the

Gallbladder and biliary tree (anatomy, gallstones)

hello you guys probably seen the title

of the videos you know what I'm gonna

talk about but I'm gonna talk about for

the sake of structure the biliary tree

the biliary apparatus the bile ducts the

gall bladder

you know bile stuff right I guess the

aim is so in recent weeks I've been

talking about three amigos right I've

been talking about structures within the

abdomen so we'd be looking at the liver

which makes the bile we'd be looking at

the duodenum which receives the bile

we've talked about functions of the

small intestine we've talked about bits

and bobs so we've kind of you know

circled our way around the biliary tree

so now I should lay down the structures

of the biliary tree and we'll follow

them from the liver to the duodenum

we'll name it all stuff like that

all right bile is made by the

hepatocytes in the liver and bile hat I

mean it's got those two main functions

or two main functional ideas here one

bile is waste that's going to be

excreted and that's the pigment part of

it

so bile within the gall bladder we've

got a gall bladder on here

booze and noise take the gall bladder oh

yeah look say the gall bladder is

typically green and won't meet the sect

we see the gall bladders green in fact

we see the region of the abdomen around

it is also stained green so bile within

the gall bladder has this green pigment

so that's the waste part and we talked

about it off probably in the liver or

maybe in the large intestine one we

talked about how that green pigment that

so we're talking about bilirubin and

stuff like that right in there and

stucco billon how that's the waste

product part of the bile that's going to

be put into the small intestine and then

is eventually you know get excreted from

us that's what makes feces brown that's

what gives you the brown color and the

other part the other functional

of pile is that it emulsifies facts

within the duodenum and in fact while

the liver is constantly producing bile

the gallbladder as we'll see it has a

muscular layer within it and when a

fatty meal enters the duodenum that's

what causes the gallbladder to contract

and squeeze by either gallbladder and it

causes the sphincters that would

normally stop file from getting to the

duodenum to relax and open and and bile

is then secreted into the duodenum as a

result of that fat within within the

duodenum which is kind of cool and most

phase the fasting helps in indigestion

of fast we don't have a look at the

liver video the small intestine video

the large intestine videos don't have a

look at all those videos to talk about

that to look at what we say about that

now repetition right in anatomy so I'm

repeating stuff I've done before but

there is a lot of repetition in anatomy

because however we chop up the human

body we tend to approach bits of it from

different angles at different times and

repetition is good because it cements

learning the reason I can remember stuff

is because I teach it over and over and

over again so it sticks in my head

eventually right I know that the way you

study for exams and you learn is you

keep looking the same thing over and

over again you use repetition to cement

things in your mind as well so while you

might be watching this video thinking oh

I know this I've heard this before

oh he's repeating himself that's good

hold on to that feeling that's it there

should be a nice warm fuzzy feeling you

should be feeling I know this I've

learned this I understand this this is

good right so try not to get annoyed by

the repetition try and you know embrace

the repetition and embrace your own

knowledge and understanding and what

we're going to do is we're going to

layer on top of it although some of this

stuff you may well have seen before them

could be cementing your understanding

and knowledge right all right we do

repetition on purpose so right if we

stay in the liver then we've seen how

the livers go right lobe left load

called a load quadrate lobe but and

we've seen how there are lots of

live a lot sinusoids that was a thing

wasn't those hexagonal sinusoids chests

shapes right within the liver there are

lots of lots of segments kind of

functional segments of the liver and

each one of those segments is draining

violence the biliary tree so imagine the

biliary tree inside the liver is like

the respiratory tree inside the lung you

know it there's loads of loads of

branches and it's really really

complicated so if we were to look at the

intra hepatic biliary tree it would be

really really complicated but we look

here so this is what we would call the

porta hepatis

well the hilum of the liver maybe this

is where and we've got a number of

things entering and leaving the liver

and here and it depends again how deeply

you cut what you can see you can see

some you can see yeah there's a lot of

green tubes there we can see the portal

vein we can see the hepatic artery

proper the supply or native blood to the

liver we can see the inferior vena cava

here which the liver is wrapped around

and we can see there's the gallbladder

there and we'll get to that in a moment

what we can see is we can see some of

these green tubes that seem to be coming

out of the liver now we would call these

hepatic ducts you might be able to

