walk-through of ileum model, focusing on key anatomy of small intestine and identifying the 4 tunics.
so i have a model of the small intestine
here
we're looking specifically at the ileum
and so
starting here you've got the mucosa
you've got the submucosa complete with
our
Peyer's patches, we have a
rich blood supply here you have
lymphatic vessels and glands
um traveling elsewhere in the small
intestine so again
mucosa submucosa
this is the muscularis externa um
these two layers here so this is the
circular layer
this is the longitudinal layer and then
the most
superficial of these is going to be the
serosa
down here which is what you're which
using connective tissue and remember
that's going to wrap around
the ileum as as well as the rest of the
small intestine to form the mesentery or
that double layer serosa
coming into some more specifics up here
i'm going to zoom in on one of these
villi
and what you're seeing this is called
the lacteal these are the lymphatic
they're really specialized lymphatic
vessels
that dive up into these villi
and this is where chylomicrons
so digested triglycerides
are going to be absorbed because they're
non-polar in nature
it would be difficult for them to enter
at the capillaries where you
predominantly have water
in addition the you'll find that the
lymphatic vessels are going to be more
permeable than the capillaries so those
large chylomicrons rather than being
absorbed
from the lumen of our GI tract into our
body through the capillaries again those
chylomicrons are instead going to be
absorbed into these
lacteals take it up into the
lymphatic system
from there in addition
these blue dots are showing goblet cells
so we know that the intestine is able to
secrete mucus and that's where that will
come from
so these are all the villi coming back
to our submucosal layer i wanted to
address
these Peyer's patches a little bit more
they are an important component of our
immune system
we see that they actually work to to
monitor intestinal
bacterial levels and i think that makes
good sense if you consider that the
ileum is the last component of the small
intestine before we get to
the cecum and the appendix right
actually
so this is the ileum and
this is the cecum and appendix one of
the reasons that a
appendicitis or specifically a rupture
of the appendix can be so
potentially fatal is because that
bacteria
that ruptures from the appendix can
ultimately lead to sepsis
and so if you think about the ilium
being just upstream if you will from the
cecum
and the appendix i think it makes sense
that you would need these specialized
features these Peyer's patches in order to
be able to control
the bacterial population

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