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A HISTOLGQC STUDY 0F THE BOVINE'ABOMASUM

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Thesis for the Begree of M. S.

MECHIGA‘N STATE LENWERSETY .
ROBERT MIMMONS

1969

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A HISTOLOGIC STUDY OF THE BOVINE ABOMASUM

By

9!.
Robert A) Simmons

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirement:
for the degree or

MASTER OF SCIENCE
Department of Anatomy

1969

ACKNOWLEDGEMENTB

The author wishes to eXpress his sincere gratitude
to Dr. A. U. Stinson for his most helpful guidance through-
out the course of this investigation.

Thanks also to Drs. Smith and Carrow for their
constructive criticism and helpful suggestions for improv-
ing the manuscript. Thanks also to Dr. Calhoun for helpful
suggestions throughout the course of this work.

Special thanks to Dr. Bruce Walker and his staff
for the use of material and facilities in the Department of

Anatomy.

‘11

TABLE OE‘OONTENTS

INTRODUCTION ---------------------- 1
must OF-LITERATURE ------------------ 2
A EarlyDescription - ---------------- 2
The Abomasal Mucosa ---------------- 1
Innervation -------------------- 6
Developmental Anatomy --------------- 7
MATERIALS AND.METHOD8 ------------------ 9
RESULTS AND DISCUSSION ----------------- ll
Glandular Regions of the Abomasun ---------- 12
Cardiac Gland Region ------------- 12
Peptio.Gland Region -------------- 13
Intermediate Zone --------------- l4

Pyloric Gland Region. ------------- 14

Junction of Pylorus and Duodenum ------- 15

Mucosal Epithelium ----------------- 16
Surface Mucous Cells ------------- l6

Mucous Neck Cells --------------- l7

Parietal Cells 7 --------------- 18

Chief Cells- - - --------------- 20
Argentaffin Cells- - ------------- 21

Globule Leukocyte --------------- 23

Lamina Propria ------------------- 26
Muscularis Mucosaey ---------------- 28
Suhmucosa --------------------- 29
Muscularis Externa ----------------- 30

111

iv.

Serosa - - - - — - - — - - - - - _ - - - - - 5 - - 32
SUMMARI ------------------------ 3}
LITERATURE CITED -------------------- 37

FIGURES 4 ----------------------- 41

LIST OF FIGURES

Figure, Page
I l. Abomasums showing levels at which samples were
taken ----------------------- 42

2. Variations in thickness of the mucosa ------- 43
3. Variations in thickness of the muscularis mucosae- 44
4.. Variations in thickness of muscularis externa- - - 45
5.. Variations in the number of parietal cells - - - - 46
6. Variations in the number of chief cells ----- 47
7.. Variations in the number of argentaffin oells- - - 48
8. Variations in the number of globule leukocytes - - 49

9. Surface view of the lining of the abomasum in the

peptic region ------------------- 50
10. Surface view of the lining of the abomasum in the

pyloric region - - - - -------------- 51
11. Wall of the peptic region at level A2 ------- 52
12. Wall of the intermediate zone at level A7 ----- 53
13. Wall of the pyloric region at level A9 ------ 54
14. Wall of the pyloric region at level A10 ------ 55
15. Longitudinal section of the Junction of the,

pylorus and the duodenum ------------- 56
16. Longitudinal section of the Junction of the

of the omasum and abomasum -------- 5- - - - 57
17. Upper third of the peptic mucosa -------- -‘58
18. Middle third of the peptic mucosa --------- 59
19. Lower third of the peptic mucosa --------- 60

20. Pyloric mucosa showing mamillated arrangement- - - 61

21. The peptic mucosa ----------------- 62
22. Neck region of the gastric glands --------- 63
23. Two mitotic figures among the cells which line
the fovealae ------------------- 64
24. The peptic mucosa at level A4 showing a relative
high number of parietal and chief cells ------ 65

V

vi

Figure "Page

25. The peptic mucosa at level A7 showing long

fovealae and relatively fewer parietal and

chief cells - - .................. 66
26. The glands of the_intermediate zone ------- -67

27. Distribution of argentaffin cells showing a high
concentration in the lower half of the peptic

mucosa ---------------------- 68
28. A more even distribution of argentaffin cells as

seen in the pyloric mucosa -------- - - - - 69
29. High power view of argentaffin cells ------- 7O

30. Globule leukocytes among the fovealar cells- - - - 71

31. a portion of mucosal plexus ------------ 72
32. High power view of the peptic mucosa ------- 73
33. Reticular network in the lamina propria ------ 74

34.. A portion of the submucosal plexus of Meissner - - 75

35. Silver impregnation of a portion of the submucosal
p10xu9 .................. - - u - 76
35. A.portion of the myenteric plexus of Auerbach- - - 77

37. Reticular fibers surrounding smooth muscle cells
in the muscularis externa ------- - - - -»--- 78

INTRODUCTION

The upper digestive tract of the ruminant has been
under investigation for some time. Because of their unique
function and design, attention has been focused on the upper
three chambers of the ruminant stomach. Much less informa-
tion is available concerning the glandular portion,_the abo-
masum.

The results of recent studies of the abomasum in
sheep and goats have been published. Similar information
about this organ in cattle is more limited.

The purpose of this study is, first, to describe
the general microscopic structure of the entire abomasum;
secondly, quantitative measurements of the histologic
changes along the greater curvature are presented to serve
as a key to the overall topography of the organ.

It is hoped that the information presented in the
following pages will provide the histologic framework
necessary for future physiologic and pathologic inves-

tigations of the bovine abomasum.

REVIEW OF LITERATURE

A thorough review of the literature revealed that a
moderate amount of information.concerning the ruminant
abomasum was available, while information specifically.
concerned with the abomasum in cattle was limited. De-
scriptions of the glandular stomach in.monogastric animals

were available for comparison.

Early Description”
Ellenberger.(1827,,1884),according to Oppel.(l896),

recognized the division of the abomasum into fundic and
pyloric regions. In the fundic region he observed from
thirteen to sixteen large folds in the mucous membrane
in the three domestic animals he studied. He described
the branching of the glands from the fovealae and the re-
lationship of the cells in the glands of the fundic region.
The recognition.of the cell types in the abomasal glands
dates from the research of Heidenhain (1870),,who described
the peptic cells of the sheep abomasal glands, and from
the description by Rollett (1871), as recorded by Oppel
(1896), of both the parietal and the peptic cells in the
abomasum. Pauli (1884), according to Oppel (1896), was
the first to report on the mucous nature of the pyloric
glands.“

Brugnone (1811), as cited by Oppel (1896), commented
early on the abundance of lymphoid tissue in the ruminant
abomasum. Ellenberger (1827,.1884) added that follicles of

2

3
lymphoid tissue were more abundant in the pyloric than in

the fundic region. He also reported that the muscularis
mucosae was stronger in the pyloric region.