determine left and right hepatic duct so

you might see a whole tree of hepatic

ducts and these are then draining the

bile from the liver itself and they come

together and form a single hepatic duct

and that single hepatic duct gets called

the common hepatic duct and you can see

on this one oh this one's a bit better

there's a gallbladder see I got I got

this sticky I've got this pointy thing

that's bolted in that's kind of getting

in the way but um we can see here we can

see two hepatic ducts coming together

and forming a very very short common

hepatic duct right common matic ducts

will leave there now here's the

gallbladder so look if that's if that's

anterior and is the gallbladder there so

as we as we lift up the

the liver that's where we see the gall

bladders the gallbladder is held to the

liver it's stuck on to the liver it's

covered in peritoneum just like the

liver is covered in peritoneum it's you

know you might think that the

gallbladder is kind of upside down and

if you see what I mean like the it has a

body a fundus and a neck so the body's

here the fundus is the is the is the

large open space but at the end T and

here's the neck so it's kind of you know

what I mean if I turn this around so the

neck is up here in the I think it's

upside down but does that make it worse

fuse that makes sense you always seems

bit upside that way if you have it if

you've got a container right and you

want to empty it you kind of have the

bottom of the container down there we've

kind of got the container open you know

the containers like the neck of the

containers up there you kind of need to

do that to Paul right see so the

gallbladder feels like it's upside down

to me anyway that's just me now from the

gallbladder we have the cystic duct the

cystic duct goes and joins the common

hepatic duct and when the common hepatic

duct and the Cystic go to join then we

call it the bile duct it often gets

called the common bile duct

but that's new that's kind of needless

it doesn't need to be called a common

bile duct do you see how the common

hepatic duct gets called the common

hepatic duct because of all those other

lots of little hepatic ducts come

together and form a single herb I think

that that's what gets called the common

hepatic duct but the bile duct is where

the cystic duct and the common hepatic

duct come together so it's just piled

just from that point then when the

cystic duct meets the common hepatic

duct that's when they call it the bile

duct and then that goes all the way

around to the duodenum you can call it

the common bile duct if you like that's

fine I think is the contemporary term is

bile duct you'll find lawsuit it's

called the common bile duct so then if

we take the liver right and there's the

star of the bile duct

there's the bile duct to there now if we

take the stomach out you can just about

see the bile duct here whereas the

cystic duct was maybe three centimeters

long the common bile duct is going to

it's gonna pass posterior to the

duodenum and posterior to the pancreas

and then it's going to come and meet the

main pancreatic duct and duct into the

duodenum at the same site there's the

common pancreatic duct and that's

because of how it's developed that's

because of the embryology but this means

that the bile duct is maybe 5 10 15

centimeters long and do you remember

that between the liver and the stomach

we have the lesser omentum that's the

counter tissue she connecting the two of

them and in the free edge of the lesser

omentum here that's where we find the

bile duct running with the portal vein

and with the hepatic artery problem all

right so it's the reason that the bile

duct passes posterior to the duodenum

and posteriors the pancreas is because

embryologically

when we were an embryo we were nice and

simple I was my simple space with

innocent at a simple gut tube running

the length of the the main cavity inside

the embryo and I was held onto the

posterior abdominal wall by a dorsal

mesentery this being the stomach at the

level of the stomach we had the dorsal

medial gas trium gas the stomach and a

ventral music Astrium and in the ventral

music a stream we see or we saw a bud

coming off now forming the liver and

from there bud also forming the gall

bladder and forming a bit of the

pancreas and in the dorsal music gas

room we saw another bit of pancreas

forming and then the stomach not really

good this the stomach as it develops it

rotates right which pushes the duodenum

into a c-shape so so as it rotates and

forms the C shape it it pulls so if that

tube was sticking out anteriorly to the

gallbladder in the liver it pushes the

the live around to the right side so it

pushes that that bile duct around so

it's going to run posterior to the

duodenum then if that makes sense but it

does so bile duct runs posterior through

Judean and posterior to the pancreas

and then it joins with the main

pancreatic duct so that's that a

herringbone shape you can see here's the

pancreas there's the this the curve C

shape of the deity duodenal is the first

part second part third part fourth part

and you can see there's the the bile

duct there next to the portal vein those

have both come out of the lesser omentum

together and the bile duct look how it's

