We know where it goes in, we know where it comes out
and we know in between something useful happens.
Tonight, I will show you journey of a mouthful of food
along a seven metre of ingenious tubing.
I will actually unravel this woman's gut, literally.
And at the time I have finished,
her tongue will be here, her stomach here,
her liver, her pancreas, her small intestine, large intestine
and finally, over here, her anus.
It is sometimes said 'you are what you eat'.
But, in the case of the humble doughnut,
this is true in quite a surprising way,
because the doughnut is actually an elementary model of the way that we are made.
It has a mouth, an anus, some stuff around the outside
and a tube through the middle.
In her own case, the stuff around the outside has been elaborated into a head,
a body, arms and legs.
And the tube through the middle has got the lot longer
and a lot more convoluted.
But our central tube is vital because it is through this tube
that we take in food from the outside world and convert it into our bodies.
There is a lot of this tubing.
And it is quite amazing that it all fits into the abdomen in this way.
Our alimentary tract is stuffed in one of our body cavities.
To show you that, I have cut the whole body, frontally, in two parts.
And we look at the cut surfaces we see here the upper cavity for the brain
and the large body cavity here, the lung, in front, the heart.
But below the lung on this side, there the alimentary tract starts.
These the diaphragm is a liver, the stomach, the large and small intestine
There is absolutely no space wasted anywhere
and yet there is still room in here
for our intestines to writhe around as they propel our food along.
But this very economy of packaging means
that it is actually quite difficult to understand what connects to what.
So we are going to begin our journey at the very beginning, at the mouth.
And we show it at this body to be dissected.
The body is fixed.
This means we stop putrefaction by a chemical called formalin.
It also has the advantage that the organs become stiff,
they are not so flabby any more.
Of course, we had to suspend the body by those threads.
For anonymisation, we put this mask on
and we have the mouth open because we want to follow a piece of food along its journey.
The reason for having the body in the upright position
is because we wanted to show you the gastrointestinal tract
in the sort of position that you would normally see it when we eat a meal,
in other words in an upright position.
Digestion starts in the mouth by saliva
and this is produced by the salivary gland.
So what I do now, I open the flap of the skin to expose the salivary glands.
So in this demonstration we are going to use the analogy,
the perfectly reasonable analogy, of the gastrointestinal tract as a food processing plant.
And the processing starts with the mouth.
The mouth is our food hopper
this is the place where we take food in, where we crush it up
and break it into smaller pieces,
ready for transfer down to the business end of the gastrointestinal tract,
which is in the abdomen.
The mouth is actually a more sophisticated structure than it is often given credit for.
We have muscular lips, by which we can manipulate our food,
we have teeth of various different sizes and shapes to cut it up,
we have cutting incisors at the front, we have grinding molar teeth at the back,
we have salivary glands.
And I think this might be a good opportunity to use,
we have got a little mini camera here, to give you a closer-up view
of what is happening.
So you can get a slightly closer view of the salivary glands.
The saliva has two main functions.
Its main function is to lubricate the food,
ready for its journey down the oesophagus to the intestine.
But it also produces an enzyme - this is a special protein,
which digests, in the case of the saliva, starch.
So, if you like, this is nature's own toothpaste,
because once you have eaten a mouthful of food and swallowed it,
the saliva then starts to clean your teeth.
The other thing we have in the mouth is this strange prehensile organ, the tongue.
And the tongue is very sensitive and very well muscularly controlled.
It exists there to mix up the food and the saliva
and get a bolus of food ready to be transferred to the back of the mouth.
In the back of the mouth, there is a group of mussels called the pharynx,
which we use to swallow. And that's what we are going to see next.
To see the pharynx, we must open it from behind.
Therefore it is necessary that I take the back of the head
and also the neck itself off in one piece.
This takes a little bit of time.
We have pre-dissected the head a little bit, so we are a little bit faster.
So we see, aha, the brain actually is attached now to the back bone
and I have now to go here.. at the back end.. or to loosen the skin.