There was some disagreement in the older literature
as to the existence of a cardiac gland region in the rum-
inant abomasum. Cordier (1893) described an abrupt change
in the lining epithelium from the omasum to the abomasum
in a wide variety of ruminants. Ellenberger (1827,.1884)
contended that cardiac glands were not demonstrable at
this Junction in the cow. Later, according to Bensley (1910),
Haane (1905) described a transition zone of cardiac glands A
at the omaso-abomasal Junction in the ox, sheep, and goat.
and Frohlich (1907) found cardiac glands present in all
domestic animals. The identity of these glands in various
animals was finally established by Bensley (1910) and their
presence in the ruminant has been confirmed in more recent-

studies (Hill, 1951; Sommerville, 1956).

The Abqgasal Mucosa

Most of the available literature is concerned with
the glands of the mucous membrane. Tehver (1939) described
and demonstrated photographically, the shape, approximate
dimensions, relative or total number, and mutual connec-
tions of the micro-relief elements of the gastrointestional
tube of the horse, ox, sheep, pig, dog, and cat. The micro-
relief elements of the stomach (fovealae, interfovealar septa,

and gastric villi) differ greatly in the various animals.

4

Hill (1951) studied the glands in the abomasal mucosa
in three goats. Three types of glands were observed and on
the basis of their distribution the abomasum was divided
into cardiac, peptic, and pyloric regions. In one goat
an intermediate zone (Billenkamp, 1929) was observed.
Peptic and parietal cells were counted and the distribu-
tion of argentaffin cells was determined.. The presence of
’arounded cell containing a varying number of eosinophilic
granules“ was noted.

Sommerville (l956)made a similar study of the abo-
masal mucosa in three sheep. Peptic and parietal cells
were counted and the distribution of argentaffin cells was
described in one sheep.

Kondo (1966) contributed a quantitative study of some
of the histologic aspects of the fundic mucosa in cattle
and various other domestic animals. Measurements of the
thickness of the mucosa and the lengths of the glands
were made in various areas of the fundic region. Paren-
chymal cell ratios and the shape of the glands were also
noted. In a second study published in the same year, Kondo
et al. (1966) described the distribution of the three main
cell types in the fundic stomach of the same animals. The
glands were divided into upper, middle, and lower portions
and cell counts were made at each level..

Hill (1965), in a chapter on gastric gland secretion,
observed that peptic cells are found in all stages of

activity in the abomasum. He also observed frequent chronic

5
inflammatory changes in the mucosa, evidenced by excess
mucous secretion, lymphoid infiltration, and the presence
of the globule leukocyte.

The globule leukocyte ("Schollenleukocyten") was
first described by Weill (1919) in the digestive mucosa
of the dog, cat, mouse, rabbit, and pig. In these animals
they were more numerous in the intestinal mucosa than in
that of the stomach. He regarded the cells to be of lym-
phocyte origin and their globules as endogenous secretory
granules.

Keasbey (1923) presented a comprehensive report on
the globule leukocyte as seen in the alimentary mucosa of
nine sheep and two cows. They were observed to be a con-
stant feature of the abomasal mucosa in healthy individuals.
She conducted numerous experiments to determine how the
globules might compare with erythrocytic material. She
suggested that the cell might in some way be related to
the degeneration of subepithelial capillaries following
a lymphocyte infiltration.

Recent studies relate the presence of the globule
leukocyte to exogenous factors. Sommerville (1956)
examined the abomasal mucosa of fifty-three sheep for the
presence of the globule leukocyte. The presence of this cell
type was correlated with the number of lymphocyte infil-
trations and a relationship between the presence of the
globule leukocyte and a nematode infestation was suggested.

Kirkman (1950) found that bladder worm infestation in the

6
rat elicited the appearance of globule leukocytes in the
transitional epithelium of the urinary bladder. Whur (1966)
further explored this relationship by examining the gastro-
intestinal tract for globule leukocytes in nematode-infested
and nematode-free sheep and rats. Globule leukocytes were
essentially absent in worm-free animals and their subse—
quent appearance was clearly related to nematode infesta-
tion in both number and location of the cells. Likewise,
the appearance of the globule leukocytes coincided with

the time of self-cure.

W _

Marschall (1910), according to Habel (1956), demon-
strated the ganglia of the myenteric and submucosal plexuses
in the ruminant stomach. He stated that these were most
abundant in the reticulum, cardia, and pylorus. Sokolowa
(1931) studied the structure of the intramural ganglia in
the digestive tract of cattle using the Bielschowsky-Gros
method. He described a general distribution of Dogiel type
II cells in the abomasum in addition to the type I cells
common to the rest of the tract. Kolossow (1933) also
noted the presence of large primitive cells in the ganglia of
the abomasum in his study of morphology and degeneration
in the digestive tract of sheep.

Habel (1956) studied the innervation of the ruminant
stomach in sheep and goats. Using the Bielschowsky-Gros
method, he demonstrated extensive myenteric plexuses

in all parts of the stomach. Again, of the larger and

7
smaller ganglion cells he described throughout the stomach,
the abomasum had a predominance of the larger cells.
The ganglia were largest and most numerous in the pyloric
antrum. The submucosal plexus with its ganglia was seen
to extend through the muscularis mucosae into the lamina
propria and small groups of ganglion cells were often
seen close to the glandular epithelium.

Morrison and Habel (1964) carried out a quantitative
study of the relative number of cells associated with
degenerated vagal endings in various parts of the stomachs
of four sheep to determine whether these regions differed
in the percentage of cells with vagal endings. Included
in the study were samples from the lesser and greater
curvatures of the abomasum. The samples taken from these
two locations were seen to have the lowest percentage of
ganglion cells with vagal endings of all those included
in the study.

govelgpmentgl Anatomy

Developmental studies have focused on the mucosa and
in particular the formation of the fundic glands and the
appearance of their cellular components.

.In an early attempt to correlate the differentiation
of certain cells with the onset of functional activity,
Sewall (1878), studied the gastric epithelium in sheep
embrypl.. The “ovoid cells" (parietal) were observed to
differentiate much earlier than the ”central cells" (chief).

.‘

The appearance of the ”central cells" was correlated.with

8
the start of proteolytic activity. Also included in this
study was a description of the development of the mucosal
folds as well as formation of the glands.

Sewall's findings of gastric development in sheep
were partially confirmed by Hill(l956), at least in the
former's description of the development of the mucosal
folds and the formation of the glands. Hill found peptic
cells containing zymogen granules present in
early fetal life but he observed that parietal cells did
not become numerous until after birth. Abomasal contents
were found to contain proteolytic enzymes during late fetal
life but showed no acidic reaction until after birth.

