git + liver, pancreas & spleen
TRANSCRIPT
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Git + liver,
pancreas and
spleen
Special thanks to:
Nur Afiqah
Ainaa Nadia
Najwa Aiman
Nur Atiqah
Noise noise noise.
However I forgot to tell you that we have a general organization of the
muscular layer in the GI tract. We have two layers, one circular and one
longitudinal. But we have sections, and in the stomach we have third layer
which is oblique layer.
So in esophagus we have two layers, in stomach we have three layers, insmall intestine we have two layers, the same as the esophagus.
In the large intestine now we have another exception where instead ofhaving extra layer, no, the longitudinal layer is actually abbreviated with
three bands. We call them teniae coli. This band, on either side we have
another two. So the longitudinal layer, muscular layer in the large
intestine is not complete. It is limited to three bands, we call them teniae
coli.
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So lets start and to mention the part of the large intestine, which youmay know from your biology.
That ileocecal valve, which guide the passage of substances between the
ileum and the cecum. So the first part of the large intestine, we call it
the cecum. Its a blind-ended pouch, which lies below the ileocecal valve.It terminates in another point valve, we call it the appendix.
Well talk about appendix and the Mc Burneys point, which is a differentpoint to the location of the appendix. This teniae coli, Ive mentioned that
it has three bands. They all come together to make the muscular wall ofthe appendix. Alright?
The second part is the ascending colon. It ends at the right colic flexure.
This bend in the large intestine, we call it a flexure.
Noise noise noise.Things related to the large intestine, we call it colic. Its on the right
side, so its right colic flexure or we call it hepatic flexure, because it is
posterior to the liver. Then we have a transverse colon, it terminates at
the left colic flexure or we call it splenic flexure.
We start with the descending colon and the small ending with the rectum,
which is actually in the pelvic cavity.
We have differences between the large intestine and the small intestine.
As Ive mentioned, instead of having a complete longitudinal mu scularlayer, it is only limited into three bands, we call them teniae coli. You
notice that we have fatty deposits, or fatty tags, on the large intestine,
we call them appendices epiploicae (they are not found in small intestine ).
In the small intestine, we have a smoot h surface. Here the surface is
sacculated. This sacculation or each segment here, we call it haustra. And
the movement of things in the large intestine, we call it haustration. Ok?
Larger caliber, if we compare a film small intestine and a film large
intestine, of course you can see the large intestine will h ave largerdiameter or larger caliber. Also we have except for the duodenum,which
is relatively fixed,the rest of the small intestine is mobile, unlike thelarge intestine which is fixed. Especially the ascending and the descending
colons are fixed, so limited mobility.
These are the main characteristics that differentiate the two types of
intestines, the large and small intestine.
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Now we will shift and talk about the accessory organ of the GI tract.They are not part of the tract, they are accessory to it, namely liver,
pancreas and spleen.
Lets start with the liver.
It is the largest INTERNAL organ, and I said internal because if youconsider the skin to be an organ, then skin is the largest organ in the
body. So to avoid any controversy, we say it int ernal organ. It is thelargest, located on the right side. It has metabolic function, regarding
the metabolism of carbohydrates and protein. It has access ory digestivefunction, by producing the bile salts, which got secreted and emptied into
the duodenum plus blood filtration. When the body absorbs nutrientsfrom the small intestine, the blood now is loaded with the nutrients plus
whatever else that enter the GI tract. Bacteria, or maybe foreign
objects.
Were talking about molecular (). So these go to the liver for
detoxification and filtration. We have two surfaces for the liver. Onesmooth, the other is flat, and irregular. The convex, superior anterior
surface, or the diaphragmatic surface, it is shaped this way because itwill fit under the dome of the diaphragm. The inferior aspect of the
dome, is concave. So we need a convex surface to fit under the structure.
The visceral surface, which lies in contact with other viscera, like the
stomach, esophagus for example, is flat and irregular. I think irregular isthe right term for that.
So as Ive mentioned, superior anteriorly, the liver is bounded bydiaphragm. Its not in an int imate contact with the diaphragm. There is
space, we call it the subphrenic space. And the liver is suspended to thediaphragm by a ligament we call it falciform ligament. So if youre
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dissecting the abdominal organs out, you need to cut certain ligament t obe able to take the liver out. One of them is the falciform ligament.
Superiorly, we have an area of the liver that is not covered with
peritoneum, we call it the bare area. Bare means naked.The bare area of
the liver. Why? Because you notice the falcifo rm ligament does notcontinue all the way. It splits to form the left triangular ligament, leaving
a bare area of the liver. And this is one of the areas in the liver that is
not covered with the peritoneum. We have another two areas, we will
learn about in a moment.