Marius, my assistant, thank you very much if you help me
So I have to go deep into here
The reason why we are approaching this dissection from behind
is because the oesophagus,
which is the next part of the gastrointestinal tract which takes the food down to the abdomen,
is actually located right at the back of the chest
and right at the back of the throat,
so the view that we will have in a moment when this block has been removed,
is actually a very difficult view to obtain.
This is a view that few anatomists actually attempt to do
and it is a view that few, even medically trained people, have ever seen,
because it is only rarely that this type of dissection is performed.
But it will give you the best view that is actually possible
of the location of the oesophagus in the body.
Just lifting that
And indeed, what I take off here, is the vertebral column,
here starting off the rib and here the brain with the skull,
the back of the skull.
So we don't need this because right now we want to look to the front,
we want to see the pharynx.
So I put this over here, gently
Well we now take the
skull aside, a little bit of hair to the side.
Then what you see here from the back is
the back of the mouth called the pharynx.
This is actually a muscle layer which I want to cut open.
And this goes down here,the connection down to the stomach,
running between the two lungs here.
The right lung and here, the left lung
And the pharynx is actually the last time when you swallow some food
that the food is under your conscious control,
because these muscles at the back of the throat are the muscles you use to swallow.
So when you decide to swallow something,
when you make the movement and push the food towards the back of your mouth and swallow,
these are the muscles that contract.
And you know when you swallow, your Adam's apple moves up and down?
That is because that is actually connected to these muscles.
So this is the last time your conscious brain is in control of food
and for the rest of its journey,
it is under the control of the intelligence of your intestines.
So what we see here, we see the back of the mouth,
with over here the uvula.
Here is actually the back of the tongue.
So I like now to remove more of this red material.
Actually that is mucus we injected, together with the formalin to prevent putrefaction
and make the specimen stiff.
We injected into the arteries red contrasting material.
It is also seeped through the tissue
and I have to remove it here, so we have a more clear view.
What I also like to do now is to take a needle
and actually when we open this door,
this muscle of the back of the mouth called pharynx,
when you open the pharynx to keep it open,
I take a dissection needle
and I put the dissection needle in here,so all the time it is kept open
and on the other side, I put in a dissection needle as well.
So now we have a full passage from the front to the back.
And I like to demonstrate this with a piece of food.
This piece of food is marked.
So this is a bit of plasticine that we are using to stand-in for a mouthful of food here.
It passes past the lips, past the incisor teeth
and then as we come round to the back
Actually in life, you would not go so far, you would swallow.
So I take it here and now what would happen?
This piece of food would
just travel along the
back of the tongue
and over this what I call the epiglottis.
The epiglottis which, actually, in this moment here, closes the windpipe.
And it goes around here, down here into the oesophagus.
I will open the oesophagus,the connection between the mouth and the stomach
and we just keep the food here.
This is actually quite a strange arrangement you see at the back of the throat here,
because the food has actually had to cross-over the air stream.
So when you swallow, the food has to pass by your windpipe
to get down to the oesophagus and this is really just an accident of history.
We evolved from a type of fish which had its swim-bladder or air-sack in front of its gut.
So when the fish then developed legs and stood up,
it turns out that our lungs are now in front of our oesophagus.
So in order to make sure that the food actually gets into the right tube,
we have this little trapdoor call the epiglottis.
And part of the machinery of the pharynx is that when you swallow,
the epiglottis automatically closes.
And, of course, sometimes it doesn't get it quite right
and a particle of food or some fluid actually gets into the top of the windpipe
and that is when we choke.
And we have a reflex there, then, to cough that out of the windpipe
and to make sure that the food hasn't gone down and blocked our lungs.
I demonstrate this here.
The piece of food comes out of the mouth to the back of the mouth
and now it approaches the epiglottis.
The windpipe closes, it goes here.
When a little bit might go in here, we have the coughing,
it would go back, but now this time it closes.