Kapp (1967) reported on the development of the fundic
mucosa in domestic cattle. Changes in mucosal thickness,
fovealar and glandular length were noted. The number
and position of parietal and chief cells were recorded
during the fetal and neonatal periods..

Tamate et al..(l963) studied the effect of diet on
the development of the fundic glands on the abomasum of
calves.

Finally, Hill (1961), compiled a comprehensive
review of the literature dealing with various aspects of

the ruminant abomasum including a section on its histology.

MATERIALS AND METHODS

Material from the abomasums of eight slaughterhouse
cows was studied for the histologic structure. The ani-
mals were killed by the routine slaughterhouse procedure
of stunning and exsanguination. The tissues were placed
in the fixative within twenty to twenty five-minutes of
death. BlockS‘ of tissue were taken from scattered places
in the abomasum, washed in warm saline, and placed in the
following fixativess' Bouin's fluid (Gridley, 1960), 10%
formalin (Gridley, 1960),,and Holly's Zenker-formalin
(Galigher and Kozloff, 1964). ‘

The greater curvature was identified by the attach-
ment of the greater omentum and a strip along this border
was removed from each of three abomasums and placed in
the fixatives. Following fixation, blocks were cut at
the following levels: proximal peptic, middle peptic,
peptic-pyloric or intermediate zone, proximal pyloric,
middle pyloric, and distal pyloric regions. In addition,
blocks of tissue were taken at the omaso-abomasal and
abomaso-duodenal Junctions. The approximate levels of
these blocks are shown in Figure 1.

All tissues remained in the fixatives the optimum
time for each and were washed as necessary. Dehydration
and clearing were accomplished in graduated changes of
tetrahydrofuran. Infiltration with Paraplast was carried
out under a vacuum of 20mm/Hg at 56-58°C.for two hours

before the tissues were embedded.

9

10

All blocks were sectioned at seven microns and the
following stains were employed: hematoxylin and eosin
(Gridley, 1960), Crossmon’s modification of Mallory's
triple stain (Crossmon, 1937),.Bodian's Protargol method
(Dawson and Barnett, 1944; Gridley, 1960), and Southgate's
mucicarmine (Carleton and Leach, 1947).

Globule leukocytes, parietal, and chief cells were
counted at the representative levels along the three
greater curvatures. Argentaffin cells were counted in two
abomasums. A,5 mm square grid divided into one hundred .05 mm
square divisions was used for the counts. Globule leuk-
ocytes were counted in twenty fields at intervals along
each section at 430x magnification. Parietal and chief
cells were counted in five fields at 150x using one-half
of the grid. Finally, argentaffin cells were counted in
ten fields at 150x.

The thicknesses of the mucosa (to the muscularis mu-
cosae), muscularis mucosae, and muscularis externa were
measured in representative sections using an ocular
micrometer with .1 mm divisions.

All photomicrographs were taken using a B;& L Model B

photomicroscopic camera and panatomic x film.

RESULTS AND DISCUSSION

The abomasum is the fourth chamber of the ruminant
stomach extending from its proximal Junction with the omasum
distally to the small intestine. It is the glandular
portion of the ruminant stomach and is similar in structure
and function to the simple stomach of monogastric animals.
The abomasum is divided into a thin-walled,.exPanded body
or peptic portion, and a slightly constricted, more muscular,
pyloric portion. There is no demonstrable fundus and the
whole may be described as an elongated sac.. The average
length along the greater curvature in three animals was
50 centimeters (Figure 1).

The wall of the abomasum is composed of four layers:

a glandular mucous membrane, a supporting submucous layer,
a muscularis externa, and a serosal covering.

The mucous membrane of the peptic region is thrown
into a dozen or so permanent longitudinal folds which
gradually flatten towards the pyloric region. The distal
abomasum is characterized by rugae similar to those de—
scribed in the stomach of non-ruminants. In the fresh
specimen, the reddish-brown peptic mucosa is easily
distinguished from the pyloric mucosa which is grayish-
yellow.

The mucosa shows regional variations in thickness.

Its thickness (to the muscularis mucosae) was measured
at various intervals along the greater curvature in three

animals (Figure 2). Photographs of representative areas

11

12

are shown in Figures 11, 12, 13, and 14. Except for a
slight thickening at the cardiac region, the peptic mucosa
is uniformly thin throughout its length. The pyloric mucosa,
however, shows a progressive and sharp increase towards

the pylorus. The mucous membrane is thickest at the pylorus
(Figure 15). Such changes in mucosal thickness are typical
of the ruminant abomasum (Sisson and Grossman, 1964) as

well as the non-ruminant stomach (Berger, 1934; Kondo, 1966).

Glandular Regions 92 thg Abomasum
0n the basis of the histology, four regions are
distinguished in the bovine abomasum: a narrow cardiac
gland zone, a wide peptic region, an intermediate area

of transition, and a pyloric region.

cardiac gland Region

At the omaso-abomasal Junction, the mucous membrane
is characterized by simple, branched, tubular glands
formed almost exclusively by mucous cells. The existence
of a cardiac zone in ruminants has been questioned in
the literature (Ellenberger, 1884; Bensley, 1910; Elias,n
1946) but it appears that at least a narrow zone of mucous
glands is present at the omaso-abomasal orifice (Hill,
1951; Sommerville, 1956; Sisson and Grossman, 1964).
The width of the cardiac gland region in three of the
animals included in this study was 1.6 mm, .94 mm, and 1.4 mm.
The presence of mucigen droplets in the cardiac gland

cells was demonstrated with Southgate's mucicarmine (Figure.

13
16). Some parietal cells are present and these (along
with chief cells) gradually increase in number to become
the predominant cell type moving from the omaso—abomasal

orifice.

Peptic Gland Region

The mucous cells of the cardiac glands are replaced
by parietal and chief cells in the peptic region. Since
there is no well-defined fundus in the bovine abomasum
and because the distribution of the chief or peptic cells
is well-defined, the proximal 60% or so of the abomasum
will be called the peptic region. Likewise, the glands
of this region will be referred to as the gastric glands.
The average length of the peptic region along the greater
curvature in three animals was 28.4 cm. or 58.9% of the
total greater curvature length (Figure 1).

(The division of the epithelial surface into mam—
millated areas is not as well marked in the peptic region
as in the pyloric region (Figures 9 and 10). Simple,
straight, branched tubular glands extend upward from the
muscularis mucosae halfway to the surface where they
empty into the gastric pits or fovealae. Usually two
glands empty into a single foveala. The gastric glands
are more closely packed than those in the cardiac and
pyloric regions. A constricted neck, straight body, and
terminal coiled fundus are usually discernible.

