– Now, we are going
to use this nice image of a sagittal section of a human abdomen to talk
about the peritoneal cavity, because the peritoneal
cavity is actually inside the abdominal pelvic
cavity. And there are two– maybe we can just
call it one serous membrane that is associated
with peritoneal cavity, and it’s the peritoneum. It’s called the peritoneum. And as we know, because we
talked about serous membranes, as we know, serous
membranes have two layers. They have a parietal layer, and remember the parietal
layer lines the cavity itself. So, the parietal peritoneum
lines the peritoneal cavity. And then, what was the name of
the part of the serous membrane that actually covers the organs? It covers the guts,
covers the viscera, that’s the visceral peritoneum. So you have
the parietal peritoneum and the visceral peritoneum. Okay.
Push pause. Take a look
at this sagittal section through the abdominal
pelvic cavity and tell me
what color is representing the parietal peritoneum.
Go ahead. We know it’s lining
the whole cavity. Look.
There it is. It’s orange.
Look at this orange membrane that is lining
the whole flipping cavity. It’s going to come out,
eventually. Now, look at this.
This is interesting. Is it lining the whole cavity? No. Check out this bad boy. Boy, whatever.
Whoever that is. That is not contained.
Look. There is a section
of the abdominal pelvic cavity that didn’t get lined
by parietal peritoneum. Everywhere else did get lined
by the parietal peritoneum. Look. Here’s another piece
that did not get lined. How interesting is that?
That’s actually the pancreas. Guess who this is?
That’s the duodenum. The duodenum is not– it’s actually
outside the peritoneal cavity. And you can look
at this and you can be like, oh, yeah.
It totally is. Now, the parietal peritoneum is
lining the cavity. We’re cool.
The visceral peritoneum– what’s going
on with the visceral peritoneum? Which one do you think it is?
Look. We can actually see
the part of the membrane that is covering the organs is
the visceral peritoneum. Now, all of this blue,
that’s all visceral peritoneum. Now, I want you
to notice something crazy. Are you ready? Would you agree that this little
piece of visceral peritoneum, which is covering some part
of some digestive tube, is actually– look at this. It’s actually connected
to some other weird structure. These other weird structures are
actually called mesenteries. And mesenteries are sandwiches
of visceral peritoneum. So imagine here is a tube and it’s covered
by visceral peritoneum. And the visceral peritoneum connects on one
side of the tube. But somehow– I mean, how did it even
get there in the first place, and we know it has to connect,
ultimately, to the parietal peritoneum. And so it’s actually completely
surrounding the organ, and then it makes a double
edged sandwich of peritoneum. So the mesenteries contain two
layers of visceral peritoneum. Really?
And guess what’s in there. This is so unbelievable. Nerves, blood vessels are
sandwiched in those little mesenteries.
Here, these are all mesenteries. This is actually
called mesentery proper. It actually forms this really
cool fan that you can visualize. When we get into our cadavers, this fan actually has digestive
tubing on the outer edge of it. And you can imagine
how two serous membranes actually come out
and then scoop around, engulf that digestive
tubing out there. We also have this. This thing right here
is called the greater omentum. The greater omentum. I’m sorry. I think of it as, like,
an apron that’s hanging down. And, again,
all it is is a sandwich of random pieces of serous
membrane of visceral peritoneum that get sandwiched and keep
all of your blood vessels and nerves organized and clean, and it keeps, it hangs down
on the anterior surface, and it attaches– do you know
who this is right here? This is your stomach– ready?
This is really cool. The greater omentum attaches to what part of the stomach,
do you think? To the greater curvature
of the stomach. Seriously?
It’s so nice when it’s easy like that.
Check this out. This puppy is
the lesser omentum. The lesser omentum attaches
to what part of the stomach? This is so dreamy. The lesser curvature
of the stomach. And who does it connect
the stomach to? To the liver.
And again check it out. Here is visceral peritoneum.
It comes out and all it does is form a sandwich
around the stomach. And that little sandwich
of visceral peritoneum which has blood vessels
and nerves and all sorts of important stuff
to keep it from getting tangled and crazy
in the peritoneal cavity– I can’t even remember
what the rest of that sentence was
going to be, but that’s your lesser omentum.
Hum, greater omentum, lesser omentum,
and mesentery proper. Those are the three biggest. We also have the mesocolon,
which is mesentery that’s attached
to the large intestines. We are going to see
that in various places. This is one example
of the mesocolon, because this is
the transverse colon, which is kind of
interesting, also. You did it. You made it through
the digestive system lecture. And I will see you
some day later. Bye-bye.