This is just a sagittal view, to show you the location of the liver under the
dome of the diaphragm. You notice that , there is a space here, subphrenic
space, and Ive mentioned in the two lectures ago, the liver is also
connected through the lesser omentum or the hepatic duodenum ligamentto the duodenum. It is also connected, as Ive just said to the
anterior abdominal wall and the diaphragm by the falciform ligament.
One thing maybe I forget to tell you about. In the introduction weintroduce the idea of bursa right?
Bursa is a sac, a serous sac that is made to reduce friction. You remember
that when we talk about bursa in the knee joint? The lesser sac of the
peritoneum sometimes we call it the omental bursa, because it reduces
friction due to the mobility of the stomach. So if you hear the omentalbursa in the exam, I mean the lesser sac. Dont tell me you ve never heardabout it.
This is a superior view of the liver, it explains what I meant by the splits
of the falciform ligament. This is the falciform ligament, you notice it
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splits leaving a bare area here. The same thing happen with the coronaryligament, it splits leaving a bare area, uncover ed with peritoneum.
So together the bare area of the liver, located on the superior surface, it
is one of the areas that is not covered by peritoneum, we still have
another two.This is the visceral surface of the liver, and this is not the anatomic
position. Because if the liver is in anatomic position I cant see all ofthese. This should be the infero-posterior surface. So part of the
surface, I should not be able to see in anatomic position. It is justpositioned this way, so that we can study different structures. You see
its flat, irregular due to having impressi on for organs. Whenever organslies in close proximity one to another, it leaves an impression.
You remember the impression in the lung? For the inferior vena cava for
example, and the aortic arch. Here we have impressions. Gastricimpressions is not clear here, and usually we can see an impression for the
esophagus. In the right side we have impression for the kidn ey and the
right colic flexure. These are the targets for the practical exam 2. And
the fossa, it is covered with peritoneum, except in two places, the porta
hepatis (hilum of the liver), which is where the portal triad enters or
leaves the liver. Remember that when we say portal triad, were talking
about hepatic vein, hepatic artery and the hepatic duct.(in the slides,it iswritten hepatic artery,portal vein,and bile duct.Anyway i think its the
same.)
Remember, portal triad talk about hepatic vein, hepatic artery and
hepatic duct. These are portal triad. So, at the portal hepatis the v isceral
surface is not covered with peritoneum also if we removed the gall
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bladder, this is the gall bladder, if we removed it, the surface of the liver
underneath, it is not covered with peritoneum. So, these are three places
in the liver where diaphragm is covered with peritoneum, two in the
visceral surface and one area in the diaphragmatic surface. I just told you
about portal hepatis which is the hilum of the liver and its components.
Let's talk about lobes of the liver. What do I mean by lobes? It's part of
the border near the liver that separated by fissures or by ligaments. So,
I have an anatomical boundary that subdivide the liver into lobes. So, we
have four. Right and left lobe, plus the caudate and quadrate lobes. Now
this is anatomical subdivisions. What about the physiological? Only have
two, right and left. Quadrate and caudate, even though they are closer to
the right, actually they belong to the left lobe. So, the arterial supply and
the ducts that collect the bile actually is the same, for the left lobe,
quadrate and caudate. Did you get the idea how physiology is different
from anatomy sometimes? We have a main division or main line heart
dividing the liver into right and left which is the falciform ligament. Ok?
So, even if I don't know the anatomy and I have the liver, I will see they
have two parts, right and left. If we look at the visceral surface, we will
see another landmarks and boundaries that define extra lobe. You see
here we have an extension of falciform ligament, and here the gall
bladder, isolating parts of the right lobe and it has quadrangular in shape
we call it quadrate lobe of the liver. The same thing on th e top, the
ligamentum venosum that I will define it to you in the moment, the hilum
of the liver and the inferior vena cava they also isolate part of the rightlobe which we call it caudate lobe. So, this is anatomy. We look at the
shape, we saw that we can actually subdivides the liver into different
areas depending on having landmarks t hat we find in those subdivisions.
Now, physiology they stated what the liver do.
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For example, the duct that collects bile, we don't have separate duct for
the quadrate, caudate and the left. They all drain into the same duct.
Same with the arterial supply. This is why we say by physiologically we
have left and right. What about the caudate and quadrate? They belong
to the left by physiology. I just told you about the quadrate lobe, the
caudate lobe and their boundaries, one thing to tell you is about
ligamentum venosum. I told you that the ligamentum of teres is actually
the reminants of the umbilical vein that carries the blood from the
placenta to the foetus and where it gonna pours? in the hepatic vein. Does
the liver in the foetus matured enough to accommodate all the blood that
comes? No.