Intermediate £232

Rather than an abrupt change from one region to
the next, towards the pyloric region the peptic glands are
gradually replaced by pyloric glands through an inter-
mediate transitional area of varying width. The intermediate
zone was first described in a variety of ruminants by
Billenkamp (1929) and has since been noted in the goat
(Hill, 1951) and sheep abomasum (Sommerville, 1956). An.
intermediate zone was observed in two.of the stomachs used
in this study. The area is characterized by gastric glands
in Juztaposition.to mucous glands and glands composed of
parietal, chief, and mucous cells (Figure 26). The level
at which the intermediate zone occurred along the greater
curvature is indicated by the vertical line in figure 1,
but it probably is located at slightly different levels
around the abomasum (Berger, 1934; Billemkamp,,l929).

gyloric Gland Region
Pyloric glands predominate at the distal end of the

intermediate zone and occupy the last 30-40% along the
greater curvature (Figure 1).. The permanent mucosal

folds give way to rugae in the pyloric region. Mammil-
lated areas are well marked in the pyloric region

by deep furrows whidh approach the muscularis mucosae
(Figure 10). The short, coiled, glands occupy the lower
quarter of the mucosa. The glands proper empty into long,
narrow, straight ducts which occupy the middle one-half
of the mucosa and empty, in turn, into short wide fovealae

14

15
on the surface and into the furrows (Figure 20). The
excretory ducts often branch once before receiving the
glands proper. Both the terms 9glandular duct? and
ffoveala' have been used by various authors to-describe
these long, straight tubules of the pyloric region. The
former term is presently employed for two reasons: ‘
(1). it is more descriptive since these tubules have a
narrower lumen than that of the glands proper and (2). these.
structures eventually open into wide-mouthed pits at the
surface which are more aptly named 'fovealae'.

All of the epithelial cells of the pyloric region are
shown to contain mucigen when stained with Southgate's
mucicarmine. The staining is most intense in the cells of
the coiled glands. The surface cells are.morphologically
similar to those seen in other parts of the stomach.

The glandular cells are similar to the mucous neck cells
of the peptic glands. Mitoses are seen deep in the glands
as well as anong_the fovealar cells. No parietal cells

are found distal to the intermediate zone.

Junction,gg Pylorus and Quodenum
Goblet cells suddenly appear among the surface cells

at the Junction. A striated border becomes apparent in

the other cells. The surface shortly takes on the
configuration of duodenal villi. {A short distance proximal
(1.6 mm. in one and 2.8 mm. in another) to these surface
changes the muscularis mucosae loses its organization
allowing for the inclusion of glands in the submucosal

layer. These quickly take on the appearance typical of

16
the submucosal glands of the duodenum. A longitudinal
section through this Junction is seen in Figure 15.

Mucosal Epithelium

Epithelial cells line the inner surface of the

abomasum, line the gastric pits, and form the glands.

Surface Mucous ggl;g

Surface mucous cells line the gastric pits as well as
the entire surface of the abomasum. The length and con-
centration of the gastric pits or fovealae varies in
different regions.. They extend to two-thirds of the
mucosal thickness in the cardiac region, half of the
thickness in the peptic region and gradually lengthen.
in the transitional zone to form the long duct-like
fovealae of the pyloric region (Figures 24 and 25).

The fovealae are more concentrated in the pyloric region
than in the peptic region. ‘
h The surface mucous cells of the bovine abomasum
resemble those seen in other animals. They are tallest
where they line the surface and gradually shorten along
the fovealae towards the glandular neck. With fixation

in.Bouin's fluid, the apical cytoplasm appears foamy
and clear (Figure 19), but fixation in Zenker-formalin
and subsequent staining with Southgate's mucicarmine
demonstrates mucigen droplets in the apical half of the
cells (Figure 21).

Mitotic figures are frequently and almost exclusively

17

seen in the fovealar cells (Figure 23). This observation.
along with other supporting evidence (Kapp,.l967) has
led most investigators to regard these cells as stem
cells from which the other epithelial constituents arise.
Recent autoradiographic studies (Hunt, 1962) have vorified
this. i

The surface mucous cells of the stomach, in contradis-
tinction to goblet cells, constantly secrete a protective“
mucous layer for the lining of the abomasum. When.this
function ceases at death,,post-mortem degeneration.rapidly
ensues and these cells are soon sloughed. The use of
slaughterhouse animals in this study necessitated a 20-25
minute delay between the time of death and fixation of
tissue. The absense of surface mucous cells in many
locatiOns and the accompanying presence of cells in the
lumen of the stomach were indicative of post-mortem

changes.

Mucogs Egg; 931;;

Mucous neck cells are present exclusively in the
upper end of the gastric glands in the bovine abomasum.
That this is typical of the ruminant is indicated by‘
Rondo 23 31‘ (1966) who reported that mucous neck cells
were limited to the upper third of the gastric glands
in the abomasum of cattle, goats, and sheep. In other
animals, including the cat (Bowie, 1940) and pig (Kendo,
23,21; 1966) these cells are scattered throughout the

gastric glands..

18

The mucous neck cells line the lumen of the glands
in the neck regioanust as the chief.ce11s line.the lumen
in the body and fundus of the glands. Parietal cells are
interspersed among the neck cells (Figures 21 and 22).
The mucous neck cells resemble the glandular cells of the
cardiac and pyloric region both in morphology and secre-
tion products (Copenhaver, 1964). The cells are more or
less cuboidal with basally-placed nuclei. Mucigen granules
fill the upper half or more of the cytoplasm and often
appear to flatten or indent the nucleus (Figure 22).

Parietal Q2115

Parietal cells are seen in all parts of the gastric
glands and even among;the fovealar cells. They usually
occupy a peripheral position, apparently wedged between
the chief or neck cells with only a small portion of the
cell surface exposed to the lumen (Figure 22).

The maJority of the parietal cells of the bovine
abomasum are morphologically similar to those described
in other animals. They possess round, vesicular nuclei
and finely granular cytoplasm. Binucleated cells are
common. In many sections atypical parietal cells are
seen. These cells possess pyknotic nuclei, intensely
acidophilic cytoplasm, and are generally triangular in
shape. Similar cells were described by Sommerville (1956)
in the sheep abomasum.

Parietal cells were counted at intervals (Figure 1)

along the greater curvature in three abomasums. The results

19
are shown in Figure 5. The mucosa was divided into
upper, middle and lower thirds and the cells were counted
in each. The numbers alongside the bars indicate what
percentage of the total cell count was located in that
third. An average of 61.4% of the total cell count was
located in the lower third (Figure 19), 37.9% in the middle
third (Figure 18), with only 0.7% in the upper third
of the mucosa (Figure 17). If only the length of the
glands is considered, parietal cells are seen to be most
numerous in the neck and upper portion of the body region.
The number of parietal cells gradually increases from the
cardiac region, reaches a peak approximately two-thirds
along the length of the peptic stomach, and thereafter
decreases to the pyloric zone. Where the counts are
highest the spread of cells is also greatest so that
relatively more cells are found in the middle and upper.
thirds at these levels. The decrease in the number
of cells towards the pyloric region is accompanied by
a decrease in the length of the glands with s complemenr
tary increase in the length of the fovealae (Figures 24
and 25). Uhen the intermediate zone is reached (Figure.
26),,mucous glands begin to appear among the gastric
glands..