running posteriorly to get into the

duodenum and then within the Judean and

we see this ampulla don't we this little

lamb a little volcano all right a little

volcano in the in the descending part of

the second part of the duodenum and at

that point that's where the exocrine

secretions of the pancreas get passed

into the duodenum and that's where the

bile from the bile duct gets passed into

the duodenum so at that papilla where

all that stuff gets secreted into the

duodenum just before then that that tube

dilates a little bit right so we have

what we call an and pull er because

latin you have like Latin pots which

contained wine and stuff that's how they

were shaped they were called em pullers

and that's how they were shaped and

that's what we see just before the those

ducts enter the duodenum we see this

ampulla which the old term for it is the

ampulla of Vater the contemporary name

is the hepato pancreatic and puller

which makes complete sense because we

have stuff from the hepato the liver and

stuff from the pancreas going in there

and between the ampulla of Vater and the

duodenum we have a sphincter of smooth

muscle that's the sphincter of Oddi and

his new name is the hepato pancreatic

sphincter so if that's thing that is

closed then bile cannot enter the judean

of an either connects with coin

secretions from the pancreas now just

before the main pancreatic duct is

joined by the bile duct there's another

sphincter so there's a sphincter of the

bile duct which can separately close off

the bile duct

before the ampulla of Vater about a

pancreatic ampulla however the old names

are saying it and this is important

because this explains how the gall

bladder works probably more importantly

this explains how stuff goes wrong with

a gall bladder right you'll see what I'm

talking about in a minute we'll get

there right okay so the liver it's

constantly making bile it's constantly

making bile because it's constantly

doing its 501 special functions that the

liver has its costly making file and

that bile is going in through the

hepatic ducts and the common hepatic

duct and then it's going into the bile

duct and it's draining through the bile

duct and it gets all the way down here

but you haven't just had a fatty meal

you don't need bile in your duodenum

right now we need to save this for later

so those sphincters the the sphincter of

the bile duct and the sphincter of Oddi

hepatic pancreatic thing too are closed

which means that that bile has been made

by the liver then backs up the bile duct

and when it backs up as far as the the

join between the cystic duct and the

common hepatic duct it starts backing up

into the gold bladder so that's what the

gall bladder is for it stores bile I'm

sure you knew that but it's not like the

bile goes from the liver to the gall

bladder then to the duodenum no the bile

goes from the liver down to the duodenum

but the sphincter is closed so then it

backs up into the gallbladder and the

gallbladder it's actually structured

very similarly to other strategies of

the GI tract there's an epic I'm not

gonna show you the histology there's an

epithelial mucosa and then there's a

lamina propria just the connective

tissue holding that together but then

there's a muscularis externa so there is

a muscular layer a layer of smooth

muscle of the gallbladder that's under

autonomic control and those fibers those

cells are all running in lots of

different directions then there's a

serosa over the top of that so

the gallbladder can hold about 30 35 mil

maybe a bit more bile normally in most

people but it can't expand it can

stretch to hold ten times that much if I

say if needs to be if things go wrong if

there's a blockage

now what happens normally is that you

have your nice meal you have you or your

fatty stuff in there and the gallbladder

is innervated by the sympathetic and the

parasympathetic divisions of the

autonomic nervous system the sympathetic

nerves get there around the celiac you

know through the celiac ganglion around

the sealy out places and following the

arteries up here the parasympathetic

aware do the waiver the parasympathetic

nerves that supply the gallbladder come

from the vagus nerve absolutely cranial

nerve 10 everything it's all the vagus

in the denne

so the parasympathetic innervation from

the vagus nerve can cause last move

muscle to contract it can cause the

gallbladder to squeeze by oh eight of it

and the bile to pass then down the

cystic duct and down the bile duct and

into the duodenum because it also the

parasympathetic nervous system will also

cause those sphincters there have passed

a pancreatic sphincter and the sphincter

of the bile duct to relax so the bar can

go into judean but to be honest that's

not typically how it works when we eat

fatty foods when the fatty food gets

into the duodenum the magic of CCK

happens cholecystokinin cola coat at CH

o le Cola Cola I know it sounds like a

drink I never thought of that bad before

but that comes from the Greek word for

bile so the Greeks in the Roma's they

rinse their four humors you had about

the four humors either green balls black

bar and the bloody a they really weren't

on to something with that anyway Colin's

bile so CCK cholecystokinin

is a hormone made by the enter o

endocrine cells within the small

