Mhm.
In this program we will examine discuss
the microscopic and the light microscopic appearance of
selected portions of the gi tract
objectives for this program may be found in the accompanying
study guide.
This cross sectional diagram
Shows the four basic layers
of the gi tract
First the mucosa,
the sub mucosa,
muscular as external,
and the cirrhosis
variations on this basic plan can help
identify the specific area of the gi tract.
Understudy.
This drawing is divided Into two sections.
The left side
represents the
characteristic structure of the small intestine.
The right side represents a section of the
colon beginning on
the Luminal side.
We see the covering epithelium which
may be either stratified squamous or
simple kilometer epithelium depending upon
the area
immediately underline the
epithelium.
We have a loose connective tissue layer
termed the lamb inappropriate.
The next layer contains smooth
muscle and it's called the
muscular eras mucosa.
These three layers together
I called the mucosa.
Next there's a layer of connective tissue,
the sub mucosa and within the sub
mucosa there's a group of
nerve cells and bundles of nerve fibers
termed the mice ners
plexus.
The next layer is usually made up of
smooth muscle but may under
certain conditions be made up of skeletal
muscle.
This layer is termed the
muscular rose X.
Turn up and generally
consists of an inner circular
and an outer longitudinal layer.
There is a group of nerve cells and
fibers located within the muscular sex terna
termed the our box
plexus.
Both the meisters and our
box plexus is formed the
intrinsic nerve supply of the
intestinal wall
immediately outside of the
must get rs external.
We see a layer of connective tissue
with a covering mesophyll idea layer.
This is termed the cirrhosis.
On the left side.
We see mucosal glands
and projections of the
lamb inappropriate characteristic of the small
intestine.
These projections are termed Valli.
In addition,
we see sub mucosal folds,
term clicky circular areas.
We also see large ducks
penetrating the wall
like those coming from the pancreas.
Then after their secretions into the gi
tract,
we also see sub mucosal glands
characteristic of the duodenum.
The right side represents a
section of the colon with the
lymphatic tissue,
and there are no.
They live.
Now let's look at a series of slides
of the gi tract beginning with the lip.
This is the all side,
all the lip.
We see a thickened
non carotene eyes,
stratified squamous epithelium.
As we move around
the edge
of the lip,
we see the transition at this point
to the carotene.
Ized,
stratified squamous epithelium
with numerous hair follicles,
and associated sebaceous glands.
In this area
we see numerous mucous
glands,
as well as the
skeletal muscle fibers
present within the
obituaries Oris muscle.
As we can see in this
area here.
Well,
next demonstrate three types of pili
with three different slides of the tongue.
The first slide shows the fill,
a form capelli.
On the surface we see
the carrot,
ionized,
stratified squamous epithelium
with an underlying lamb inappropriate.
We see that the lamb inappropriate is thrown
into basil folds to
reflect it as surface
projections.
These folds are
called happily.
There are elevations are both connective tissue and the
epithelium.
There may be smaller projections,
connective tissue in the epithelium,
resulting in secondary,
properly on
the surface of the epithelium.
We could see threadlike
projections of the stratified squamous epithelium,
which contains a small core of connective tissue.
These projections are termed the fill a
form happily
the years.
Capelli do not
contain taste buds.
We can also now see
skeletal muscle
fibers arranged in a very
characteristic criss cross
pattern within the substance of the tongue.
On the next slide we see foliate
papillae.
They are more common in certain rodents than man,
but do resemble the fungi form
Papillion,
man.
The foliate capelli,
our dome shaped
and are more dome shaped than the fill,
a form papillae,
note that the secondary
projections of connective tissue
are not reflected by the covering
epithelium.
Therefore,
the vascular supply is brought in
very close contact to the
outside surface.
This creates a pinkish appearance in the living
state.
In the substance of the tongue,
we see that there are
large groups of syria's
glands,
which are termed the glands of von
Ebner.
On the lateral border
of the people,
we see the lighter stained areas
which are the taste buds.
Mhm.
Now in this field
we see first the
opening
all of the taste buds,
which is called the taste poor.
We see that there are two general cell
types within the taste buds.
First there would be the
supporting
sustain tacular cells which
contain lightly stained nuclei
and are arranged like staves of a barrel,
around the taste poor
between the substance of the cells.
Our darker stained
neural epithelial cells.
On the next slide we'll examine the validate
happily.
On our low power objective,
we see that the valid happily
tends to be recessed below the surface of the town,
therefore they frequently appear to be isolated.
It is important to remember that they do
open to the surface of the tongue.
Note the general characteristics of the
tongue with the covering
epithelium,
the underlying connective tissue,
skeletal muscle
and the serious glands
notice on the lateral surface
of the validate.
Hopefully the
taste buds
as we continue down the gi tract,
we will next Examine The Upper 1/3 of the
Esophagus.
This is a macroscopic cross sectional
view of the esophagus.
If we began on the Luminal
side,
we can see first the
epithelium,
the underlying lamb inappropriate,
The sub mucosa
and the outer more darkly
sustained muscular areas.
External.
We're on our low power objective.
On the microscope.