Studies of parietal cell distribution in ruminants
and other mammals were available for comparison. Kondo'
23 31;, (1966) reported that parietal cells were most
numerous in.the mid-body region of the abomasum in goats,

sheep, and cattle.. In cattle, however, he observed that

20

counts remained at a high level to the pyloric region.
other investigators doing similar studies in the sheep
(Sommerville, 1956) and goat (Hill, 1951) reported that
parietal cells were most numerous at the beginning of the
peptic region and decreased towards the pyloric region.
Results similar to those obtained in the present study
have been presented for the cat (Read and Johnstone, 1961)

and human (Berger, 1934).

9.122.229.2232

The chief or peptic cells line the lumen in the
body and fundus of the gastric glands. They have a more“
restricted distribution than the parietal cells, since
they are rarely seen in the cardiac or pyloric regions.

The chief cells of the gastric glands in the bovine
abomasum appear to be morphologically similar to those
described in other animals. The basal nucleus lies in
the basophilic cytoplasm. The apical cytoplasm appeared
foamy and empty in sections fixed in Bouin's fluid, but
in others zymogen granules were fixed in 10% formalin
and stained with orange G (Mallory's triple stain).

The results of counting chief cells along the greater
curvature in three abomasums are shown in Figure 6. The
mucosa was divided into upper, middle and lower thirds._
No chief cells are observed in the upper third. The
greatest concentration of these cells is in the lower
third (94.2% of all cells counted) and in two sections,
all of the cells are in the lower third (Figure 6).

21.

If only gland length is considered, chief cells are
seen to be most numerous in the lower half of the body
and in the fundus of the glands (Figure 19). Kondo
gt 3;; (1966) reported on the location of the chief
cells in the abomasum of the goat, sheep, and cattle:
60% were located in the basal one-third of the glands,,
30% in the middle third,,and 0% in the upper third of the
glands. From the cardiac region chief cells begin to
accumulate shortly after the appearance of the parietal
cells and disappear somewhat before the parietal cells
in the area of transition to the pyloric region. Chief
cells reach a high level a short distance from the cardiac
region and continue to be numerous throughout the peptic
region to the intermediate zone where they disappear
fairly rapidly.

A similar distribution for the ruminant abomasum
in general is reported in the literature. Studies of
the abomasum in the goat (Hill, 1951), in sheep (Sommer-
ville, 1956) and in cattle (Kondo, 1966) showed chief cells
to be numerous Just distal to the cardiac region and to
continue at a constant level or decrease slightly until

the pyloric region where they abruptly disappear.

Argentaffin Cells
Argentaffin cells were demonstrated with the Bodian

Protargol method (Dawson and Barnett, 1944). In the
bovine abomasum these cells are morphologically similar

to those described in various animals. Impregnation

22

with silver produces dense, dark staining cytoplasmic
granules and a negative image of the nucleus. The cells
are round or teardrop-shaped with the granules concen~
trated at the base away from the glandular lumen.
The argentaffin cells are positioned along the basement
membrane between adjacent mucous or chief cells (Figure 29).

Argentaffin cells were counted in the upper and lower
halves of the mucosa at intervals along the greater
curvature in specimens from two animals.. The cells could
not be distinguished well enough for cell counts in the
third stomach fixed in 10% formalin. Bouin's fluid gave
good results in fixation of the cytoplasmic granules and
their subsequent impregnation by the Bodian Protargol
method. As shown in Figure 7 argentaffin.cells are
abundant throughout the abomasum. Likewiseg sections
through the omaso-abomasal Junction and the pylorus con-
tain numerous argentaffin cells. Most of the cells are found
in the lower half of the mucosa. 0f the total cells counted*
in stomach A, 89.2%-were located in the lower half of the
mucosa; the corresponding figure in stomach B is 81.5%.
In the pyloric region the cells are more widely spread so
that more argentaffin cells are located in the upper half of
the mucosa (Figures 27 and 28). 0f the total cells counted
in the pyloric mucosa in stomach A, 30.2% were in the
upper half compared to 10.0% in the peptic region; the
corresponding figures in stomach B are 15.6% compared to
11.1%. Comparative interpretation of counts in the peptic

and pyloric regions should take into account the differences

23
in mucosal thickness between the two regions. Argentaffin
cells are evenly distributed between the peptic and
pyloric regions. 0f the total cells counted in stomach
.A,,48.7% were located in.the peptic region and 51.3% in
the pyloric region. Comparable figures for stomach B
were 51.6%and 48.4%.

Much of the literature, however, indicates that the
argentaffin cell population in the pyloric mucosa is
quite low in many species. Dawson.(l945) reported that;
argentaffin cells were relatively sparse in the pyloric
mucosa of the rabbit, guinea pig, mouse, and hamster.
A.report by Tehever (1930) that argentaffin cells were
absent from the pyloric region in.sheep was later confirmed
by Sommerville (1956). Bharples (1945), however, observed
that argentaffin cells were only slightly less abundant
in the pyloric region of the human stomach,,and Hill
(1951) noted that these cells were quite numerous in the.
pyloric region of the goat abomasum. It is possible that
the negative results obtained by Tehever and later by
Bommerville were attributable to their failure to employ
the Bodian.method.

globule Leggocytes
Globule leukocytes are present among the epithelial

cells in all material examined in this study. The
acidophilic cytoplasmic granules are readily distinguished
at low power in sections stained with Mallory's triple

stain.

 

all" 4I||Illl"li

 

24

The globule leukocytes of the bovine abomasum appear
to be similar in morphology and position to those described
in the sheep abomasum by Keasbey (1923),,and in various
monogastric animals by Weill (1919). The cells are
typically located along the basement membrane between two
of the regular constituents of the epithelium (Figure 30).
The colorless cytoplasm is characterized by the presence
of acidophilic bodies of varying size and number. The
nucleus is usually flattenedbut may be oval, or even
round.. The arrangement of the chromatin is similar to
that seen in the lymphocyte nucleus. The nucleus is
eccentric or, more often, peripheral.

The distribution of globule leudocytes along the
greater curvature in three abomasums is shown in Figure
8. The mucosa was divided into upper and lower halves for
the counts. Although present in each stomach, the number
of cells in each is quite variable. Globule leukocytes
are present in the lower layers of the stratified squamous
epithelium of the omasum near the junction and also are
numerous in the cardiac region. Figure 8 shows that the
cell counts reached two peaks, one in the peptic and one
in the pyloric region, in each of the three abomasums.
‘Near the pylorus globule leukocytes appear less frequently
and only a small population appeared in the duodenum. In
most animals these cells are more numerous in the small
intestine” but these observations together with those of
Keasby (1923) on sheep indicate that, in the ruminant, the

25.
abomasum is the primary location for these cells.

