 00:02:54.520
And then if I just
go out a little bit

00:02:54.520 --> 00:02:56.590
and I'm just going
to come along,

00:02:56.590 --> 00:02:59.795
you can see that you
have an area here

00:02:59.795 --> 00:03:01.580
in which there was
a bit of irritation.

00:03:01.580 --> 00:03:04.450
So it's thrown up a little
bit like we saw before,

00:03:04.450 --> 00:03:08.100
but the real trouble is
this thing sticking out.

00:03:08.100 --> 00:03:08.600
SAL: Right.

00:03:08.600 --> 00:03:09.530
DOCTOR CONNOLLY:
And we wonder what

00:03:09.530 --> 00:03:11.150
is that thing sticking out.

00:03:11.150 --> 00:03:13.290
And so for the
medical students, we

00:03:13.290 --> 00:03:16.270
try to tell them to think like
the way the pathologist would

00:03:16.270 --> 00:03:20.136
be, that you first need to look
at the overall architecture.

00:03:20.136 --> 00:03:21.510
This is an abnormal
architecture.

00:03:21.510 --> 00:03:21.790
SAL: Yes.

00:03:21.790 --> 00:03:22.022
DOCTOR CONNOLLY:
You don't usually

00:03:22.022 --> 00:03:23.590
have bumps sticking out.

00:03:23.590 --> 00:03:25.302
Then the next thing
you're going to do--

00:03:25.302 --> 00:03:27.010
SAL: In 3D it would
look like a mushroom?

00:03:27.010 --> 00:03:27.600
DOCTOR CONNOLLY: Yeah.

00:03:27.600 --> 00:03:28.975
So it would look
like a mushroom.

00:03:28.975 --> 00:03:31.800
Actually, they tend to have
foldings on the top of them,

00:03:31.800 --> 00:03:33.986
so a little more like
cauliflower, because they

00:03:33.986 --> 00:03:35.390
tend to be cauliflower colored.

00:03:35.390 --> 00:03:35.770
SAL: I see.

00:03:35.770 --> 00:03:37.080
DOCTOR CONNOLLY: So then
when you look here--

00:03:37.080 --> 00:03:38.160
SAL: That color, too?

00:03:38.160 --> 00:03:38.410
DOCTOR CONNOLLY: Yeah.

00:03:38.410 --> 00:03:39.868
They don't have
much color to them.

00:03:39.868 --> 00:03:43.920
In fact, the colonoscopist,
when they look at a polyp,

00:03:43.920 --> 00:03:46.200
can kind of tell if
there's a chance of cancer,

00:03:46.200 --> 00:03:48.544
because they begin having
weird blood vessel samples.

00:03:48.544 --> 00:03:50.960
SAL: And just to be clear,
they're not this purplish color

00:03:50.960 --> 00:03:52.120
that we're seeing on this slide.

00:03:52.120 --> 00:03:52.940
DOCTOR CONNOLLY: No.

00:03:52.940 --> 00:03:53.650
SAL: This is color added.

00:03:53.650 --> 00:03:54.650
DOCTOR CONNOLLY:
Thin section and we

00:03:54.650 --> 00:03:56.691
had to put the-- it would
be colorless otherwise,

00:03:56.691 --> 00:03:58.280
so we had to put a stain on it.

00:03:58.280 --> 00:03:58.340
SAL: Right, right.

00:03:58.340 --> 00:03:59.140
Makes sense.

00:03:59.140 --> 00:03:59.880
DOCTOR CONNOLLY: So now
what I'm going to do

00:03:59.880 --> 00:04:01.622
is I'm going to
draw the area where

00:04:01.622 --> 00:04:02.830
I'm going to do a comparison.

00:04:02.830 --> 00:04:03.920
See this thingamabob here?

00:04:03.920 --> 00:04:04.320
SAL: Yeah.

00:04:04.320 --> 00:04:04.540
DOCTOR CONNOLLY:
You're going too--

00:04:04.540 --> 00:04:05.290
SAL: Look at that.

00:04:05.290 --> 00:04:06.331
DOCTOR CONNOLLY: So now--

00:04:06.331 --> 00:04:07.460
SAL: Miracles of science.

00:04:07.460 --> 00:04:08.376
DOCTOR CONNOLLY: Yeah.

00:04:08.376 --> 00:04:09.780
SAL: Technology.

00:04:09.780 --> 00:04:11.820
DOCTOR CONNOLLY:
So these are cells

00:04:11.820 --> 00:04:13.580
which are relatively normal.

00:04:13.580 --> 00:04:15.630
These are cells
which are abnormal.

00:04:15.630 --> 00:04:18.079
And when we look them, a
pathologist immediately

00:04:18.079 --> 00:04:19.700
says these look angry.

00:04:19.700 --> 00:04:20.779
SAL: They do.

00:04:20.779 --> 00:04:21.860
I would say that, too.

00:04:21.860 --> 00:04:22.790
DOCTOR CONNOLLY: And
so when you look-- so

00:04:22.790 --> 00:04:25.050
what's angry about
them is, first of all,

00:04:25.050 --> 00:04:28.540
they're not committed
to behaving.

00:04:28.540 --> 00:04:30.510
Proper behavior over here.

00:04:30.510 --> 00:04:33.490
Nuclei belong at the bottom.

00:04:33.490 --> 00:04:35.540
Things that you're supposed
to do for your job,

00:04:35.540 --> 00:04:37.221
J-O-B, are at the top.

00:04:37.221 --> 00:04:37.720
SAL: Yes.

00:04:37.720 --> 00:04:39.886
DOCTOR CONNOLLY: And so
when you look at these guys,

00:04:39.886 --> 00:04:42.320
it's like, where's your job?

00:04:42.320 --> 00:04:43.990
And so a few of them
are making mucin,

00:04:43.990 --> 00:04:47.606
but these ones have nuclei of
different sizes and shapes.

00:04:47.606 --> 00:04:48.106
SAL: Yeah.

00:04:48.106 --> 00:04:48.460
And they're all just--

00:04:48.460 --> 00:04:49.220
DOCTOR CONNOLLY: They're
just doing their own thing.

00:04:49.220 --> 00:04:50.380
SAL: They're not
even doing mucin.

00:04:50.380 --> 00:04:51.350
DOCTOR CONNOLLY:
No, some make mucin,

00:04:51.350 --> 00:04:53.490
but a lot of them all
they're doing is growing.

00:04:53.490 --> 00:04:56.180
And so usually there's
a playoff between that

00:04:56.180 --> 00:04:59.150
if you're committed
to your specific job--

00:04:59.150 --> 00:05:00.820
and we call it differentiation.

00:05:00.820 --> 00:05:01.570
SAL: Right, right.

00:05:01.570 --> 00:05:03.195
DOCTOR CONNOLLY: So
if you're committed

00:05:03.195 --> 00:05:04.940
to your differentiation,
you tend

00:05:04.940 --> 00:05:07.250
not to have as much
propensity to grow.

00:05:07.250 --> 00:05:08.742
And if you tend
to grow a lot, you

00:05:08.742 --> 00:05:10.200
tend not to do the
differentiation.

00:05:10.200 --> 00:05:13.310
And so this is
largely that you have

00:05:13.310 --> 00:05:16.280
this sort of chaos
of nuclei, less

00:05:16.280 --> 00:05:19.350
commitment to the
normal structures.

00:05:19.350 --> 00:05:21.300
And you're not
producing as much.

00:05:21.300 --> 00:05:24.640
And so what this, this
is now called dysplasia.

00:05:24.640 --> 00:05:25.532
SAL: Dysplasia.

00:05:25.532 --> 00:05:26.490
DOCTOR CONNOLLY: D-Y-S.

00:05:26.490 --> 00:05:27.820
SAL: Right, plasia
in the wrong thing.