Wonderful, here it goes its way down to the oesophagus,
down here into the stomach.
Many of our organs are in very close proximity to each other,
so if something goes wrong with one organ, it can affect the functioning of another.
For example, if you develop a cancer in your oesophagus,
you can see that that cancer could make a hole between your oesophagus and your aorta
and that is a mode of death in people with oesophageal cancer
that the blood comes out of their oesophagus.
Conversely, you can see that if you have a cancer of the lung,
that can actually sometimes involve the oesophagus
and close-up the oesophagus and stop it working.
So these anatomical details, although they sometimes seem quite mysterious
and why would anybody want to learn about them in that detail,
actually are used by doctors everyday to understand the symptoms that they see in their patients.
Now I am about to take the tongue and the back of the mouth out
and, for that reason, I actually cut here along what is called the soft palette on both sides
and I loosen here, just right of the big arteries in the vein who up go to the head.
I loosen that and indeed, here, we have the tongue.
The oesophagus, although it seems to be just a conduit
running down from the back of the mouth to the stomach,
is actually also quite a sophisticated organ.
There is nothing in the body that is there not for a reason.
The oesophagus has mucus glands in its wall,
which also help to further lubricate the food on its journey down to the stomach.
And it also has to have a muscular wave,
which travels from the top of the oesophagus down to the bottom
to get the food down to the stomach.
So what I do now in front, here, is the windpipe,the trachea.
And I have to cut his windpipe through.
And what I see here is the opening of the trachea
and the opening of the trachea where I take this mucus out again.
And now, I take all the nerves away.
The oesophagus moves through the diaphragm into the stomach.
And the stomach, now, I have to approach from the front.
Therefore, I take the knife
and I will do a cut below the costal margin,just along the diaphragm.
So I am going now through all the muscles of the abdomen.
Tense abdominal muscles when you are not trying to,
is actually a medical warning sign.
There is a reflex that causes the abdominal muscles to tense
if there is infection or inflammation or sometimes other bad things happening inside the abdomen.
So a tense abdomen is referred to as guarding
and that is a medical warning sign
and is something that doctors look for if somebody is complaining of tummy pain, for example.
I actually cut here through three plates of muscle,
which protect the internal organs.
If you are able to admire your own abdominal muscles
when you get home if you can still see them anymore,
the front one is the one that runs up and down
that people like to show off in pictures, sometimes.
And that is called the rectus abdominus which is a straight up and down muscle.
But that behind that there are two oblique muscles
one making a fan in one direction,an external oblique
and one making a fan in another direction
and then behind that there is a transverse muscle.
So there is actually several muscle layers there that protect your abdominal contents.
And now, we are about to take all this abdominal flap down
and I like a little bit more to open the belly, take this flap down.
For any medical student, when you open the abdomen,
it is a little bit difficult to understand, so let me explain.
This is here, the liver.
To the right side, here, this is the stomach.
The stomach, actually, to the stomach is connected
a kind of connective tissue which looks like a kind of fur
this is called the greater omentum.
This has two functions,it is a flap of tissue that hangs down.
And one function is to store fat
it is a kind of internal winter blanket that we have at the front of our abdomen, here.
Now, men tend to store fat more in this greater omentum than women do,
which is why you tend to see more pot-bellied men than you do women.
And another feature of the greater omentum
is that if there is infection inside the greater abdomen,
this actually sticks to the area where the infection is
and so can help limit the spread of infection inside the abdomen
So, we don't need it now,
it obscures the view of the organs,
therefore I take this connective tissue away.
It is attached here, to the large intestines
and not to open the large intestine by accident,
I cut it, just from just below and just at the border.
So, John, that is your winter blanket okay.
And we take it over here.
And this is the large intestine.
And below here, is the small intestine.
So the viscera are actually arranged in the body cavities in a series of layers.
The gut is in front,
the liver is above,
the pancreas and kidneys are to the back of the abdominal cavity.