intestine in the duodenum so when the

duodenum receives fatty foods the CCK

is released by those cells into the

blood cause hormone then kicks off

everything like because it goes into the

bloodstream goes around the body and

it's the CCK that causes the the

gallbladder to contract and the

sphincters to relax that allows bile to

go into the duodenum so it's not

triggered by nervous innovation is

triggered by cholecystokinin while we're

talking about it the gall bladder is

supplied with blood by the Cystic tart

Cystic artery which is also supplying

blood to the ducts and stuff that comes

from the right hepatic artery but the

venous drainage of blood from the gall

bladder actually goes back into the

liver it doesn't doesn't go yeah so you

might think your Cystic artery cystic

vein no so the the Cystic artery

supplies blood to the gall bladder over

there blood drains from the gall bladder

back towards the liver maybe right at

the right part of the poor vein may be

delivered directly that sort of thing so

that means that the lymphatic drainage

of the gall bladder is similar right so

the lymphatic drainage is going to

follow the venous drainage so the

lymphatic drainage is back towards the

porta hepatis so nodes of the porta

hepatis and that sort of thing so you

know if you're worried about where tumor

cells are going they're going to go

towards the liver so another thing to

note is that the gall bladder does

actually have an action upon the bile he

actively transports sodium ions out of

the bile which of course through osmosis

will take water and other ions with it

so the bile that goes from the liver if

it was to go from the liver strains the

judean and that would be different to

the bile the stores in the gallbladder

like the garlic or guys a little bit

more concentrated and by doing that it

raises a risk of stones do bladder

stones which you've probably also

considered as well before we get the

stones I'd like to point something else

out which is that while the gall bladder

is within the median tree the peritoneum

covering the the liver

when we when we lift up one to look at

the gallbladder we always lift up the

liver I want the little bladder sits

anterior to the superior part of the

duodenum and whenever we do this in the

cadaver as I mentioned earlier we see

this green stain in this area of bile

that's kind of leaked into this region

so just as an anatomical note for you

guys you know if you if you're looking

at across sections through the abdomen

the dual bladder is between the liver

and the superior part of the duodenum

that's where it lies okay but because

it's surrounded by the peritoneum

surrounding the liver you can pull the

liver away from the stomach and the

duodenum and then you have the lesser

omentum between the two so we talked

about the bile having two separate

functions some of it being just excreted

excreted and there apart being beautiful

emulsify fats the bile salts the

functional part the the part that

actually emulsify fats that gets

recycled so the terminal ileum reabsorbs

much of the bile salts and reuses them

you mentioned that in small intestine

video I've got to mention that here okay

so now we've got the structure of the

biliary tree the reason that's important

is that we can work out what happens

when bits of it get blocked so gall

stones can form if you know it's kind of

like an the bile gets too concentrated

you get too much cholesterol or too much

of another thing I common bodies and

anyway Paul stone so gall stones are

interesting we can look we can apply our

Anatomy to these so if in many cases

gall stones are quite small and they'll

pass along the biliary tree and get

passed into the duodenum and flushed

away and it's not a problem

most gall stones that do occur occur

without any signs or symptoms at all

but sometimes gall stones are large

enough as they get lodged even if they

get lodged often it's a waiting game

wait for the patient to pass the

gallstone along to the duodenum but they

call symptoms and sighs one of those

signs be in pain so if we're accusing

the gallbladder as being the main site

in which gall stones

up here what would happen what would be

the signs and the symptoms that you

would see in a patient if the gallstone

occluded the the cystic duct now the

neck of the gallbladder has a spiral

gets called a spiral valve but a better

description is a spiral fold so there's

a spiral fold in the neck of the

gallbladder which holds the neck open

there's no sting to there just it holds

it open so the gallstone can pass into

the neck of the gallbladder maybe maybe

they'll get stuck there maybe they'll

get stuck in the cystic duct what's

gonna what are you going to see if the

gallbladder get if the if the if the

school stone gets stuck there we might

see pain in the upper right quadrant or

towards the center of the abdomen it

might lead to pain in the upper right

shoulder to the back it might lead to

nausea and vomiting so we might have

inflammation of the gallbladder which is

cholecystitis the information might not

be caused by a blockage here might be

caused by you know infection or an

autoimmune disorder or something else

but you might see inflammation of the

gallbladder in those signs okay but you

probably wouldn't see much else now