00:05:27.820 --> 00:05:29.530
DOCTOR CONNOLLY: So
it's the wrong growth.

00:05:29.530 --> 00:05:30.670
And so that's what
we're saying is

00:05:30.670 --> 00:05:32.430
we don't like the
looks of these ones,

00:05:32.430 --> 00:05:36.310
and so these individual cells
look dysplastic and they grow.

00:05:36.310 --> 00:05:38.730
So then to tell
whether it's cancer,

00:05:38.730 --> 00:05:42.150
cancer means in this
organ that you've

00:05:42.150 --> 00:05:45.560
grown across this
line in the sand.

00:05:45.560 --> 00:05:48.340
SAL: So let me-- so
literally if you've

00:05:48.340 --> 00:05:50.390
crossed this boundary
right over here, cancer?

00:05:50.390 --> 00:05:51.348
DOCTOR CONNOLLY: Right.

00:05:51.348 --> 00:05:53.490
SAL: So even if I'm
in the polyp up here

00:05:53.490 --> 00:05:55.787
and I'm controlling
uncontrollably cancer cells

00:05:55.787 --> 00:05:57.620
and it's mutated and
it's not killing itself

00:05:57.620 --> 00:05:59.340
the way it's supposed
to, you still

00:05:59.340 --> 00:06:01.217
would not call it
officially cancer?

00:06:01.217 --> 00:06:02.050
DOCTOR CONNOLLY: No.

00:06:02.050 --> 00:06:06.700
So what happens is that there's
a middle term where it's

00:06:06.700 --> 00:06:10.180
a cancer still in
the usual place,

00:06:10.180 --> 00:06:13.000
and that's carcinoma in situ.

00:06:13.000 --> 00:06:13.699
SAL: I see.

00:06:13.699 --> 00:06:15.240
DOCTOR CONNOLLY: So
carcinoma in situ

00:06:15.240 --> 00:06:18.530
means it's not an
invasive cancer.

00:06:18.530 --> 00:06:21.590
And therefore, most people would
not really call it a cancer.

00:06:21.590 --> 00:06:23.890
It's just so wild
looking up here,

00:06:23.890 --> 00:06:25.470
you know that it
would do that if it

00:06:25.470 --> 00:06:27.321
was given any chance or time.

00:06:27.321 --> 00:06:27.820
SAL: I see.

00:06:27.820 --> 00:06:29.320
So what we're saying
is if something

00:06:29.320 --> 00:06:34.239
was out here, carcinoma
in situ, that eventually

00:06:34.239 --> 00:06:35.530
it probably would make its way.

00:06:35.530 --> 00:06:36.446
DOCTOR CONNOLLY: Yeah.

00:06:36.446 --> 00:06:38.000
It just looks so
committed to growth

00:06:38.000 --> 00:06:41.164
and so aggressive and so
little differentiation

00:06:41.164 --> 00:06:42.580
that you know if
you gave it time,

00:06:42.580 --> 00:06:43.620
you'd worry that it would grow.

00:06:43.620 --> 00:06:44.270
SAL: Makes sense.

00:06:44.270 --> 00:06:45.811
DOCTOR CONNOLLY: So
with here though,

00:06:45.811 --> 00:06:48.230
this is dysplasia, where
it's very upsetting

00:06:48.230 --> 00:06:50.130
that it's growing so fast.

00:06:50.130 --> 00:06:53.880
But what's important about this
is in hyperplasia, if you took

00:06:53.880 --> 00:06:56.880
away the stimulus or irritant,
it would go back to normal.

00:06:56.880 --> 00:06:57.611
This will not.

00:06:57.611 --> 00:06:58.110
SAL: I see.

00:06:58.110 --> 00:06:59.970
Like we said, if
there's some irritant

00:06:59.970 --> 00:07:01.412
unless we do--
like a week later,

00:07:01.412 --> 00:07:03.870
we had a couple weeks later
that hyperplasia would go away.

00:07:03.870 --> 00:07:05.350
Dysplasia is here to stay.

00:07:05.350 --> 00:07:06.599
DOCTOR CONNOLLY: That's right.

00:07:06.599 --> 00:07:08.334
And so the key word
we use is autonomous.

00:07:08.334 --> 00:07:09.000
SAL: Autonomous.

00:07:09.000 --> 00:07:09.843
It's independent.

00:07:09.843 --> 00:07:11.343
DOCTOR CONNOLLY:
It's just whatever.

00:07:11.343 --> 00:07:12.990
So it will grow no matter what.

00:07:12.990 --> 00:07:15.950
It doesn't care about clues
from neighboring cells.

00:07:15.950 --> 00:07:17.830
It doesn't need
something driving it.

00:07:17.830 --> 00:07:21.650
So what you have then
is this is growing.

00:07:21.650 --> 00:07:25.380
And if it's growing and it's
all by itself and growing,

00:07:25.380 --> 00:07:27.420
it's then called a neoplasia.

00:07:27.420 --> 00:07:29.420
So that's our last plasia.

00:07:29.420 --> 00:07:30.995
SAL: So neoplasia
showing dysplasia--

00:07:30.995 --> 00:07:31.870
DOCTOR CONNOLLY: Yep.

00:07:31.870 --> 00:07:34.800
So dysplasia just is
more of when you go in

00:07:34.800 --> 00:07:37.112
to look at these
guys, these features--

00:07:37.112 --> 00:07:37.612
SAL: Oh.

00:07:37.612 --> 00:07:38.903
It's like a particular feature.

00:07:38.903 --> 00:07:41.095
DOCTOR CONNOLLY: These
cells aren't growing right.

00:07:41.095 --> 00:07:42.720
SAL: So that's an
example of dysplasia.

00:07:42.720 --> 00:07:43.100
DOCTOR CONNOLLY: Right.

00:07:43.100 --> 00:07:44.300
That's dysplasia.

00:07:44.300 --> 00:07:48.145
And then overall, this
lump is a new growth.

00:07:48.145 --> 00:07:49.020
SAL: New growth, neo.

00:07:49.020 --> 00:07:50.478
DOCTOR CONNOLLY:
It's a new plasia,

00:07:50.478 --> 00:07:53.730
and we you reserve it in the
medical field for meaning it's

00:07:53.730 --> 00:07:54.540
growing on its own.

00:07:54.540 --> 00:07:55.915
SAL: And how do
we know it's new?

00:07:55.915 --> 00:07:58.750
Because as you said, it sticks
around like the hyperplasia.

00:07:58.750 --> 00:08:00.820
So how do we know this
wasn't around for a year?

00:08:00.820 --> 00:08:02.361
DOCTOR CONNOLLY:
Oh, it probably was.

00:08:02.361 --> 00:08:04.619
So I think it actually
came from an area here.

00:08:04.619 --> 00:08:06.410
And the thinking would
be that you probably

00:08:06.410 --> 00:08:08.817
had irritants or hyperplasia.

00:08:08.817 --> 00:08:09.900
It would continue to grow.

00:08:09.900 --> 00:08:10.555
Cells divide.

00:08:10.555 --> 00:08:14.000
Cells divide too much, and then
one of them made a mistake.

00:08:14.000 --> 00:08:17.400
And so then it clicked on
something where it would say,

00:08:17.400 --> 00:08:20.550
you know what, from now on I'm
not listening to any clues.

00:08:20.550 --> 00:08:23.110
SAL: And then all of its
descendants were crazy, too.

00:08:23.110 --> 00:08:24.360
DOCTOR CONNOLLY: That's right.

00:08:24.360 --> 00:08:26.447
So then it would then
have a real mean streak,

00:08:26.447 --> 00:08:28.030
and so then they
would grow from here.

00:08:28.030 --> 00:08:29.915
So this is an area
where you can see--

00:08:29.915 --> 00:08:31.623
SAL: I see that pattern
in my own family.