And the way it is all joined together is such that it is easiest to take out both the whole of the intestines
and its helper glands in one block, which is what we are going to be doing next
and then we will be able to demonstrate those various glands to you
when the block is on the table in due course.
Now I move with my hand between the peritoneum and the side of the muscles
and the back of the abdominal cavity to take all the organs out,
out just here, below the diaphragm.
So while it is possible to dissect the human body and take the organs apart,
we are not actually made in a way that is supposed to be taken apart,
so it can be quite tricky on occasions to achieve it.
Okay, so I take the liver down now, and here
I feel the oesophagus and there it is
and there is also the tongue from the front
and now it should be more easy to...
loosen the liver.
Marius, take your finger away, careful.
Large knife, large knife, yes.
And now I can take the whole abdominal specimen down.
We should be able to take out the last part of the
large intestines, the rectum with the anus that is here.
Knife.
So, absolutely gorgeous, now.
It is about 15 kg.
The last cut over here.
Yes, and I will place over here.
The liver,
the oesophagus,
the larynx,
the stomach,
small and large intestines.
So, to date, if we refer back to our mouthful of food,
it has travelled past the pharynx and the epiglottis,
down the oesophagus
and the next port of call is going to be the stomach.
So let's identify now, clearly the stomach.
And here, we see the oesophagus entering a large receptacle.
And this, actually, this here, is the stomach.
So let's have a look at where that is on a live person.
Over here we have Juliet, our resident anatomical artist and our fine specimen, Dennis.
Here is the oesophagus, running down behind his lungs
and here we have the stomach.
So the stomach is where the food lands about 4 or 5 seconds after you have swallowed it.
And the stomach has a variety of functions.
First of all, obviously, it acts as a storage receptacle for the food.
Secondly, it doesn't matter how much you wash or cook food
there are always germs, or bacteria and other things like fungi still on it
and we don't want these coming into us from the outside world.
Already, even though this is the first port of call in the intestine is deep within our bodies.
So one of the important functions of the stomach is as a steriliser.
The stomach actually secretes very concentrated hydrochloric acid.
This acts to sterilise the food, to help sterilise it.
The acid is sufficiently concentrated that if you got it on your skin, it would cause a burn.
But the stomach protects itself from this acid by secreting a specialised mucus,
which protects its lining from the hydrochloric acid
and stops that being a problem for the stomach.
Now as the food drops into this strong acid, it starts to fizz away.
And as we all know food, when you have eaten it, sometimes gives off gas.
It is an anatomical peculiarity that where the oesophagus comes into the stomach
is about a third of the way down this border of the stomach, here.
With a little dome of stomach above there called the fundus.
And the gas that is fizzing away inside of the stomach tends to build up in this fundus here
and make a little dome of gas
and then every so often you make a diaphragmatic movement,
push the gas down and it comes up the oesophagus as a burp.
So that is the anatomy, if you like, of a burp.
Another thing that the stomach does is that it secretes a special protein,
which begins the primary processing of the food in the stomach.
The protein is called pepsin and it begins to break up the food,
break up the protein of the food into smaller units.
There is, of course, a slight problem with this acid being present in the stomach
which is that the air in the fundus here
can actually pull apart the opening of the oesophagus into the stomach,
which is normally kept closed by a fairly lose sphincter.
And if that does get slightly pulled apart,
the acid from the stomach can get into the lower end of the oesophagus.
Now, the oesophagus is not protected in the same way as the stomach is from acid
and so that happens, it starts to inflame and irritate the bottom end of the oesophagus
and that is what we know as heartburn.
So, let's have a look at the stomach in the dissection specimen.
The stomach is a little bit crumpled here on the left side.
We have to clean it from the inside.
Therefore I just fill it up now with water.
And there, the stomach comes out in full.
Thank you.
Would you keep it here?
And now I will open it.
This filling of the stomach that we have just seen here
is what actually happens when you have a large meal
the stomach does dramatically change in size.