Globule leukocytes occur predominately in the upper
half of the mucosa (Figure 8), especially among the fovealar
cells. With an increase in the total number of cells
at a given level, the spread likewise increases so that
proportionately more are found in the basal half. 0f
the total number of globule leukocytes counted, 81.1% were
in the upper half of the mucosa..

Contrary to these findings, Keasbey (1923) reported
a higher concentration in the upper half of the mucous
membrane in the sheep abomasum. The highest numbers of
cells were observed Just proximal to the intermediate zone
in the sheep. The distribution was, however, subject to
considerable individual and local variation, not unlike that
seen in the present study.

Recent evidence indicates that the occurance and
distribution of globule leukocytes are influenced by
exogenous factors. Sommerville (1956) was able to find
the cell only in the abomasum of sheep with a prolonged
nematode infestation. Likewise,.Whur (1966) was able to
correlate the occurance and concentration of globule
leukocytes with gastrointestinal infections in sheep and
rats. It is not yet clear whether the globule leukocytes
should be considered a normal constituent of the gastro-

intestinal mucosa.

mm

The subepithelial connective tissue consists of a
fine reticulum which is more or less infiltrated with
various connective tissue cells. In addition to reticular
fibers (Figure 33), fine elastic and collageonous elements
contribute. The lamina propria of the ruminant abomasum
is very cellular and in this regard resembles the inter-
glandular connective tissue of the small intestine as
described in other animals (Brugnone, 1811, Keasbey, 1923).
Lymphocytes, fibrocytes, and primitive reticular cells V
or fibroblasts are abundant throughout the layer.- Plasma
cells are most numerous in the interfovealar connective
tissue (Figure 30). Eosinophils occur in the pyloric
region from the muscularis mucosae to the surface mucous
cells; in the peptic region they are found almost ex-
clusively Just above the muscularis mucosae. Scattered
monocytes and neutrophils are also present.

Solitary lymph nodules are seen in all regions of
the abomasum. Often they are quite large with germinal
centers and obvious efferent channels. A few had pene-
trated the muscularis mucosae to extend into the sub-
mucosa.

Vsscular patterns in.the mucosa were studied in
thick sections. Large arteries in the submucosal layer
send smaller branches through the muscularis mucosae.
These extend parallel to and Just above the muscle giving
off perpendicular branches which quickly break up to

26

27
form a periglandular capillary network. In the inter-
fovealar connective tissue these coalesce to form venules
which return blood to the submucosal veins. These inter-
fovealar venules are quite long between the long ducts
of the pyloric glands. Large lymph channels are apparent
near the muscularis mucosae.

Ganglion cells, occurring either singly or in small
groups, are regular feature of the lamina propria just
above the muscularis mucosae. These multipolar cells
average 20-25 micra in diameter and resemble the ganglion
cells of the submucosal and myenteric plexuses (Figures
31 and 32). Inumost cases encapsulation was incomplete.
The Bodian stain revealed nerve fibers adjacent to these
cells but it was not possible to follow these. Although
reports of a mucosal plexus are generally absent from the
literature, Habel (1956) described extensions of the sub-
mucosal plexus into the lamina propria in the sheep
abomasum.

Counts of ganglion cells with regard to frequency
of ganglion cell groups and number of cells per group
indicate some regional variation. The number of cells
per group was lowest in the proximal peptic area
(average of 1.6 cells per ganglion) and progressively
increased distally to reach an average of 3.0 cells per
ganglion in the distal pyloric region. The frequency of
ganglia was highest in the distal peptic and proximal
pyloric areas (average of 11.9 ganglia per cm. ) and

lowest at either end (average of 6.4 ganglia per cm. in

28
the proximal peptic and 5.7 ganglia per cm. in the distal
pyloric region). The number of cells per ganglia is lower
in the mucosa than in either the submucosal or myenteric
p1exuses.but the number of ganglia per centimeter is
much greater. Of the total number of ganglion cells
present in the wall of the bovine abomasum, the greatest

number of cells are located above the muscularis mucosae.
Muscularis Mucosae

The musculature of the mucous membrane consists of
a narrow band of smooth muscle fibers with circular, long-
itudinal, and oblique orientations enmeshed in a fibro-
elastic network. In the peptic region circularly arranged
fibers predominate; the increase in thickness of this
layer seen in the pyloric region is due in part to the
addition of longitudinal and oblique fibers. Distinct
layers are not observed.

The muscularis mucosae sends strands of smooth muscle
fibers into the interglandular connective tissue which
often can be followed to the level of the necks of the
glands (Figure 32). These extentions of the muscularis
mucosae are most prominent in the pyloric mucosa. Just
proximal to the junction with the duodenum the muscularis
mucosae is disassembled and mucous glands pass into the
submucous layer.

Changes in the thickness of this layer along the

greater curvature in three abomasums are shown in Figure 3.

29
Local variations in thickness associated with mucosal
folding were avoided in an attempt to obtain a true
average measurement for a particular area.. Nevertheless,
such local disruption may have contributed to produce
the conflicting results shown in Figure 3. A slight
increase in thickness is indicated along the greater
curvature in the peptic region.. The muscularis mucosae
of the pyloric region is substantially thicker. This
was described in the ruminant abomasum very early by
Ellenberger (1827, 1884),.as reported by Oppel (1896).
The increase in thickness is not only due to an increase in
the number of muscle cells but to an increase in the amount
of interglandular connective tissue as well. This observa-
tion correlates well with the report by Walder (1956) that
the muscularis mucosae of the pyloric region in the human
stomach is capable of greater contraction.than that of the

more proximal regions.

Submucosa

The submucous layer is composed of loosely-arranged
collagenous tissue, some elastic fibers, and a great
deal of adipose tissue. Adipose tissue is often the pre-
dominant component especially where the submucosa forms
the rugal folds (Figure 13). At the lower end of the sub-
mucosa the collageonous fibers condense to blend with the
fibers which surround the bundles of smooth muscle of the
muscularis externa. Here many elastic fibers are seen

among the collagen.

30

Compared to the lamina propria, the submucosa has
much.fewer connective tissue cells. Fibrocytes are the
predominant type. Extensions of the lymphatic nodules of
the lamina prepria are frequently seen in the connective
tissue just beneath the muscularis mucosae.. Occasionally
lymphatic foci are seen in the submucosa.