00:08:31.623 --> 00:08:33.190
DOCTOR CONNOLLY: Yeah, exactly.

00:08:33.190 --> 00:08:35.230
So then here, these
are more normal glands.

00:08:35.230 --> 00:08:37.780
But even these,
that's dysplasia.

00:08:37.780 --> 00:08:40.600
So these are growing,
and they do not

00:08:40.600 --> 00:08:42.240
have a good pattern of growth.

00:08:42.240 --> 00:08:45.500
And overall, this
lump is a neoplasia.

00:08:45.500 --> 00:08:46.900
SAL: I see.

00:08:46.900 --> 00:08:49.780
So when we say new, it's kind
of newer than the other tissue.

00:08:49.780 --> 00:08:50.696
DOCTOR CONNOLLY: Yeah.

00:08:50.696 --> 00:08:52.270
We don't really
mean so much the new

00:08:52.270 --> 00:08:57.720
for-- meaning that's new
as much as its own thing.

00:08:57.720 --> 00:08:59.040
New kid on the block.

00:08:59.040 --> 00:09:00.220
SAL: OK.

00:09:00.220 --> 00:09:02.860
DOCTOR CONNOLLY: So
this is the neoplasia.

00:09:02.860 --> 00:09:04.570
So this one here is a polyp.

00:09:04.570 --> 00:09:07.980
It has features of
dysplasia, but we

00:09:07.980 --> 00:09:10.780
would say we see no cancer.

00:09:10.780 --> 00:09:12.150
SAL: How would you know that?

00:09:12.150 --> 00:09:13.760
DOCTOR CONNOLLY: And so--

00:09:13.760 --> 00:09:15.210
SAL: Right, because it never
crossed a boundary line.

00:09:15.210 --> 00:09:16.751
DOCTOR CONNOLLY:
And there's a reason

00:09:16.751 --> 00:09:19.490
why the boundary is important,
is that if you look here,

00:09:19.490 --> 00:09:22.970
these are all the surface cells.

00:09:22.970 --> 00:09:25.610
Down here, these
are the vessels that

00:09:25.610 --> 00:09:27.090
go to the rest of the body.

00:09:27.090 --> 00:09:28.690
These are blood vessels.

00:09:28.690 --> 00:09:30.071
These ones are
called lymphatics,

00:09:30.071 --> 00:09:31.570
and what lymphatics
are is they just

00:09:31.570 --> 00:09:34.180
take the clear
fluid around there.

00:09:34.180 --> 00:09:39.190
SAL: So these right here are
the lymphatics, the clear fluid.

00:09:39.190 --> 00:09:41.240
Fluid can go back and
forth between blood vessels

00:09:41.240 --> 00:09:42.710
and the lymph system?

00:09:42.710 --> 00:09:43.626
DOCTOR CONNOLLY: Yeah.

00:09:43.626 --> 00:09:45.760
Usually what happens
is that blood comes

00:09:45.760 --> 00:09:49.050
in an artery like this, goes on
down to these little vessels.

00:09:49.050 --> 00:09:51.470
And then a little bit
of the clear parts of it

00:09:51.470 --> 00:09:53.150
will kind of leak out into it.

00:09:53.150 --> 00:09:55.441
SAL: The red blood cells are
too big, kind of leak out.

00:09:55.441 --> 00:09:56.380
DOCTOR CONNOLLY: Yeah.

00:09:56.380 --> 00:09:58.555
So then the lymph is the
clear stuff that comes out.

00:09:58.555 --> 00:09:59.930
And then this is
how it gets back

00:09:59.930 --> 00:10:02.180
to the rest of your body are
through these lymphatics,

00:10:02.180 --> 00:10:05.920
so you can see you do not
want neoplastic cells in the--

00:10:05.920 --> 00:10:07.729
SAL: Right, because
once they're in there,

00:10:07.729 --> 00:10:09.270
they can get to any
part of the body.

00:10:09.270 --> 00:10:09.680
DOCTOR CONNOLLY: Go anyplace.

00:10:09.680 --> 00:10:10.240
And then guess what.

00:10:10.240 --> 00:10:10.824
Set up shop.

00:10:10.824 --> 00:10:11.740
New kids on the block.

00:10:11.740 --> 00:10:12.810
They just do what they want.

00:10:12.810 --> 00:10:13.560
SAL: Mis-mis-stas.

00:10:13.560 --> 00:10:14.514
I can't say the word.

00:10:14.514 --> 00:10:15.680
DOCTOR CONNOLLY: Metastasis.

00:10:15.680 --> 00:10:19.210
So metastasis would be if
it gets into these things,

00:10:19.210 --> 00:10:21.085
it can get out of
the colon in a hurry.

00:10:21.085 --> 00:10:22.585
SAL: Go anywhere
in the body, right.

00:10:22.585 --> 00:10:25.860
DOCTOR CONNOLLY: So this is
one where it is not cancer,

00:10:25.860 --> 00:10:27.520
and it has not
invaded these areas

00:10:27.520 --> 00:10:29.160
where it gets the
rest of the body.

00:10:29.160 --> 00:10:30.710
SAL: Fascinating.


Normal colon tissue

WEBVTT
Kind: captions
Language: en

00:00:01.184 --> 00:00:05.642
This is Sal here and I'm at Stanford Medical School with Dr. Andy Connelly.

00:00:05.642 --> 00:00:10.240
Hi there Sal, I'm here to discuss with you histology today.

00:00:10.240 --> 00:00:14.745
Histology! And, and forgive me, for what is probably a simple question, but what is histology?

00:00:14.745 --> 00:00:20.178
So it will be the -ology, the study of, in this case the histo-, means tissues.

00:00:20.178 --> 00:00:28.800
We're going to be looking up the cellular components of organs.

00:00:28.800 --> 00:00:29.300
Cool... yeah.

00:00:29.300 --> 00:00:32.578
So what we're going to be looking at today is the histology of the colon.

00:00:32.578 --> 00:00:39.683
And so for the colon we often have colon specimens coming in from pathology.

00:00:39.683 --> 00:00:45.813
And so the colon, like you were saying before, is the large intestine.

00:00:45.813 --> 00:00:53.150
So if you have this piece of large intestine, and its removed from the patient because there is an area

00:00:53.150 --> 00:00:54.451
of cancer.

00:00:54.451 --> 00:01:01.324
It might be cancer, they're actually pretty good now about doing colonoscopy.

00:01:01.324 --> 00:01:03.460
Looking from the inside--

00:01:03.460 --> 00:01:09.637
They'll often have looked inside think it looks like cancer

00:01:09.637 --> 00:01:12.795
take a little piece and send it to us before hand, and then they remove it.

00:01:12.795 --> 00:01:15.488
And the reason why they want to send it to you is

00:01:15.488 --> 00:01:18.089
even if they know its cancer how severe is this cancer?

00:01:18.089 --> 00:01:22.686
How severe is the cancer? They also want to get a really good tissue diagnosis

00:01:22.686 --> 00:01:28.027
to make sure if they're going to go remove a piece of your colon, that they really know that its cancer

00:01:28.027 --> 00:01:30.349
rather than it just looks like cancer.

00:01:30.349 --> 00:01:32.485
So its the definitive proof before they remove it.

00:01:32.485 --> 00:01:38.011
So then if this is the cancer that's removed they clearly want to be able to check the margins

00:01:38.011 --> 00:01:41.773
to make sure its removed in its entirety.

00:01:41.773 --> 00:01:46.417
But often inside of there, they'll find other pieces of tissues, like here's a polyp

00:01:46.417 --> 00:01:50.597
And when we say check the margins, this is literally, just making sure

00:01:50.597 --> 00:01:53.197
you've covered enough material so that you've gotten all the cancer in it

00:01:53.197 --> 00:01:56.030
that you're not kind of cutting through the cancer and that you've missed something.