Beginning on the Luminal side,
we see the covering non
carotene.
Ized stratified squamous
epithelium.
Next we see the connective tissue layer,
the lamb inappropriate,
followed by a smooth muscle layer
termed the muscular as
mucosa.
Outside of the muscular S.
Mucosa,
we see the sub mucosa,
another connective tissue layer containing
blood vessels.
Yeah,
and connective tissue fibers.
As we move to the
muscularity external,
we see that the
muscle and skeletal muscle
with the characteristic
peripheral
nuclei the presence of
skeletal muscle and the muscular sex turner is
evidence that this is the upper
1/3 of the Esophagus.
Next we will examine the lower 1/3 of the
esophagus.
As we began on the Luminal side,
we see again a non
carotene.
Ized stratified squamous epithelium
with its underlying lamb
inappropriate.
We see
below that the muscular
areas,
mucosa
and a very thin
underlying sub mucosal connective
tissue layer.
As we move to the muscular is
external,
we see that it consists of an inner
circular layer
and an outer longitudinal
layer of smooth muscle.
On high power.
We can now see a junction all area
between the inner circular
seen in cross section
and the outer longitudinal
layers of smooth muscle fibers During
contrast to the skeletal muscle fibers
of the Upper 1/3 of the Esophagus.
To distinguish between the upper third,
one third and the lower third of the
esophagus.
One must examine the type of muscle
present within the muscular as external.
There is skeletal muscle present in the upper part,
A blending of the two types in the middle
3rd and a predominance of smooth
muscle in the
lower part.
As we continue,
we will examine the junction all area between the
esophagus and the stomach.
On our low power objective we can see
the abrupt transition between
the esophagus
and the stomach.
We can see the stratified squamous epithelium,
non character knives to the esophagus
and in this area
the simple
kilometer epithelial lining of the
cardiac portion of the stomach.
Note the presence of glands
within the lamb inappropriate of the
stomach.
These may be either simple
or compound tubular types of lands and
generally function to secrete
mucus.
They have little impact on the total
function of the stomach.
The following slide is from the funders of the
stomach.
This is a microscopic view We
see first what appears to be a very
thick
epithelium.
In fact this area consists of glandular
in folding from the surface.
We can also see large
sub mucosal folds which in the stomach
are termed Rudy.
To the outside we can
see the muscular us
external.
And before proceeding to the microscopic study of this
slide we will examine a diagram
are the characteristic gastric
glands.
This diagram shows the gastric
gland which is divided into four
basic parts.
Beginning on the surface
we see the covering
service epithelial cells and
the imaginations
of the apathy ideal surface which is termed the
pit.
Second we see an area
it contains
the isthmus.
It has pink staining parietal
cells
and the surface epithelial cells.
Below this we
see the neck of the gland,
which again contains the ready
stained parietal cells
and the
mucus.
Next cells
in the deepest portion of the gland
we see the base of the gland containing again
parietal cells
and the base of filic zima
genic cells.
We are now on the low power objectives with the
funding of the stomach.
Take special note of the very
thick mucosa which
contains numerous
glands
changing to her high power.
On the surface
we see the surface epithelial
cells
and the pit.
Below this we see
several piggy stain cells
term the parietal cells
that will in combination with the
surface epithelial cells
comprise the isthmus.
Below this we
begin to pick up the parietal cells
and more darkly stained
cells which are termed the mucus Next
cells
This area would be the neck of the
gland.
In the deeper areas
we see basa filic cells
two term the zimet and cells
with occasional parietal cells
immediately below
the glands.
We see a very thin
muscular mucosa
and then the underlying
seven mucosa
note in this area,
the presence of fibers of my
sinners plexus.
To the outside,
we can now begin to see beginning of
the muscular sx turn up
containing smooth muscle
and in this case showing the characteristic inner
circular
and to the outside
the outer longitudinal layers.
In some places within the
stomach,
you may see an additional circular
layer.
Okay,
note in this area the
presence of fibers of the our
box plexus.
We will continue our examination of the gi
tract with the polaris of the stomach
On our 10 x.
objective.
Take note of the very deep
and elongate pits
within the polaris.
The pets are lined by surface
epithelial cells.
Note that these extend down at least
halfway through the mucosal
layer.
In the basal area,
the glands become coiled and contain
mucus producing cells.
Below this we see
the musket,
irish mucosa and the
underlying sub mucosa.
The muscular s,
external is cut
in an oblique section,
but in this area
one can see nerve fibers and cells
of the our box plexus,
again noting the nerve fibers
and the bluish staining ganglion
cells.
Mhm.
Now in review
there are two general features which serve to
distinguish the polaris from the funders
portion of the stomach,
first very deep
pit in the polaris
compares with a very shallow pit in the
fungus.
Secondly,
the homogeneous cell types
present within the polaris
contrast with the heterogeneous cells
lining the funding glands.
The next slide will show the first
portion of the small intestine called the
duodenum.
We're looking at a macroscopic view
and beginning on the Luminal side,
one can see first the presence of
Valli or
folds of the lamb inappropriate.
These light stained patches
within the sub mucosa,
our glands and to the
outside we see a thick,
muscular as external.