This is a little food, which, actually we placed here and the water pushed it down into the stomach.
We discovered our food.
The stomach actually has quite an impressive array of hormone secreting cells.
And these hormones circulate in the blood to the distal parts of the gut
and tee-it-up to receive the food when the stomach is ready to release it.
The stomach also has a complicated array of sensory receptors.
And these identify the state that the food is in within the stomach.
Sometimes if you take a bad mouth full of food,
say with toxins in it, or with something in it that isn't good for the body,
the stomach may decide that the food is not good to be passed on to the rest of the intestine.
And when that happens,
these senses are responsible for inducing a wave of contraction to go in the reverse direction
and push the food back out of the stomach up the oesophagus and out.
Which is obviously what happens when we vomit.
But let's assume that our food was a good mouthful of food
and when the pre-digestion process has reached its conclusion,
the stomach then begins to contract and pass it towards the far end of the stomach,
where there is a valve called the pylorus,
which regulates its passage into the small intestine.
So let's see where the small intestine is on our live model.
We have reached the pylorus,
which is this thickened area here which lets the food through into the small intestine.
Which starts with a specialised C-shaped bit called the duodenum
and then the folds of small intestines are disposed like this.
The small intestine is the real engine-room of the bowel.
This is where the food is finally broken down into its elementary constituents
and absorbed into the bloodstream.
Food that we eat is essentially alien material.
It comes from other animals, it comes from plants.
Their constituents are not our constituents.
But most foodstuffs are composed of elementary constituents.
Starches, for example, are composed of sugars.
Proteins are composed of building blocks called amino acids.
Fats are composed of elementary building blocks of fatty acids as well.
And in the small bowel is where these are broken down
and then absorbed into the bloodstream.
So let's have a look inside the small intestine on our dissection specimen.
When you look inside the small intestine,
we see the folds and we see some food.
Now after some water, we see more clearly, the folds
One of the points about the folds in the small intestine,
is that these greatly increase its surface area.
And on the folds, in fact if we used a microscope,there are smaller folds
and on the cells that make up those folds, there are even smaller folds called microvilli.
So the area of the small intestines is greatly increased to allow food to be absorbed.
The bowel also has a fairly constant structure throughout.
It has an inner, circular layer of muscle.
And the function of this is to squeeze the food along the gut
and an outer longitudinal layer of muscle which sloshes the food back and forth
and ensures that the enzymes, the digestive enzymes, and food is well mixed.
Also present in our gut is quite a lot of bacteria,
there is probably about one or two kilos of bacteria within our gut
and these actually enter our gut during foetal life.
But these are the right sort of bacteria, because they not only help us digest our food,
they also help us make,
well they also make vitamins that we can't make for ourselves,
which are then absorbed through our gut.
It is said and I don't know who worked this out,
the gut has a nervous system that weighs about the same as our brains.
But obviously, this isn't a nervous system that we are conscious of.
All along the gut there are two nerve plexuses,
which control the muscular movements of our gut
and the movement of food along it.
And obviously, this is very important for the coordinated passage of a meal along the gastrointestinal track.
And when you think now that I can cut the small intestine open, it is wrong,
because as you see, it is really takes a very thick sack away around,
because it is nourished from the back by
first larger and always more smaller arteries and veins.
So, this nourishment from behind
which you see all along this conduit of the large and small intestines,
especially here,
we have to cut off,
in order to have the small intestine in along in its full length.
So listen and have a look for only a little bit of cutting here,
of this piece, I get a long, long piece of small bowel
and I continue this now.
I should just say that we have used the word intestine
and we have used the word bowel,
but these are essentially interchangeable words,
small bowel, small intestines, and sometimes the whole tract is referred to as the gut.
Looking at the small intestine, you see here,
in the opening, a very important opening,
where actually, the juice from the liver through the bile ducts comes.
And this big liver actually is an accessory organ for digestion.