Multipolar ganglion cells and nonmyelinsted nerve
fibers are readily seen in this layer (Figure 34 and 35).
The cell bodies invariably lie directly beneath the
muscularis mucosaevflflle small bundles of fibers are seen,
throughout the layer.. The ganglia occur much less fre-
quently than those above the muscularis mucosae but each‘
submucosal ganglion generally contains more ganglion cells
(5-10 cells per ganglion). The cells appear morphologically
similar in all respects to those of the mucosa. They
are usually more completely surrounded by capsule cells.

Large arteries, veins, and lymphatic are located
in the submucosa. Smaller branches of these vessels

presumably serve the mucosa and muscularis externa.

Muscularis Externa
The muscular coat of the abomasum appears to possess
the three layers usually described in the mammilian stomach;
inner oblique, middle circular, and outer longitudinal.
The circular layer is the thickest throughout the abomasum,
while the longitudinal layer is thin in many areas.
An oblique layer is only distinguishable in the pyloric

region. The circular layer is thickest where it forms a

31
sphincter at the pylorus (Figure 15).

The muscularis externa was measured at intervals
along the greater curvature in three stomachs (Figure 4).
The coat is somewhat thinner just distal to the cardiac
region but no consistent changes are recorded through the
peptic region. From the intermediate zone the muscularis
externa thickens towards the pylorus. This increase is
due to the appearance of an oblique layer and a progressive
increase in the number of circularly-arranged fibers“

The outer longitudinal layer is also somewhat thicker at
the pylorus. Representive samples are shown in Figures
ll, l2, l3, l4, and 15.

Between the two outer layers of muscle the myenteric
plexus is seen. Large bundles of non-myelinated nerve.
fibers and varying numbers of multipolar cells are evident
(Figure 36).. Classification of ganglion cells according
to the Dogiel system was impossible with the methods here
employed. Large ganglion cells (75 mm. in diameter) described
by Habel (1956) and Kolossow (1933) in the abomasum of
sheep and goats were not observed in the bovine abomasum.
An extensive capillary system is associated with the
nervous elements. Bundles of nerve fibers and blood
vessels course in the inter muscular connective tissue.
Reticular fibers surround the individual smooth muscle
cells (Figure 37).

Sercsa

The abomasum is completely covered by a serosa con-
sisting of dense fibroelastic connective tissue with a
mesothelial covering. Adipose tissue is present in vary-
ing amounts (Figure 12). This layer is much less cellular
than either the lamina propria or submucosa. Blood vessels
and nerve fibers are commonly seen coursing through the
layer.. In one section ganglion cells were observed just

beneath the mesothelium.

32

SUMMARY

A study of the histology of the bovine abomasum as
seen in eight animals is reported. The topic is introduced
by a brief description of the general macroscopic topogra-
phy of the abomasum.

0n the basis of their histology, four regions are
distinguished. A narrow zone of mucous glands at the omaso-
abomasal junction is demonstrated and the width of this
region is noted in three animals. The peptic region is
defined and the morphology of the gastric glands and
fovealae is described. An intermediate zone between the
peptic and pyloric regions was seen in two abomasums. The
transitional characteristics of the glands in this region
are reported. The micro-relief elements and the glands in
the pyloric region are described. The cells of this region
are compared to cells found in the other regions. Changes
taking place at the abomaso-duodenal junction are reported.

The cells of the abomasal epithelium are described
according to their morphology and location. Surface
mucous cells line the inner surface of the abomasum and
the fovealae. The presence and signifigance of mitotic
figures in these cells is explained. Difficulty in the
postmortem preservation of the surface cells is also
noted. The morphology of the mucous neck cells of the
gastric glands is described and their limited distribution
in the bovine abomsum is noted. The parietal and chief

cells of the gastric glands are described according to
33

34

morphology and location. Demonstration of argentaffin

cells with the Bodian Protargol method is discussed. A
constant feature of the mucosa, the globule leukocyte,

is described.

Quantitative observations of certain aspects of the
histology along the greater curvature of the abomasum in
three animals are presented. Globule leukocytes, parietal,
chief, and argentaffin cells were counted. Globule leuko-
cytes were present in all material but the number of the
cells was subject to considerable local.and individual.
variation.. They are located predominately in the upper
half of the mucosa.. Parietal.cells are nearly confined to
the lower two-thirds of the mucosa and are most numerous
in the upper half of the glands themselves. The number of
parietal cells gradually increases from the cardiac region,q
reaches a peak approximately two-thirds along the length
of the peptic region and thereafter decreases to the
pyloric zone. Parietal cells are found in the cardiac-
region but not in the pyloric region. Chief cells are
nearly limited to the lower third of the mucosa. Chief
cells are most numerous a short distance from the cardiac
region and maintain this level until a short distance
from the pyloric region where they decrease fairly rapidly.
They are not found in the cardiac glands. About 85% of
the total number of argentaffin cells counted are found in
the lower half of the mucosa. Argentaffin cells are evenly

distributed between the peptic and pyloric regions.

35

The thicknesses of the mucosa, muscularis mucosae,
and muscularis externa were measured along the greater
curvature in three animals. Little change is seen in the
thickness of the peptic mucosa but the pyloric mucosa
shows a progressive and sharp increase towards the pylorus.
The muscularis mucosae shows local variations in thickness
and an overall increase in thickness towards the pylorus.
The muscularis externa is thin and shows little change in
the peptic region but also increases towards the pylorus
where it is markedly thickened.

The composition of the connective tissue of the lamina
propria is described.. Its high cellularity is noted and
the various cell types present are enumerated.. Lymph
nodules are abundant. The vascular pattern of the mucosa
is presented. Ganglion cells, similar to those seen in
the submucosal and myenteric plexuses,,are a regular fea-
ture above the muscularis mucosae.in the bovine abomasum.
Counts of ganglion cells in this layer with regard to
frequency of ganglia and number of cells per ganglia are
reported.

The arrangement of muscle fibers in the muscularis
mucosae is described. The presence of strands of smooth
muscle cells between the glands is also noted.

The composition of the connective tissue.of the
submucosa is compared to that of the lamina propria.

The presence of a great deal of adipose tissue is reported.
The submucosal plexus is briefly described with regard to
location and morphology of the ganglion cells. The pre-

36
sence of large arteries, veins, and lymphatics in this
layer.is noted.

The composition and arrangement of the muscularis
externa in the various regions of the abomasum are-described..
The nerve plexus of this layer is briefly described.
The intermuscular connective tissue is demonstrated.

A brief description of the composition of the ser-

osal covering of the abomasum concludes the report.v

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Domestic Animals. W. B. Saunders Company, Philadelphia
and London.

Sokolowa, H. L. 1931. Zur Lehre von der Cytoarchitektonik
des peripherischen autonomen Nervensystems, II. Die
Architektur der intramuralen Ganglien des Verdauung-
strakts des Rindes. Z. mikr.-anat. Forsch., 23:552-
570.