On our scan objective,
we can see the characteristic Valli
or folds of lamb inappropriate.
With some of the valley cut in cross
section.
Note the presence of the
mucosal glands
and a rather conspicuous mucosa
In the 70 Koza,
no the presence of the light staining
mucous producing glands,
which are termed Brunner's glands.
Again in the
muscular wrist X.
Turn up,
we can see the inner circular
and the outer longitude and the layers.
Note the presence of several lymphatic
Nigel's which can be
present either in the mucosa
or the sub mucosa.
The amount of lymphatic tissue present within the connective
tissue tends
to increase as one moves down the gi
tract.
Changing to our 10 X.
Objective
note that as the Valli
project above the surface there are
small glandular
imaginations
which project into the lamb
inappropriate.
And these mucosal glands
are termed the crips of liberty.
Changing now to our high power objective.
As we began
to examine the surface
epithelium,
we see the presence of first goblet cells
and these are not present in the stomach and are unique
to the small and large intestine.
Note the presence of the brush border
on the service of the epithelial cells,
the lamb inappropriate within the
Valli contained in this case
several plasma cells and other
lymphoid cells
within the core.
one can see very small emphatic
channels
which are termed lacked eels.
To review this section can be
identified as small intestine because of the
presence of Valli
and goblet cells.
To distinguish the duodenum
from the other portions of the small
intestine.
You must identify the
sub mucosal Brunner's
glands which are not present
in any other part of the gi tract.
Let's now examine the next section of the small intestine,
the Juno,
this is on low power with an asian
e stain.
We again see both Valli
and the presence of individual
goblet cells
to all characteristic of the small intestine,
changing to our high power
as we move deeper
into the glandular portion of the crips of labor
coun
we see at the extreme
basil portion
of the land,
the presence of reddish cells.
These cells are termed pan.
It sells
the cells such as the Ar Gentlemen
cells are also
present but will not show with a
standard Hema toxin and es and
stain.
Now in review we
see the Valli.
It's a characteristic of the small
intestine.
We do not see sub mucosal
Brunner's glands.
This fact will serve to distinguish the june um
from the duodenum.
Although the number and the shape
of the village,
I will change gradually from the jejune
um to the ilium.
You will not be required to distinguish between the
june um and the ilium.
We will now examine the structure of the colon
or large intestine.
On the microscopic view,
we see the epithelial surface
and the dark stained area
which contains the sub mucosa
and the muscular as external.
Notice that the colon does not contain
ville I as the small intestine does
but does contain
sub mucosal folds.
On high power.
We see first the surface
epithelial cells and begin to then pick up
presence of goblet cells.
These are indicated here
this combination of godless cells but
novell I tells you it is the colon.
Below this we see the
muscular as mucosa
and a relatively thin
sub mucosa.
Yes,
you may see frequently within the
mucosa and the sub mucosa,
lymphatic modules.
Externally we see
the muscular is external
with a characteristic inner circular
and outer longitudinal
arrangement.
Note the presence of both
cells and fibers of our box
plexus.
Changing back to our scan objective
note
that the outer circular muscle
is thickened into bands
that are known as Tenia coli.
Will now examine a cross section of the appendix
beginning on the Luminal side.
Yeah,
we see first goblet cells
and no Valli.
This finding is compatible with the distinguishing
characteristics in the colon.
Within the lamb inappropriate.
We see a very heavy invasion of lymphocytic
cells and a
conspicuous muscular as
mucosa.
Okay,
and the sub mucosa
we again see several modular masses
of lymphatic tissue.
And on the outside
we see a rather
than muscular eras
external.
Again,
we have an inner circular
and an outer longitudinal
arrangement of smooth muscle cells.
So in review the
appendix has the structure
of the colon,
but it's always heavily
infiltrated with
lymphoid cells.
Therefore,
the appendix can be considered as a
council.
This mask
within the lumen is partially
digested material.
On the last slide we'll examine the
rectal anal canal.
Yeah,
in the rectum we continue to have the
glands,
our cribs,
nobody broken with no
Valli and a
large number from God,
but cells,
this finding is consistent with the
morphology of the colon.
However,
there are no 10ia coli in
the rectum
due to the oblique section
of this slide,
the outer longitudinal and
the inner circular layers of the muscular s.
External do not show.
As we
move
toward the anal canal.
We see that in the anal canal there is
a transition from a simple kilometer
epithelium to a non
carotene.
Ized,
stratified squamous epithelium.
There is not a sharply
defined muscular as mucosa,
and therefore the separation
between the mucosa and the
sub mucosa is not clear
due to the heavy concentration of the lymphatic
tissue within the mucosal
and sub mucosal areas.
These features will help to
differentiate this part of the anal canal
from the esophagus.
Now,
as we move down
the anal canal,
there will be a transition
from the non character in Ized
stratified squamous epithelium to the carotene.
Ized empathy Veum
as seen in these areas,
and this will become continuous then with the
skin thin skin.
At this point
this area contains
para follicles
and sebaceous glands,
all of which are consistent with the
structure of thin skin.
This completes the tape on the GI tract.