Okay let's see where the liver is on our live model
and here we have a liver that we have prepared earlier.
This is a plastinated liver and it is about the right size to be Dennis's own liver.
The liver is the largest solid organ in the body
and it is tucked up on the right side of your abdominal cavity, but high up under the rib cage.
Well, let's take a large knife and make some thinner slices to look inside.
All pathologists do it, while they do autopsies,
in order to see some metastases of carcinoma for example.
So the cut surface of the liver looks quite normal.
Do you see here?
These are the veins and the arteries where the blood
and our red polymer fixation material is inside.
When you look at the cut surface of the liver, it doesn't look like much.
The liver is a very homogeneous organ,it all looks the same.
But that belies its importance as the main metabolic factory of the body.
This is where all the nutrients, the broken down nutrients from the small bowel, come first
and the liver begins to rebuild those into our own constituents,
so all the good stuff digested from our mouthful of food comes here from the gut,
before it is distributed around the body in the bloodstream.
The liver also amazingly has four complete sets of tubing that go in and out of it.
It has an arterial and a venous supply.
It has a portal blood supply, bringing these nutrients from the gut
and it also has a series of excretory tubes, the bile ducts,
which take the liver's main secretion, the bile, out from the liver and into the small intestine.
Perhaps I should remind us where that is on our live model over here.
The bile enters here and the bile is an important part of the digestive process
because not only does it help us dissolve and absorb fatty substances,
but it is also quite alkaline
and that helps to neutralise the acid that has come through from the stomach
and protect the rest of the small intestine from the effects of stomach acid.
There is also another thing that comes in at the same papilla
and that is the juices from the other main assistant organ of the gut, the pancreas.
The pancreas is a hidden organ.
Here is a pancreas that we have prepared earlier.
Again, it is probably about the right size for Dennis.
It is actually described as having a head, a body and a tail,
this one looks a bit like a sea-horse,
but in fact in the body,
it is horizontal with its head nestled against the curve of the duodenum, there
and the rest of the organ running across the back of the abdominal cavity, behind the stomach.
Now, the pancreas is really a turbo-charged salivary gland.
This is the gland that makes all those special protein enzymes that digest our foodstuffs.
And this is the most dangerous gland in the body
because if these enzymes are let loose on our tissues, they can digest us, as well.
And there is a reason why that can sometimes happen
and we will show you that back over on the dissection specimen.
The pancreas shows its typical glandular tissue and I want to take a cut.
This is a very typical glandular view
and all those tiny little globules give off their juice into a duct,
which actually opens here in the first part of the small intestine, just here the opening
And this has an interesting consequence,
because the opening into the duodenum of the pancreatic duct
is usually a joint opening with the bile ducts.
Now, bile can sometimes give rise to stones,
most people will have heard of gallstones
and these can originate in the gallbladder,
because one of the main jobs of the gallbladder is to concentrate the bile.
Gallstones can sometimes move down the bile ducts
and get stuck in this little papilla.
And if they do, they can stop the pancreatic juices coming out of the pancreas.
And that can cause the pancreas to begin to digest itself.
This is a major medical emergency,it is called acute pancreatitis
and even with modern medical methods,
probably about half of people who get acute pancreatitis die of that condition.
Now we have been talking about so far the so-called exocrine functions of the pancreas.
This is the pancreatic juice that is excreted into the outside world via the gut.
But the pancreas also has another hidden function, which we can show you on monitor here.
Here you can see a histological section of pancreas
and this shows in this area these are the pancreatic cells that secrete those special enzymes that digest the food,
but in the middle here, or at least in this area here, there is a paler area.
And this is, this subsumes the so-called endocrine functions of the pancreas.
Endocrine functions are where a gland secretes something into the bloodstream.
And these little islands here are called the islets of Langerhans,
they were discovered by Paul Langerhans when he was a medical student in the 19th century.
I think they were the days to be doing research,
when you could make a lasting discovery as a medical student.