00:01:56.030 --> 00:01:58.445
That's right, because this is actually one of the traditional

00:01:58.445 --> 00:02:01.464
surgical cures of cut it out to cure.

00:02:01.464 --> 00:02:04.296
Colon cancer, that tends to still be the case.

00:02:04.296 --> 00:02:07.036
Because you cut it out to make sure you cure it.

00:02:07.036 --> 00:02:09.916
There are many other kinds of cancers that which spread so widely early on

00:02:09.916 --> 00:02:12.238
that you don't usually cut out.

00:02:12.238 --> 00:02:17.625
So then the polyp can be found in a piece of colon removed

00:02:17.625 --> 00:02:20.458
a polyp is something that just sticks up.

00:02:20.458 --> 00:02:23.940
Any tissue that sticks up. It's not necessarily cancer.

00:02:23.940 --> 00:02:28.677
No, so for instance another common place you hear about is

00:02:28.677 --> 00:02:30.953
some people in the sinuses might have sinus trouble

00:02:30.953 --> 00:02:32.903
and they'll have a sinus polyp

00:02:32.903 --> 00:02:34.947
those are almost always just inflamed.

00:02:34.947 --> 00:02:40.705
And then we'll find areas in which it's just the lining

00:02:40.705 --> 00:02:43.167
that's been roughened, and we'll take sections of those.

00:02:43.167 --> 00:02:46.835
And that can happen from just someone being allergic to food

00:02:46.835 --> 00:02:48.832
Yeah, irritations of such.

00:02:48.832 --> 00:02:51.108
Yes, irritations of certain sites.

00:02:51.108 --> 00:02:54.544
So we're going to have the areas where its kind of irritated

00:02:54.544 --> 00:02:56.774
some in which there's a polyp sticking out

00:02:56.774 --> 00:02:59.328
and we'll look at it under a microscope

00:02:59.328 --> 00:03:02.439
and then that's the thing that we're mainly worried about

00:03:02.439 --> 00:03:06.479
So that's what we're going to cover in the slides

00:03:06.479 --> 00:03:08.616
that we look at today.

00:03:08.616 --> 00:03:11.170
So this first one we're looking at is an example of

00:03:11.170 --> 00:03:12.842
a normal margin

00:03:12.842 --> 00:03:14.792
And so it's from a little piece

00:03:14.792 --> 00:03:16.139
from the edge

00:03:16.139 --> 00:03:18.832
So they actually call the tissue margin?

00:03:18.832 --> 00:03:20.040
Yeah, tissue margin

00:03:20.040 --> 00:03:21.805
Normal tissue.

00:03:21.805 --> 00:03:25.613
So this is the edge of the specimen, and [the surgeons will] say, "Is the margin clear?"

00:03:25.613 --> 00:03:29.049
Dr: In this case this is an example where the margin IS clear.

00:03:29.049 --> 00:03:30.814
This is normal-looking colon.

00:03:30.814 --> 00:03:34.808
S: This is a cross-section, crossing the boundary of the colon,

00:03:34.808 --> 00:03:43.306
this area at the top right here, would be the inside of the colon, where the poop is...

00:03:43.306 --> 00:03:51.665
Dr: Doctors say stool. That's the stool in the middle, and the supportive tissue is underneath.

00:03:51.665 --> 00:03:53.941
S: Part of the structural tissue of the tube?

00:03:53.941 --> 00:03:59.328
Dr: Right. Now let's drive around the slide.

00:03:59.328 --> 00:04:04.622
This is a virtual slide where we took the typical glass microscope slide, and put it in a special

00:04:04.622 --> 00:04:09.452
machine which took lots and lots of photographs at high power, then stitched them all together

00:04:09.452 --> 00:04:13.214
as one massive image. So that allows you to zoom in and look around.

00:04:13.214 --> 00:04:16.511
S: To let me get my own bearings, this polyp...

00:04:16.511 --> 00:04:20.690
Dr: No, this is just regular tissue--a little bit of a fold, not a polyp.

00:04:20.690 --> 00:04:25.102
S: So how large is this, about a centimeter?

00:04:25.102 --> 00:04:31.464
Dr: About like that. If I had to guess, about 5-6mm.

00:04:31.464 --> 00:04:43.167
So, now to drive around, these are the controls for zooming in and out.

00:04:43.167 --> 00:04:55.288
So I can look at something more closely, and this is the mucosa.

00:04:55.288 --> 00:04:57.935
S: Mucosa. Sounds very similar to mucus.

00:04:57.935 --> 00:05:03.369
Dr: Right. The mucosa is the lining that makes the mucus, it's the slimy part.

00:05:03.369 --> 00:05:07.270
S: This white stuff up here?

00:05:07.270 --> 00:05:16.418
Dr: This suff is the slimy mucus. So, it keeps the insides from drying out--

00:05:16.418 --> 00:05:21.666
because it's a very hydrated gel. It also means that things can glide along without

00:05:21.666 --> 00:05:25.613
abrading the surface. When you look at it, it has architecture in which

00:05:25.613 --> 00:05:36.016
these glands, they're like test-tubes sticking down, and the purpose is to increase the surface area.

00:05:36.016 --> 00:05:42.285
S: And the term gland, is any structure containing fluid and releases the fluid?

00:05:42.285 --> 00:05:49.066
Dr: A gland is an epithelial structure, so it's made of cells that are packed tightly,

00:05:49.066 --> 00:05:54.220
and the cells have a top and a bottom, and they're formed into some sort of enfolding

00:05:54.220 --> 00:05:57.285
or structure, so that there is a middle and an outside.

00:05:57.285 --> 00:06:04.112
S: When we say something is epithelial, it's the stuff facing the outside world?

00:06:04.112 --> 00:06:09.824
Dr: Yes. The epithelium is a special class of cells in which they are facing the outside world,

00:06:09.824 --> 00:06:13.168
again, tightly packed, and there's a top and a bottom.

00:06:13.168 --> 00:06:19.437
S: And even though to a layperson this area right here does not seem like the outside world,

00:06:19.437 --> 00:06:21.806
it seems like it's inside of you, we're kind of like big donuts.

00:06:21.806 --> 00:06:27.239
Dr: That's right. And the colonoscopist proves that it's connected to the outside world.

00:06:27.239 --> 00:06:29.793
S: MUAHAHA!! I guess they do prove that! XD

00:06:29.793 --> 00:06:40.428
Dr: So that's still the outside world. This is the architecture where you have enfoldings to increase

00:06:40.428 --> 00:06:42.843
the surface area. And it's creating this mucus.

00:06:42.843 --> 00:06:50.831
Let me look at the highest power. Look at these cells! When we look at these cells,

00:06:50.831 --> 00:06:56.914
there are two main types of cells. There's this one here, which is the goblet cell.

00:06:56.914 --> 00:07:05.691
S: Goblet cell. It's not just this white part, it goes all the way down there?

00:07:05.691 --> 00:07:13.075
Dr: Yeah...let me have that pen! It has a top like that, and you see this wine glass?

00:07:13.075 --> 00:07:20.366
S: It's literally shaped like a goblet! I was circling the wrong handle.

00:07:20.366 --> 00:07:23.524
Dr: That nucleus belonged to some other cell.

00:07:23.524 --> 00:07:32.627
What's next to it is these thin cells here, which do not have all the mucus inside of them.

00:07:32.627 --> 00:07:35.367
These guys are the tall ones.

00:07:35.367 --> 00:07:39.685
S: Where you see only the nucleus? The white part is just the mucus inside the cell.

00:07:39.685 --> 00:07:52.781
Dr: Yes. Mucus is the term for either the overall structure or the material that is elaborated up here,

00:07:52.781 --> 00:07:59.608
chemically it is called mucin, and mucin is almost like that goo runners eat,

00:07:59.608 --> 00:08:02.813
it is just a lot of sugar holding a lot of water.