So, the body of the foetus will develop a mechanism, so that the blood will
bypass the liver and go to the inferior vena cava. So, not all the blood
that comes from the placenta will go through the liver. Some of it will
bypass the liver and this is done by the ligamentum venosum of course
the blood vessels, now the reminants, we call as ligamentum venosum.
(A student asking a question to the doctor)
Doctor : Yup, does the liver able to take all these nutrients and do the
metabolic functions it is supposed to do ? No.
Same idea in the lungs for example, for the foetus. The blood is pumped.
The oxygenated blood is pumped to the lungs for oxygenation, right? Not
all the blood of the foetus will go to the lungs. We have a bypassmechanism because the lung is not matured enough to do oxygenation for
all the blood, we call it ductus arteriosus. It is a blood vessel that ..in
the foetus, connects the pulmonary trunk to the ascending aorta or arch
of aorta, I can't remember exactly. It is another bypass mechanism. So,
the whole point I told u about lungs is about bypass mechanism, it is
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something you have seen before. Anyway, these boundaries are the reason
why we said we have quadrate, caudate lobe, right and left.
Let's talk about the ligaments of the liver and I'm g onna repeat thisagain, I told you, were not talking about fibrous dense as the rest of the
ligaments in the body. Were talking about duplication of peritoneal layers.
We have the falciform ligament which attaches the liver to the anterior
abdominal wall and the diaphragm inferiorly. This falciform ligament
encloses or houses the ligamentum teres, superiorly this falciform
ligament will split to coronary and left triangular ligament. And this spli t
is the reason why we have a bare area of the liver.
This falciform ligament is split and goes superiorly to left triangular
ligament and coronary ligament. This is a superior view. If you notice in
the right side we have the coronary ligament. The coronary ligament meet
together to form the right triangular ligament. And this right triangular
ligament will connect the liver to what structure? The diaphragm, again.
And in the left side we have left triangular ligament which also connect
the liver to the diaphragm. So, we have several connections of the liver
and this is what suspend the liver in its place in the right hypochondriac
region.
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Inferior ligament, we talk about t he ligamentum teres or we call it the
round ligament of the liver, reminant of the umbilical vein, ligamentum
venosum which I already defined it to you. And this picture here actually
explains the location of these vessels.
This is the vein from umbilicus that empties the blood in the left side of
hepatic portal vein. The blood should go to the liver for filtration. But, we
have a bypass mechanism that takes most of the blood and preventing it
from entering into the liver and empty it immediately into the inferior
vena cava. The reminants of this structure becomes ligament s of the
liver, ligamentum venosum and ligament of teres.
(A student asking a question to the doctor)
Doctor : What vein are you talking about? Umbilical vein?
(The student said something)
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Doctor : Now, forget the left lung. This is the venous system that we
discuss. ok? We will talk about it later. We see how the blood is collected
from the GI tract and it will go to hepatic portal vein. Hepatic portal vein
will have right and left side, going to the liver. After filtration, the blood
will be collected and go to the inferior vena cava to be returned to the
heart. In the foetus, one tributary of the left hepatic portal vein is called
the umbilical vein. It takes blood from the placenta to the liver of the
foetus. Are you clear so far? Now, because the liver is not mature enough
in the foetus, not all the blood will go to the liver. We need to take some
blood directly without filtration to the inferior vena cava. How do we do
that? We have a vein connecting the left side of the hepatic portal vein
before it enters the liver to the inferior vena cava immediately. And this
will disappear when the foetus is delivered and they become ligaments in
our body. They are not needed anymore and were not surrounded by
placenta anymore and we have mature enough .
This is just a review for you, now lets talk about blood supply to the
liver. Blood comes to the liver for two reasons. first li ke all other organs
in the body it needs to be oxygenated. so this is done through the hepatic
artery, which is a branch of the celiac trunk of abdominal aorta. so it
brings oxygenated blood and this marks 30% of the blood that enters theliver. 70% of the blood that enter the liver is actually for filtration. it
comes through hepatic portal vein. The blood comes through the hepatic
portal vein which collect the blood from the GI tract and this blood is
loaded with nutrients and sometimes maybe toxins or bacteria or
pathogens that needs to be filtrated. Hepatic veins are now veins that will
collect the blood again from the liver and empty it into the inferior vena
cava. They open immediately into the inferior vena cava.
Another major vessel in the liver is the bile duct. It carries bile salts
from the liver to the GI tract and we have a duct system for that. The
product is produced in the liver and it is stored and concentrated in the
gall bladder, which is a pear shape structure that lies underneath the
liver.