Part of the reason was because that he was actually using the dyes
that had recently been developed by the chemical industry at that time to stain fabrics
and it turns out that they stain people's tissues pretty well,
as well and allow you to see these things.
These islets of Langerhans are important because one of their functions is to secret the hormone insulin
and insulin is a key metabolic regulator in the body, but especially of blood sugar.
And it is the function of these little islets here,
of which there are many distributed throughout the pancreas
if that fails then the condition of diabetes results, in which blood sugar,
which is the main energy currency of the body,
becomes unregulated and becomes very high.
So, so far we have absorbed the main nutrients from the gut.
But after every good banquet, there needs to be a good cleanup.
And the organs that are mainly responsible for that are the kidneys.
And the kidneys are at the back
and therefore we have to turn the whole organ parcel over.
And the kidneys are protected, in fat
and I have to open this fat capsule to reveal, here, the kidney.
So let's see where the kidneys are on our live model
Again, we have here some plastinated kidneys.
The kidneys are often a bit higher up than people expect.
The blood vessel that supplies them comes off at the bottom of your breastbone,
so the kidneys are at about this level, but at the back of the abdominal cavity,
hidden around the back of the abdominal cavity.
There are also somewhat larger than people often imagine them to be,
but again, this kidney is probably about the right size to be one of Dennis's.
Let's now see how the kidney looks inside.
So I bisect the kidney in two halves.
And there on the cut surface, you see small, red, tiny dots
And this is what they look like.
This little guy is called a glomerulus.
There are about 1 1/2 million of these in each of your kidneys,
so you have about 3 million of these.
And their job is to filter the blood plasma,
which comes in at the edge of the tuft, here across,
a sort of special type of filter-paper that is present within these tufts,
to produce a plasma filtrate in that space
and that means that all the small molecules stay with the fluid and comes out,
but the larger molecules get retained behind.
The point of the kidney is that, whenever we eat something,
we take in excess water, we take in excess salts
and there are toxic breakdown products and waste products
from our own chemical process in the body.
And all the water-soluble substances like that, come out in the kidney
are refined in these tubules and exit the kidney as urine.
The small intestine enters the large intestine,
which runs around the small intestine like the frame of a picture.
Let's see where this is on our live model.
Juliet has here has drawn on the large intestine.
The large intestine starts with a blind ended diverticulum called the cecum,
off which comes the appendix.
It then goes up, across, down, does a final little wiggle
before making its final exit to the outside world.
So let's have a look inside the large intestine on our dissection specimen.
Let's open now, the large intestine,
starting here from the last part of the small intestine.
I go inside, crossing the border between small and large intestines
and crossing a valve
which actually prevents that faeces goes back from the large to the small intestine.
So the large intestine starts up here,
but this part is called the cecum,the blind part.
And attached to this is an appendix
and you will see whether this lady had an appendix or it was removed by an operation.
And indeed, nothing to be seen, the appendix is not there anymore.
Let's open now, and I go this way, up
So the large bowel receives the residue of a meal
that the small bowel wasn't able to absorb.
It has two main functions.
First of all it acts as a storage compartment for faeces
and you can see some faeces here.
These are the indigestible remains of the final meal.
It is useful that this large bowel does act as a storage compartment for faeces,
because this means that we don't have to go to the toilet as often as we eat,
which is helpful.
The other main function of the large bowel ,
it's a sort of compressor and waste facility.
It absorbs water from the semisolid material that comes in,
or from the rather liquid material, in fact, that comes in from the small bowel
and changes it into the rather harder material that finally comes out at the far end.
When the food moves round the large intestine,
the final part of the gastrointestinal tract, is known as the anus.
And I'm not going over to Dennis to demonstrate that,
but the anus is normally a fairly constricted ring
and obviously, this has to dilate up and close down,
dilate up and close down as the food makes its final exit from our body.
And this actually causes certain problems in the anus.