00:08:02.813 --> 00:08:08.014
S: I see. I guess it would be bad branding to call it Mucus-In-A-Bag. MUAHAHA!! >:-}

00:08:08.014 --> 00:08:13.354
Dr: Exactly! So they stick with "goo". But this one has a lot of sugar, takes in lots of water,

00:08:13.354 --> 00:08:16.419
that is released and it forms this surface here.

00:08:16.419 --> 00:08:19.159
S: To let stuff flow by.

00:08:19.159 --> 00:08:23.246
Dr: What the other cell does is the other main thing in addition to letting things flow through,

00:08:23.246 --> 00:08:29.144
is to absorb water. So the idea is you do not want to release the 2L of fluid you have

00:08:29.144 --> 00:08:32.766
around every one of your meals. You want to get a lot of that back.

00:08:32.766 --> 00:08:35.042
S: That's one of the main functions of the large intestine?

00:08:35.042 --> 00:08:38.618
Dr: It is. It is a consolidation process to the stool. So you're going to absorb a lot of water

00:08:38.618 --> 00:08:44.423
and doing it through these cells.

00:08:44.423 --> 00:08:54.686
S: The mucin comes out here, and the water absorbed by parts without mucin, so right there.

00:08:54.686 --> 00:09:02.256
Dr: Yupperz. That's right. The two main functions of the colon are right there with those two cells.

00:09:02.256 --> 00:09:13.494
S: To get a perspective of where we are, the whole thing is about .5cm, what's our scale here?

00:09:13.494 --> 00:09:26.776
Dr: Our favorite scale-bar here is to look for blood vessels, for red blood cells,

00:09:26.776 --> 00:09:30.120
One right there, is 7micro- m in diameter.

00:09:30.120 --> 00:09:36.296
S: 7micro-m. A micrometer is a millionth of a meter, or 1/1000th of 1mm.

00:09:36.296 --> 00:09:41.219
Dr: That's right. Let's round off to 1/100th of 1mm.

00:09:41.219 --> 00:09:47.024
S: You put 100 of these next to each other you get 1mm. So 1mm would be bigger than our entire screen.

00:09:47.024 --> 00:09:54.826
Dr: Right. You see with these glands, 1mm would be this span, which we're saying is about like that,

00:09:54.826 --> 00:09:57.240
That's why from here to here it might be about 7mm.

00:09:57.240 --> 00:10:03.928
Dr: RBCs are found in just about every microscopic field, and they're always 7micro-m.

00:10:03.928 --> 00:10:16.513
When looking here, this is very well formed. You can see these tubular glands,

00:10:16.513 --> 00:10:20.646
just a hint over here, because they are like test-tubes, sometimes they're not going straight up and

00:10:20.646 --> 00:10:22.690
down, sometimes they look a little on an angle...

00:10:22.690 --> 00:10:28.262
S: They actually are reaching the surface, we just don't see it based on the way it's cut?

00:10:28.262 --> 00:10:34.764
So this one right here, it was cut at an angle, so it looks embedded there in 2D,

00:10:34.764 --> 00:10:37.318
but in 3D we would see a full tube.

00:10:37.318 --> 00:10:43.820
Dr: Just to go back to the microscopy, we're seeing this because it's only 4microns thick,

00:10:43.820 --> 00:10:48.185
and we're sending light through this tissue.

00:10:48.185 --> 00:10:53.293
So that's why you can get a cross-section that doesn't show you 3D. Very much 2D.

00:10:53.293 --> 00:11:03.928
S: Cool! So this is what a healthy margin tissue would look like?

00:11:03.928 --> 00:11:08.340
Dr: Yes, this is a healthy colon, so you would thankfully say on the proximal margin,

00:11:08.340 --> 00:11:13.727
which is up more towards the mouth, that's clear. You take another section like this from the distal

00:11:13.727 --> 00:11:17.999
margin, more towards the end, and you say that's clear, so that means they removed the cancer.

00:11:17.999 --> 00:11:20.786
S: When you say proximal margin is close to the mouth,

00:11:20.786 --> 00:11:27.241
you're saying the mouth of that cut of the tube, not mouth of the person.

00:11:27.241 --> 99:59:59.999
Dr: That's right. So the proximal and distal margins are clear, if they look like this.


Hyperplasia in colon tissue

WEBVTT
Kind: captions
Language: en

00:00:00.066 --> 00:00:01.190
SAL KHAN: This is Sal here.

00:00:01.190 --> 00:00:02.606
And I'm at Stanford
Medical School

00:00:02.606 --> 00:00:05.160
with Dr. Andy Connolly,
who's a pathologist here.

00:00:05.160 --> 00:00:07.040
And this is the
second in our series

00:00:07.040 --> 00:00:08.683
on looking at some
of these slides.

00:00:08.683 --> 00:00:09.516
ANDY CONNOLLY: Yeah.

00:00:09.516 --> 00:00:12.780
So we left off last time,
Sal, looking at this piece

00:00:12.780 --> 00:00:15.660
here, which is normal colon.

00:00:15.660 --> 00:00:17.730
We had said this is an
example of what you'd

00:00:17.730 --> 00:00:21.006
see at the edge of a specimen
released for colon cancer.

00:00:21.006 --> 00:00:22.880
Now I'm going to click
to the next one, which

00:00:22.880 --> 00:00:25.856
is a slightly more
worrisome area if you're

00:00:25.856 --> 00:00:27.880
a pathologist looking
through the colon.

00:00:27.880 --> 00:00:32.070
And so I'm going to zoom
in just a little bit here

00:00:32.070 --> 00:00:33.070
to take a look at these.

00:00:33.070 --> 00:00:35.582
SAL KHAN: Looks very worrisome
compared to the last one.

00:00:35.582 --> 00:00:37.040
ANDY CONNOLLY: And
so what we don't

00:00:37.040 --> 00:00:39.340
like about it is
we saw before this

00:00:39.340 --> 00:00:41.470
is what the normal
gland looks like.

00:00:41.470 --> 00:00:44.020
It's a test tube
shape and down, and it

00:00:44.020 --> 00:00:45.750
has these cells
which are normal.

00:00:45.750 --> 00:00:48.480
Now all of a sudden it
looks a little thicker here,

00:00:48.480 --> 00:00:51.070
and what catches our eye
also is these aren't just

00:00:51.070 --> 00:00:53.300
straight test tubes anymore.

00:00:53.300 --> 00:00:54.800
They divide.

00:00:54.800 --> 00:00:57.160
They kind of go in
and out like that.

00:00:57.160 --> 00:00:59.250
SAL KHAN: But they
still are test tubes.

00:00:59.250 --> 00:01:00.530
Following up what we
said in the last video

00:01:00.530 --> 00:01:02.460
is that they just look
like circles as opposed

00:01:02.460 --> 00:01:04.239
to test tubes because we're
taking a cross-section,

00:01:04.239 --> 00:01:06.430
because they're kind of popping
out of the two dimensions.

00:01:06.430 --> 00:01:06.770
ANDY CONNOLLY: That's right.

00:01:06.770 --> 00:01:08.970
But although, when you
come from the surface here

00:01:08.970 --> 00:01:11.234
and you go down, they
normally should never branch.

00:01:11.234 --> 00:01:11.900
SAL KHAN: I see.

00:01:11.900 --> 00:01:13.858
ANDY CONNOLLY: And so
these ones are branching,

00:01:13.858 --> 00:01:14.860
and that's always bad.

00:01:14.860 --> 00:01:17.446
And then you can
see the way-- when

00:01:17.446 --> 00:01:19.070
you're putting a
cross-section, there's

00:01:19.070 --> 00:01:21.830
normally just a little
hole in the middle.