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So,
on c c nd
ogetherto
orm commonhepatic duct.
he
ile
illgotothegall
ladder
to e
toredthereanduntilthemomentisright, ill eexcretedto
cystic duct, thatmerge ithin cystic ductand commonhepatic duct e
callitthe ileduct.
hestory doesnotstophere, the ileductsometimes ill
ointhe
pancreatic ductattheampullaof ater. s esaid, the common ileduct
illmergeinpancreatic ducttoempty intheduodenum, hichisthe
secondpart.theampullathatisformedy thetwoducts, the
ileduct
andthepancreatic duct we callittheampullaof ater. nditsgoingto
empty throughduodenalpapilla, themajorduodenum.
heleftandrighthepatic ducts, commonhepatic ducttogetherwiththe
cystic ductwillform common ileductwhichpasses ehindthefirstpart
oftheduodenum.ndthen, the
ileductwillmergewiththepancreatic
ductatthe mpullaof Vater. hisswellingherewe calltheampulla.
Nowwewillshifttothepancreas. Pancreasisanotheraccessory organof
the! "
tract."tselongatedinshape, triangularin crosssection.
"thas
othendocrineandexocrinefunction. # ndocrinemeansithassecretions
thatareemptiedimmediately inthe loodwhichwe callthemthe " sletof
$angerhansandithasanexocrinefunctionswhicharesecretionandare
Ampulla of Vater
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emptied in another system which is here, the GI tract or the duodenum.
Mainly, the secretion for the exocrine parts are hydrolytic enzymes which
aids the digestion in the GI tract.
The endocrine mainly were talking about insulin and the glucagon which
are responsible for carbohydrate metabolism. The pancreas is a
retroperitoneal organ except in the tail area. The tail area will be house
where the mesentry of the spleen. (Im gonna sho w you a picture in a
montme). So we have four parts of the pancreas, the head, neck, body and
the tail. The head actually is housed within the duodenum. The duodenum
is c-shape, it looks like letter C. so if we have stru cture fitting there it
will be disc-shape .so that is the head of pancreas. The neck, always in
anatomy the neck is a constriction in the organ we talk about. So its a
constriction between the head and the body.
The duodenum is c-shaped. So the structure which is the head of
pancreas will be disc-shape. Then we have a constriction which is the
neck, the body and ending with the tail. One special thing about the tail,
its intraperitoneal. Unlike the rest of the pancreas, where it is covered
by the peritoneum because it lies in intimate contact with the splenichilum.
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How is the pancreas supply the blood ? Its through splenic artery plus
the superior and inferior pancreaticoduodenal arteries . we will describe
the blood vessels for the abdomen in detail and the venous sy stem in the
next two lectures. And we will see the splenic artery is a branch of the
celiac trunk, the superior pancreaticoduodenal artery is the branch of
the superior mesenteric artery , the inferior pancreaticoduodenal artery
is a branch of the inferior mesenteric artery (a nd the venous region
drainage drain expile the corresponding vein). % eins that have the same
name, which will empty in the portal system, not the systemic circulation.
Now we will finish the lecture by talking about the spleen which is
intraperitoneal structure, it is the largest single mass of lymphoid tissue
in our body. Lymphoid tissues are everywhere in our body in manylocations but this is the largest mass of lymphoid tissue located in the
left hypochondriac region. Its attached to the stomach by th e
gastrosplenic ligament. gastro means stomach. splenic, and attached to
the left kidney by the lenorenal ligament sometimes we will call it
splenorenal the name used in the text book is lenorenal ligament.
And these ligaments, if you notice that lenorenal ligament is an extension
of the peritoneal covering of the spleen. it covers the blood vessel that
are reverting or going inside the spleen plus the tail of the pancreas. So
the lenorenal ligament has structure within it, a splenic artery, splenic
vein and the tail of the pancreas.
What about the gastrosplenic ligament? The superior view we can see
that the blood vessel which is the short gastric artery and left gastric
gastro-epiploic artery. They are housed within the gastrosplenic ligament.
As we said in the first lecture, peritoneal structure, whether they are
ligament, mesentry etc, they are important for carrying the blood vessel
to different abdominal organs. Blood supply to the spleen by the splenic
artery which is the largest branch of the celia c trunk. It has tortius(?)
back way until it reaches the spleen. It splits into six branches.
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Thispictureisinaccurate(?)ithas(inthree)(?)itshould & esix & ranches.
'ndthe
&looddrainageisthroughthesplenic
(eintotheinferior
mesenteric ( ein.
*No comment will be entertained*
SEKALUNG PENGHARGAAN BUAT SEMUA YG TERLIBAT DLM
PEMBUATAN LECTURE NOTE NI. MOGA ALLAH MEMBALAS JASA
KALIAN DENGAN GANJARAN YG LEBIH BESAR DI AKHIRAT
KELAK
INSYAALLAH, ALLAH YUSAHHIL UMURUNA. ' ) 0 N..
1 Y JJ