00:02
So before we get to
the small intestine,
it's important to talk about
the other accessory organs
that are going to be
involved or associate
with the small intestine.
00:14
These include the liver
which is going to have the
function of producing bile,
which is very
important or necessary
for the emulsification of fat.
00:25
The gallbladder which is
going to store the bile
until it is needed for
fat emulsification.
00:33
And also the pancreas.
00:36
The pancreas is very important
because it supplies
most of the enzymes
needed to digest chyme.
00:43
It is also going to
contain bicarbonate
which helps to neutralize
that stomach acid
that's going to be
entering into the duodenum.
00:55
Taking a closer
look at the liver
at the microscopic level.
00:59
We find that the liver is
made up of liver lobules.
01:04
These are hexagonal structures
and functional units
composed of plates of hepatocyte
that are going to filter and
process nutrient-rich blood
that returns to the liver by way
of hepatic portal circulation.
01:21
Each lobule contains
a central vein.
01:24
It is located in its
longitudinal axis.
01:29
At the corner of each lobule
you have what's known
as the portal triad.
01:35
This is going to include a
branch of the hepatic artery,
which is going to supply oxygen
a branch of the
hepatic portal vein,
which is going to bring
nutrient-rich blood
from the intestines,
and a bile duct
which is going to receive
bile from the bile canaliculi.
01:56
Hepatocyte also
have an increased
rough and smooth ER
Golgi apparatus,
peroxisomes,
and mitochondria.
02:06
These help with the
function of the hepatocyte,
which is to produce about 900
milliliters of bile per day.
02:16
The hepatocyte are
also going to be
processing blood-borne
nutrients such as glucose,
which will then be
stored as glycogen
as well as making
plasma proteins.
02:30
The hepatocyte are also
going to be responsible
for the storage of
fat soluble vitamins.
02:36
And also the hepatocytes are
very important in detoxification.
02:42
This includes things like
converting ammonia to urea
when we take in or when we
bring in a lot of amino acids,
but it's also
important for drugs
that we bring into our bodies.
02:55
This is where the
detoxification process
and our bodies are
is going take place.
03:01
Recall that the hepatocyte
of the liver are going
to be responsible
for creating bile.
03:08
Bile is a yellow-green
alkaline solution
that contains bile salts
which are the
cholesterol derivatives
that are going to function
in fat emulsification
and fat absorption in
the small intestines.
03:24
Bile also contains bilirubin,
which is a pigment
that is formed from heme.
03:30
This pigment is broken
down by bacteria
in the intestines to stercobilin
and from here it gives the
feces it's brown color.
03:41
Also found in bile
we have cholesterol,
triglycerides,
phospholipids and
some electrolytes.
03:51
The entero hepatic circulation
is going to involve
as recycling mechanism
that is going to
conserve our bile salts.
04:00
Most of our bile salts
are reabsorbed into
the blood by the ileum,
which is the last part
of the small intestine.
04:08
From there it is
returned to the liver
by way of the
hepatic portal blood
it is then re secreted
in newly-formed bile.
04:19
So in our bodies about
95% of our bile salts
that are secreted
are then recycled.
04:26
So that we're only
making about 5% of nubile
each time it circulates.
04:34
The next major organ
that is important for the
functioning of the small intestine
is the gallbladder.
04:42
The gallbladder is a
thin-walled muscular sac
found on the ventral
surface of the liver.
04:49
It functions to store
and concentrate bile
by absorbing water
and ions in the bile.
04:57
It contains many honeycomb folds
that allow for it to
expand as it fills.
05:04
And then when stimulated
muscular contractions
are going to release that bile
into a duct known
as the cystic duct.
05:14
This is going to then
flow into the bile duct.