00:01:21.830 --> 00:01:23.830
And that's where the
mucin-- you can even see it

00:01:23.830 --> 00:01:24.754
spilling out there.

00:01:24.754 --> 00:01:25.337
SAL KHAN: Wow.

00:01:25.337 --> 00:01:26.020
You can.

00:01:26.020 --> 00:01:27.270
ANDY CONNOLLY: So you
can see it just kind

00:01:27.270 --> 00:01:28.610
of coming right out of there.

00:01:28.610 --> 00:01:31.040
This one here looks different.

00:01:31.040 --> 00:01:32.880
And what it is, it's piled up.

00:01:32.880 --> 00:01:35.790
And so it's a little
bit bigger around.

00:01:35.790 --> 00:01:38.690
And in order for these
cells, more cells--

00:01:38.690 --> 00:01:41.350
they're going to be all
piled up and going like this,

00:01:41.350 --> 00:01:42.680
and they even branch.

00:01:42.680 --> 00:01:44.400
And so what this
is, is that we look

00:01:44.400 --> 00:01:46.140
a little more closely
at this piece.

00:01:46.140 --> 00:01:48.820
And we say, hmm, I
wonder if that's cancer.

00:01:48.820 --> 00:01:50.500
Could it be pre-cancer,
or is this just

00:01:50.500 --> 00:01:52.230
an area of irritation?

00:01:52.230 --> 00:01:56.070
And a common response of
the body to irritation

00:01:56.070 --> 00:01:58.940
is some sort of change.

00:01:58.940 --> 00:02:01.772
And like we were saying before,
epithelium is the top layer.

00:02:01.772 --> 00:02:02.730
SAL KHAN: Right, right.

00:02:02.730 --> 00:02:04.150
The stuff that's facing
the outside world.

00:02:04.150 --> 00:02:04.990
ANDY CONNOLLY: Facing
the outside world.

00:02:04.990 --> 00:02:07.281
So if it's irritated, often
the epithelium will change.

00:02:07.281 --> 00:02:10.404
And in this case, it's changing
by undergoing more growth.

00:02:10.404 --> 00:02:12.570
SAL KHAN: Is it always--
even if it's non-cancerous,

00:02:12.570 --> 00:02:14.574
is it going to be a higher
likelihood that it's

00:02:14.574 --> 00:02:16.240
going to become
cancerous in the future?

00:02:16.240 --> 00:02:18.073
ANDY CONNOLLY: A lot
of cancers, it appears,

00:02:18.073 --> 00:02:21.870
in the body come from parts
of the body that are either

00:02:21.870 --> 00:02:24.755
irritated or have some sort
of environmental challenges

00:02:24.755 --> 00:02:26.792
that are constantly at them.

00:02:26.792 --> 00:02:29.250
And part of that is because
there's a lot of cell division.

00:02:29.250 --> 00:02:29.560
SAL KHAN: I see.

00:02:29.560 --> 00:02:31.351
ANDY CONNOLLY: If you
keep dividing a cell,

00:02:31.351 --> 00:02:33.190
you might have
errors in the DNA.

00:02:33.190 --> 00:02:35.514
SAL KHAN: So that's why
skin cells, bowel cells--

00:02:35.514 --> 00:02:36.680
ANDY CONNOLLY: That's right.

00:02:36.680 --> 00:02:37.804
And even things like liver.

00:02:37.804 --> 00:02:39.400
If you keep damaging
your liver, you

00:02:39.400 --> 00:02:42.080
might have ongoing
things and liver cancer.

00:02:42.080 --> 00:02:45.150
So when you're looking
here, the pathologist

00:02:45.150 --> 00:02:46.980
would look at this area
and say, well, it's

00:02:46.980 --> 00:02:50.880
a dividing gland that's kind
of thrown up in these areas.

00:02:50.880 --> 00:02:53.480
But largely, they're
still making mucin

00:02:53.480 --> 00:02:56.350
or they're this type here,
which looks like it's tall

00:02:56.350 --> 00:02:57.634
and probably absorbing water.

00:02:57.634 --> 00:02:58.300
SAL KHAN: I see.

00:02:58.300 --> 00:03:00.840
So even within these
test tubes-- well,

00:03:00.840 --> 00:03:02.090
they're not really test tubes.

00:03:02.090 --> 00:03:03.700
But inside of these
vessels, there

00:03:03.700 --> 00:03:06.394
are also still the
absorptive cells as well.

00:03:06.394 --> 00:03:07.560
ANDY CONNOLLY: That's right.

00:03:07.560 --> 00:03:11.694
So here, we would sign
this off as hyperplasia.

00:03:11.694 --> 00:03:12.610
SAL KHAN: Hyperplasia.

00:03:12.610 --> 00:03:14.280
So hyper, like too
much of something.

00:03:14.280 --> 00:03:14.620
ANDY CONNOLLY: Yes.

00:03:14.620 --> 00:03:15.670
SAL KHAN: And plasia?

00:03:15.670 --> 00:03:16.590
ANDY CONNOLLY: Growth.

00:03:16.590 --> 00:03:16.800
SAL KHAN: See.

00:03:16.800 --> 00:03:18.758
ANDY CONNOLLY: And so
plasia just means growth.

00:03:18.758 --> 00:03:21.420
And so hyperplasia
means too much growth.

00:03:21.420 --> 00:03:24.320
But the important thing is if
you took away the irritant,

00:03:24.320 --> 00:03:25.644
it wouldn't do this.

00:03:25.644 --> 00:03:26.310
SAL KHAN: I see.

00:03:26.310 --> 00:03:27.180
ANDY CONNOLLY: So
if you took away

00:03:27.180 --> 00:03:29.600
whatever the irritant
is for the hyperplasia,

00:03:29.600 --> 00:03:31.254
it would go back
to being normal.

00:03:31.254 --> 00:03:31.920
SAL KHAN: I see.

00:03:31.920 --> 00:03:32.280
I see.

00:03:32.280 --> 00:03:33.170
And that's just
something we know.

00:03:33.170 --> 00:03:33.730
ANDY CONNOLLY: That's right.

00:03:33.730 --> 00:03:35.229
SAL KHAN: There's
some stimulus that

00:03:35.229 --> 00:03:37.234
was causing these
cells to do that.

00:03:37.234 --> 00:03:39.525
It might have been diet,
might have been some chemical.

00:03:39.525 --> 00:03:41.040
It could have been just--

00:03:41.040 --> 00:03:41.730
ANDY CONNOLLY: We're
never really sure

00:03:41.730 --> 00:03:43.271
what, because so
much of it is things

00:03:43.271 --> 00:03:45.280
that just float on through.

00:03:45.280 --> 00:03:46.740
So it's really hard to know.

00:03:46.740 --> 00:03:49.635
But, yeah, this is probably
too much growth in response

00:03:49.635 --> 00:03:50.260
to an irritant.

00:03:50.260 --> 00:03:52.630
SAL KHAN: So it's
possible that it just

00:03:52.630 --> 00:03:55.900
happened to be when this section
of the colon was taken out.

00:03:55.900 --> 00:03:57.720
If this was done
a day later maybe,

00:03:57.720 --> 00:03:58.930
then maybe this might
have not been there?

00:03:58.930 --> 00:04:01.096
ANDY CONNOLLY: Yeah, probably
take longer than that.

00:04:01.096 --> 00:04:02.290
A couple weeks.

00:04:02.290 --> 00:04:02.980
SAL KHAN: A couple
weeks, but it's--

00:04:02.980 --> 00:04:03.540
ANDY CONNOLLY:
Because what happens

00:04:03.540 --> 00:04:05.370
is that the cells
come from the bottom,

00:04:05.370 --> 00:04:07.790
and they work their
way up towards the top.