let's assume that the gallstone has

passed into the into the bile duct and

it moves along the bile duct and it

doesn't get stuck until so it goes all

the way down here and doesn't get stuck

until it almost gets into the duodenum

what signs and symptoms are you likely

to see now well bile will not be able to

get into the duodenum

if the cystic duct is blocked to the

gallbladder bile will still be able to

get from the liver through the common

hepatic duct through the bile duct means

the judean unless you still get the bile

out of the liver if the blockage is in

the cystic duct because the blockage is

down here

beyal cannot get out of the biliary tree

the duodenum so you can I have dialed

backing up into the gall bladder and

backing up into the liver what will you

see you'll probably see jaundice because

we won't be able to get rid of that

bilirubin so we'll have all those

physiological knock-on effects of of

collecting too much yellow pigment in

the skin so John this yellowing of the

skin yellowing of the sclera of the eyes

is a really good indicator of a problem

with lipid liver function isn't it but

we're also going to be blocking probably

the main pancreatic duct

so those exocrine secretions of the

pancreas also won't be able to get into

the duodenum so you're likely to get

acute pancreatitis and all the other

things associated with that here a lot

of pain and and the things we talked

about the pancreas video so what we're

talking about here is is is termed Co

cholelithiasis colon elias's yeah gall

blown a gallstone blocking the biliary

tree if it's possible for the patient to

pass that's though normally great my

surgeon buddies tell me they don't like

using surgery to fix this if they don't

have to they like to use lithotripsy

where they use ultrasound or they're

called extracorporeal shock waves sound

waves to try to break up the gallstone

into smaller pieces so the patient can

pass it normally so they don't have to

cut open the patient and if that doesn't

work and say the gallstone gets all the

way down here where it's almost in the

duodenum but it won't go into the

duodenum they like to use

ERCP endoscopic retrograde

cholangiopancreatography ER you see what

they like to use abbreviations how your

ERCP now what they do here is again they

don't have to open the abdominal wall or

even use any keyhole surgery they pass

an endoscope into the oral cavity down

the esophagus through the stomach into

the duodenum they get down here and the

endoscopes got camera and it's got maybe

a heated wire or a small blade on it

and they'll try and open the try and

make the the opening here the ampulla

a little bit larger so this the stone

can be passed into the into the Judean

and then passed away so the patient's

problems that way if that doesn't work

then yeah then for most people that use

laparoscopic surgery we just use keyhole

surgery make a couple of small holes and

what have you if if a patient repeat

gets repeated the gall stones then often

there's elective surgery to remove the

gallbladder to stop it happening again

and again they tend to using a keyhole

surgery to go in and remove the

gallbladder and take that away

gallbladder being the culprit of the

gall stones so that's the trick here is

remember your biliary tree so you've got

all those hip I think that's coming out

of the liver they come together to form

the common hepatic duct that meets with

the cystic duct which is coming from the

gallbladder and they join to become the

bile duct which runs posterior to the

Judean and posterior is the pancreas and

then ducts into the duodenum and we've

got those sphincters they're packet

hepato pancreatic sphincter and the bile

the sphincter of the bile duct before

the ampulla the hepato pancreatic

Gambler which regulate then bile

entering the duodenum and when those are

closed the bile constantly made by the

liver backs up and is stored in the

gallbladder remember that tree and then

you can work out where a gallstone might

have launched by the symptoms that you

see in your patient and the signs and in

most of these cases I think they use

ultrasound I think of course an MRI CT

images I use in exams but I think they

use alt you can use ultrasound to to

diagnose where the stone is but you have

to know what you're looking at all right

in terms of the biliary tree has to work

out where the stone is but but there you

get well done okay so that's it that's

the gallbladder and the biliary tree so

we we've joined the liver to the

duodenum so we've got that two-way flow

only all right good the reason I was

talking about the biliary tree this week

was because I've been teaching him

bloody and stuff this people didn't have

anything in my head I have to love a

look and see what we're teaching next

week and work out what I'm gonna do for

a video year to have got an exam the

week after next week and the lab is full

of students revising two weeks early

maybe they've gone away next week anyway

whatever it's good to see her there

hopefully their exam people's are we

good to see as well and they'll do well

my bra see you guys next week with

another fascinating anatomical topic I

mean how can you not be fascinating it's

us right it's us

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