The anus as it dilates up and can actually develop a fissure in it
and the anal fissure can be very painful
and they can be quite difficult to heal up,
because the anus isn't something you can stop using while they get better.
And sometimes they can close up
leaving a little communication between the outside body and inside the anus.
And this is known as the fistula in-ano.
This is a condition that has caused a lot of misery during human history
and one of the people who suffered from it was Louis XIV.
And this had, actually, quite a happy consequence for one of his doctors,
because one of his doctors was able to incise the fistula with a small operation,
which is what is still done today, without which it wouldn't cure,
but with which they are actually are cured quite quickly.
And Louis XIV was so grateful to this doctor that he made him a life baron.
Now, fortunately that doesn't happen so often these days,
because doctors tend to get taken to court in a different way.
But anyway, times move on
and so finally to the remains of the meal that we have been discussing.
The end of the large intestine is the anus.
The anus from the outside.
And here, a kind of circular muscle opens at best only once a day, leaving the faeces out.
And in this way, we arrive at the end of our journey through the whole intestinal tract.
The anus is the end, as the tongue was the mouth at the beginning.
And this is the right time to invite you for questions. Please.
If someone were to have an ulcer,
how would that look, and what exactly is an ulcer?
An ulcer, actually, would either appear in the lining of the stomach
or in the beginning of the small intestine.
That's right, the definition of an ulcer is that the epithelial lining
the lining layer of the area,is actually destroyed.
And that give access of the, for example in the stomach,
of the stomach acid to the underlying tissues.
And that means that the acid and the digestive hormones can actually erode a hole through the stomach
and if it goes the whole way, it can actually make a hole
from the stomach into the peritoneal cavity which is a cause of peritonitis
inflammation of the peritoneal cavity.
You mentioned that the large appendum of the stomach can accumulate fat.
How many grams or kilos of fat can it amass?
It is very different in different people actually.
Some people have quite a small greater omentum, as in fact this lady did.
In some people it can actually measure many kilos, 5,6,7,8 kilos in large..
In America: 20 kilos is possible!
We hear today of people having their stomachs stapled.
What exactly is done when somebody has their stomach stapled?
Well, the idea of a stomach stabling operation, or fundoplasty,
is to pinch off part of the stomach,
so the feeling of being full is induced sooner than it is
if your stomach is allowed to expand to the full thing.
And this is something that in many cases helps very obese people not to eat too much,
because they feel full sooner, and it helps them to lose weight.
Last question now please.
Yea, I have a question about acid reflux.
There are so many medications on the market now for acid reflux
because of the food you eat, the medicines you take or due to sinus infections.
Can you talk a little bit about that?
This is a very complicated issue.
Actually, my doctoral thesis dealt with that.
First of all we have an angulation of the oesophagus in the upper part of the stomach.
And depending on this angulation,
it influences the sphincter the circle muscle here,
the opening at the end of the oesophagus.
Moreover, the pressure, the inter-abdominal pressure is very important.
So whether you sleep flat, or you sleep a little upright,
whether you have a large obesity is a big inter-abdominal pressure or not,
it is very important.
To cure the feeling once the acid goes up, it's already too late,
but it only eases the symptoms, but doesn't cure.
There are three foods that are particularly associated with reflux
because they tend to delay emptying of the stomach.
And they are wine, or alcohol,
coffee and chocolate.
So it is normally quite a bad idea to do what we all do after a dinner party.
Which have a glass of wine with the party,
have a coffee afterwards and some chocolate and then go to bed.
Good to know.
As I promised you in the beginning,
now I will unravel this woman's gut from the tongue to the anus.
Therefore I need assistance.
And here, there is the pharynx.
And here is the stomach,
OK, would you come over here.
Some small intestine,
please go ahead here.
And here starts the large intestine.
And would you come over here?
And over here
and actually, this is what I promised you:
1, 2, 3, 4, 5, 6, 7 metres of intestinal tract.
Transcript: bigbreaths Synchro: PyrSos_