00:04:07.790 --> 00:04:09.960
And so eventually the
top would behave--

00:04:09.960 --> 00:04:10.955
SAL KHAN: And so the way
the body works here--

00:04:10.955 --> 00:04:13.330
and it's kind of like the
skin-- is this as constant.

00:04:13.330 --> 00:04:15.204
These cells are being
used up, because things

00:04:15.204 --> 00:04:16.700
are kind of scraping by them.

00:04:16.700 --> 00:04:18.001
And they get a lot of use.

00:04:18.001 --> 00:04:18.959
ANDY CONNOLLY: They do.

00:04:18.959 --> 00:04:22.250
And in fact, there's a lot
known now about stem cells.

00:04:22.250 --> 00:04:25.121
And the stem cells for the
intestine are these guys.

00:04:25.121 --> 00:04:25.870
SAL KHAN: Oh, wow.

00:04:25.870 --> 00:04:28.915
So how do you differentiate
the stem cell versus--

00:04:28.915 --> 00:04:31.290
ANDY CONNOLLY: At the very
bottom, the bottom hemisphere,

00:04:31.290 --> 00:04:32.742
there are going
to be cells there

00:04:32.742 --> 00:04:34.200
that do not have
the open chromatin

00:04:34.200 --> 00:04:35.474
and kind of elongated.

00:04:35.474 --> 00:04:36.140
SAL KHAN: I see.

00:04:36.140 --> 00:04:37.723
ANDY CONNOLLY: There
may be ones which

00:04:37.723 --> 00:04:40.546
are endocrine cells, meaning
they release hormones.

00:04:40.546 --> 00:04:42.420
And so they may have
hormone-releasing cells.

00:04:42.420 --> 00:04:44.192
But in this bottom
hemisphere, that

00:04:44.192 --> 00:04:46.150
turns out to be where
the intestine keeps them.

00:04:46.150 --> 00:04:47.515
And these guys are
probably the stem cells.

00:04:47.515 --> 00:04:49.180
SAL KHAN: And stem
cells are cells

00:04:49.180 --> 00:04:50.810
that haven't picked
their jobs yet.

00:04:50.810 --> 00:04:52.030
ANDY CONNOLLY: They
haven't, and so there's

00:04:52.030 --> 00:04:53.190
all kinds of stem cells.

00:04:53.190 --> 00:04:57.652
There's the stem cell that
can make a whole body, being.

00:04:57.652 --> 00:04:59.110
But then there's
also the kind that

00:04:59.110 --> 00:05:00.594
can make the rest of the colon.

00:05:00.594 --> 00:05:01.260
SAL KHAN: I see.

00:05:01.260 --> 00:05:03.010
ANDY CONNOLLY: And so
this one is probably

00:05:03.010 --> 00:05:05.400
the stem cell they can make
the rest of the epithelium,

00:05:05.400 --> 00:05:06.650
but these two different kinds.

00:05:06.650 --> 00:05:07.610
SAL KHAN: The two
different types, right.

00:05:07.610 --> 00:05:09.180
ANDY CONNOLLY: So they're
down here at the bottom.

00:05:09.180 --> 00:05:10.880
That's about where
you'd want them.

00:05:10.880 --> 00:05:11.090
SAL KHAN: Exactly.

00:05:11.090 --> 00:05:11.590
Right.

00:05:11.590 --> 00:05:12.670
ANDY CONNOLLY: So
that makes sense.

00:05:12.670 --> 00:05:15.090
So down there are your stem
cells, and it grows like that.

00:05:15.090 --> 00:05:16.650
So this is a hyperplasia.

00:05:16.650 --> 00:05:20.260
So I'd like to show you
next the next step, which

00:05:20.260 --> 00:05:21.220
is a pre-cancer legion.

00:05:21.220 --> 00:05:22.650
Should we do that
in another videos?

00:05:22.650 --> 00:05:22.700
SAL KHAN: Yeah.

00:05:22.700 --> 00:05:24.500
Let's do that in another video.


Correlation and causality

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Language: en

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I have this article
right here from WebMD.

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And the point of this isn't
to poke holes at WebMD.

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I think they have
some great articles

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and they have some great
information on their site.

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But what I want to
do here is to think

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about what a lot of
articles you might read

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or a lot of research you
might read are implying

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and to think about
whether they really

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imply what they
claim to be implying.

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So this is an excerpt
of an article,

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and the title of the article
says "Eating breakfast

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may beat teen obesity."

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So they're already
trying to create

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this cause-and-effect
relationship.

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The title itself says if
you eat breakfast then

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you're less likely--
or you won't be obese.

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You're not going to be obese.

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So the title right there
already sets up this.

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That eating breakfast
may beat teen obesity.

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And then they tell
us about the study.

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"In the study,
published in Pediatrics,

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researchers analyzed the
dietary and weight patterns

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of a group of 2,216 adolescents
over a five-year period

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from public schools in
Minneapolis-Saint Paul,

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Minnesota."

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And I won't talk
too much about this.

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It looks like a
good sample size.

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It was over a large
period of time.

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I'll just give the researchers
the benefit of the doubt,

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assume that it was
over broad audience,

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that they were able to control
for a lot of variables.

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But then they go on to
say, "The researchers write

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that teens who ate
breakfast regularly

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had a lower percentage of total
calories from saturated fat

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and ate more fiber
and carbohydrates."

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And to some degree that
first-- "than those

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who skipped breakfast."

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And to some degree this
first sentence is obvious.

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Breakfast tends to be
things like cereals, grains.

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You eat syrup, you
eat waffles-- that all

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tends to fall in the category
of carbohydrates and sugars.

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And frankly, that's not even
necessarily a good thing.

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Not obvious to me
whether bacon is

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more or less healthy than
downing a bunch of syrup

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or Fruit Loops or whatever else.

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But we'll let that
be right here.

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"In addition, regular
breakfast eaters

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seemed more
physically active then

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the breakfast skippers."

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So over here they're
once again trying

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to create this other
cause-and-effect relationship.

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Regular breakfast eaters
seemed more physically active

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than the breakfast skippers.

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So the implication
here is that breakfast

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makes you more active.

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And then this last
sentence right over here,

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they say "Over time,
researchers found

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teens who regularly
ate breakfast

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tended to gain less weight and
had a lower body mass index

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than breakfast skippers."

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So you could--
they're telling us

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that breakfast skipping--
this is the implication here--

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is more likely, or it can be a
cause of making you overweight

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or maybe even making you obese.

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So the entire narrative here,
from the title all the way

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through every
paragraph, is look,

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breakfast prevents obesity.

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Breakfast makes you active.

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Breakfast skipping
will make you obese.

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So you just say then, boy,
I have to eat breakfast.

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And you should always
think about the motivations

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and the industries around
things like breakfast.

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But the more
interesting question

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is does this research
really tell us

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that eating breakfast
can prevent obesity?

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Does it really tell us
that eating breakfast

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will cause some to
become more active?

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Does it really tell us
that breakfast skipping

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can make you overweight
or make it obese?

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Or, it is more likely,
are they showing

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that these two things
tend to go together?

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And this is a really
important difference.

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And let me kind of state
slightly technical words here.

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And they sound fancy, but
they really aren't that fancy.

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Are they pointing
out causality, which

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is what it seems like
they're implying.

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Eating breakfast causes
you to not be obese.

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Breakfast causes
you to be active.

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Breakfast skipping
causes you to be obese.

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So it looks like they are
kind of implying causality.

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They're implying
cause and effect,

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but really what the study
looked at is correlation.

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The whole point of this is
to understand the difference

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between causality
and correlation

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because they're saying
very different things.

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Causality versus correlation.

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And, as I said, causality
says A causes B. Well,

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correlation just
says A and B tend

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to be observed at the same time.

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Whenever I see B
happening, it looks

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like A is happening
at the same time.

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Whenever A is happening,
it looks like it also

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tends to happen with
B. And the reason

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why it's super
important to notice

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the distinction
between these is you

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can come to very,
very, very, very, very

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different conclusions.

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So the one thing that
this research does do,

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assuming that it
was performed well,

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is it does show a correlation.

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So the study does
show a correlation.

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It does show, if we
believe all of their data,

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that breakfast
skipping correlates

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with obesity and
obesity correlates

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with breakfast skipping.

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We're seeing it
at the same time.

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Activity correlates with
breakfast and breakfast

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correlates with activity--
that all of these correlate.

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What they don't say--
and there's no data here

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that lets me know one way or
the other-- what is causing what

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or maybe you have
some underlying cause

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that is causing both.

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So for example, they're saying
breakfast causes activity,

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or they're implying
breakfast causes activity.

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They're not saying
it explicitly.

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But maybe activity
causes breakfast.

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Maybe.

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They didn't write the study
that people who are active,

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maybe they're more likely
to be hungry in the morning.

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Activity causes breakfast.

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And then you start having
a different takeaway.

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Then you don't say, wait,
maybe if you're active

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and you skip
breakfast-- and I'm not

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telling you that you should.

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I have no data one way
or the other-- maybe

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you'll lose even more weight.

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Maybe it's even a
healthier thing to do.

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We're not sure.

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So they're trying to say,
look, if you have breakfast

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it's going to make
you active, which

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is a very positive outcome.

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But maybe you can have
the positive outcome

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without breakfast.

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Who knows?

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Likewise they say
breakfast skipping,

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or they're implying breakfast
skipping, can cause obesity.

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But maybe it's the
other way around.

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Maybe people who have
high body fat-- maybe,

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for whatever reason, they're
less likely to get hungry

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in the morning.

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So maybe it goes this way.

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Maybe there's a causality there.

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Or even more likely,
maybe there's

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some underlying cause that
causes both of these things

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to happen.

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And you could think of a bunch
of different examples of that.

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One could be the
physical activity.

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And these are all just theories.

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I have no proof for it.

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But I just want to
give you different ways

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of thinking about the same
data and maybe not just coming

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to the same conclusion that
this article seems like it's

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trying to lead us to conclude.

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That we should eat breakfast if
we don't want to become obese.

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So maybe if you're
physically active,

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that leads to you being
hungry in the morning,

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so you're more likely
to eat breakfast.

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And obviously being
physically active

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also makes it so that
you burn calories.

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You have more muscle.

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So that you're not obese.

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So notice if you
view things this way,

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if you say physical activity
is causing both of these,

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then all of a sudden
you lose this connection

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between breakfast and obesity.

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Now you can't make the
claim that somehow breakfast

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is the magic formula for
someone to not be obese.

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So let's say that there
is an obese person-- let's

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say this is the reality, that
physical activity is causing

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both of these things.

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And let's say that there
is an obese person.

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What will you tell them to do?

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Will you tell them, eat
breakfast and you won't

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become obese anymore?

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Well, that might
not work, especially

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if they're not
physically active.

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I mean, what's going
to happen if you

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have an obese person who's
not physically active?

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And then you tell
them to eat breakfast?

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Maybe that'll make things worse.

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And based on that,
that the advice

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or the implication from the
article is the wrong thing.

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Physical activity
maybe is the thing

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that should be focused on.

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Maybe something other
than physical activity.

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Maybe you have sleep,
maybe people who sleep late

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and they're not
getting enough sleep,

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maybe that leads to obesity.

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And obviously, because they're
not getting enough sleep,

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they wake up as late
as possible and they

00:08:06.978 --> 00:08:08.680
have to run to the
next appointment--

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or they have to run to school
in the case of students--

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and maybe that's why
they skip breakfast.

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So once again, if you
find someone that's obese,

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maybe the rule here isn't
to force a breakfast

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down your throat.

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Maybe it will become even
worse because maybe it

00:08:23.519 --> 00:08:26.330
is the lack of sleep that's
causing your metabolism

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to slow down or whatever.

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So it's very, very
important when

00:08:29.342 --> 00:08:31.550
you're looking at any of
these studies to try to say,

00:08:31.550 --> 00:08:34.450
is this a correlation
or is this causality?

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If it's correlation, you cannot
make the judgment that, hey,

00:08:36.951 --> 00:08:39.366
eating breakfast is necessarily
going to make someone less

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obese.

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All that tells you is that
these things move together.

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A better study would be one
that is able to prove causality.

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And then we could think of
other underlying causes that

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would kind of break down the
narrative that this piece is

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trying to say.

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I'm not saying it's wrong.

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Maybe it's absolutely
true that eating breakfast

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will fight obesity.

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But I think it's equally or more
important to think about what

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the other causes
are, not to just make

00:09:03.800 --> 00:09:05.820
a blanket statement like that.

00:09:05.820 --> 00:09:11.030
So for example,
maybe poverty causes

00:09:11.030 --> 00:09:13.540
you to skip breakfast
for multiple reasons.

00:09:13.540 --> 00:09:15.700
Maybe both of your
parents are working.

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There's no one there
to give you breakfast.

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Maybe there's more
stress in the--

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who knows what it might be?

00:09:21.330 --> 00:09:23.264
And so when you
have poverty maybe

00:09:23.264 --> 00:09:25.180
you're more likely to
skip breakfast and maybe

00:09:25.180 --> 00:09:27.040
when there's poverty,
and maybe you

00:09:27.040 --> 00:09:28.717
have two-- both your
parents are working

00:09:28.717 --> 00:09:31.300
and the kids have to make their
own dinner and whatever else--

00:09:31.300 --> 00:09:38.990
maybe they also eat less
healthy at all times of day

00:09:38.990 --> 00:09:41.790
and then that leads to obesity.

00:09:41.790 --> 00:09:43.720
So once again in this
situation, if this

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is the reality of things,
just telling someone

00:09:45.900 --> 00:09:48.820
to also eat breakfast regardless
of what that breakfast is, even

00:09:48.820 --> 00:09:51.050
if it's Fruit Loops
or syrup, that's

00:09:51.050 --> 00:09:54.170
probably not going to
help the situation.

00:09:54.170 --> 00:09:59.130
Maybe it's just eating
unhealthy dinners

00:09:59.130 --> 00:10:00.130
is the underlying cause.

00:10:03.380 --> 00:10:06.897
And if you eat an unhealthy
dinner maybe by breakfast time

00:10:06.897 --> 00:10:08.480
you're not hungry
still because you've

00:10:08.480 --> 00:10:10.180
binged so much on breakfast.

00:10:10.180 --> 00:10:12.490
So you skip breakfast.

00:10:12.490 --> 00:10:15.180
And this also leads to obesity.

00:10:15.180 --> 00:10:18.590
But once again, if this
is the actual reality,

00:10:18.590 --> 00:10:20.480
doing the advice that
that article's saying

00:10:20.480 --> 00:10:21.730
might actually be a bad thing.

00:10:21.730 --> 00:10:24.120
If you need an unhealthy
dinner and then

00:10:24.120 --> 00:10:26.250
force yourself to eat a
breakfast when you're not

00:10:26.250 --> 00:10:28.717
hungry, that might make
the obesity even worse.

00:10:28.717 --> 00:10:30.300
So the whole point
of this video isn't

00:10:30.300 --> 00:10:32.270
to say that the implications
from that article

00:10:32.270 --> 00:10:33.900
are necessarily wrong.

00:10:33.900 --> 00:10:36.980
The important thing is to just
realize that it might be wrong.

00:10:36.980 --> 00:10:39.580
And that just because you saw
this correlation with the data,

00:10:39.580 --> 00:10:41.960
it doesn't mean that
eating breakfast is going

00:10:41.960 --> 00:10:45.000
to somehow magically
fight obesity.