Sommerville, R. I. 1956. The histology of the ovine abomasum,
and the relation of the globule leukocyte to nematode
infestations. Aust. vet. J., 32:237-240.

Tamate, H., McGilliard, A. D., Jacobson, N. L. and Getty, R.
1963. The effects of various diets on the histological
development of the stomach of the calf. Tohoku J.
381.10. R68., 143171-193.

Tehver, J." 1930. fiber die enterochromaffine Zellen der
Haussaugetiere. Z. mikr. anat. Forsch., 21:462-496.

Tehver, J. 1939. The microrelief elements of the stomach
and intestine in domestic animals. Acta et Comment.
Univ. Tartu. Dorpat. Biol. Abst. 16:815.

Walder, D. N. 1953. The muscularis mucosae of the human
stomach. J. Physiol. 120:365—372.

Weill, P. 1919. Uber die leukozytaren Elemente der
Darscgleimhaut der Saugetiere. Arch. mikr. Anat.,
93:1- 00

Whur, P. 1966. Relationship of the globule leukocyte to
gastrointestinal nematodes in the sheep, and
Nippostrongylus brasiliensis and Hymenolepsis nana
infections in rats. J. comp. Path., 76:57-65.

41

FIGURES

42

Figure l. Abomasi showing levels at which samples were taken.

01118811111

    
   
   

pyloric ] duodenum
9 10

Animal #A - length along greater curvature - 61 cm.

011218.811!!!

 
    

pyloric ‘| O duodenum
8 9

Vpnn-p-

Animal #B - length along greater curvature - 42 cm.

omasum

   

pyloric
8

duodenum

  

.
I
------

45 7

Animal #C - length along greater curvature - 47 cm.

43.

Figure 2. Variations in thickness of the mucosa.

 

 

 

 

 

 

 

 

 

2000 -
' A10
1600 - /
.. 118’,
1200 - A5 / A9
microns - A2 Ah3fifi6 A7
. ‘__ A
800.. A3 A4
400'-
20 40 60 80 100
2000 ‘
1600 r
‘ B9
1200 "'
microns ‘ Bl 54,;?5 A’s/l’1§;‘fl‘—‘
.. 32 33 B6
400 -
20 40 60 80 100
C9
2000 “f
1600 -
1200 - 02 C} 08
microns - u - fi__ 06
800 - f 04 c7
_ Cl ’
400 q
.4
4..— T a
20 40 60 80 100

per cent of length

O
7“. - WHO...

0
.

O
“or

. L. ‘ ‘ ‘0.
‘Q.
1 '— ‘1.

0'. T.';-f.‘-fl_‘uw

...-
u on”

‘I.
C
.-

. ._- ... .. _ , .', . e ... '-‘ s..-u-._. '1.“ hf”... 4a-...‘4 A‘—' ...D' .0 ' K _. ".19.; 3. .... X.

1\

-‘ .
§~w...v .~.'

u
IJ‘IQA

a‘ I

44

Figure 3. Variations in thickness of the muscularis mucosae.

v

140]

 

 

 

120 s
microns 80 d _ A9 A10
- ~
40 -A2 A3 A4 A5 A6 7 A8
20 40 60 80 100
140
139
120 B8

microns 8°

_ B6 37
40—13113sz ME/

A‘—

‘

 

 

j.—

 

 

 

 

20 4O 6O 80 100
140 fi'
d
microns 80 _
" 05 c6
40 q 01 02 C} C4
4 ——‘* 07
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20 40 60 80 100

per cent of length

v

Q
.
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.
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.
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45

Figure 4. Variations in thickness of the muscularis externa.

microns

microns

microns

5000
4000
3000
2000

1000

5000
4000

3000

2000

i000

5000

4000

3000
2000

1000

 

 

 

 

 

 

 

 

1
"i
- 'AlO
- A2 ‘3 16”,
- A9
-‘ afl*-§~..--~‘———. A6 Ilfgr’f
-“\, A

20 40 60 80 100
1
d
d B
: BS B7 9

Bl -— B8

'3 0%} BA B6
A B2

20 40 60 80 100
‘ C9
2 03 05 c7

02

" /——--/\c?k 78
“L c1 64

20 40 60 80 100

per cent of length

h
I.
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.‘~
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g
I I
.
‘ -D
Q .4"
o ‘ fl
5. a
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- O
Q
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1
......J

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bfifi“.

45

Figure 5. Variations in the number of parietal cells in the
lower, middle, and upper one-third of the mucosa.

number

of

-, ..2 1»-
parietal

cells

number
of
parietal
cells

11111.“. I) C r

aristal
cells

01:3

800
1

600 a

J

4004

200 ‘

 

600 1

l

600'“

400'-

zoo-—

 

800 -«

600 -

400

200"

 

*per

 

 

 

 

A2
‘ ,
30 3*
63.
10 20
B4
B3 ‘
R : 39.8
Bl 46.7 B:
S 43.4 . 33.9
~ 60.0
49.5 65.7
56.3
10 20 :0 4o 50 60
c
01

I.
U!
0')
O
N

61.8

 

10

cent of total

 

per cent of length

cells at that level

r; ‘.J. vl‘c'. 1 ‘1‘1. 07!.1. 8‘ t

‘I

\D.’ C u

5

'f!‘

47

Figure 6. Variations in the number of chief cells in the
lower, middle, and upper one-third of the mucosa.

 

 

 

 

 

800 0
- .A2
number 600 d ‘1 4.1”
of
chief d
cells 400
" 5.6
200 ‘
...-1
10 20;
800 ‘
number 500 "31
of -
chief 7'6
cells ‘00 "'
- 92.4 94 7
200 ‘
10
800 ‘
‘ ’c4
_ 01
nmnberGOO 9.4 03 1.0
{if r d 7‘ 6'5 C6
c e
cells 400 1 5 9.0 1.8
q 900 9 .5
200 - 3 98.2 c7
‘ 100.0

 

 

10 20 30 40 50 60

per cent of length

*per cent of total cells at that level

I “‘.‘ 0...u.n|\v. ’.z§’n§a‘ .... ...:

a
..
.A

I

c

U

'

s

N

V
s
I
’
‘
o
ashlar; ; \I
..
~
Q
'
w

"s‘

.5.

‘Oll‘:

...{0

.DA.‘ .g N“

s urVI, \_- -

’l

o .L ' n- 0 I0: IL! ,1 Q ... 4..

48

Figure 7. Variations in the number of argentaffin cells in
the lower and upper one-half of the mucosa.

 

 

 

1200 3
1000 45
“ 44 12.8
800 ‘ A2
number ‘ 10 1* 9.4
of ‘
cells 500 4
- 87.2
400 -
_ 89.9 90.6
200 ~
d
20 40 60 80 100
1200
1000
800
number I
of 11.2
cells 600.

400
88.8

200

 

 

 

20 40 60 80 100

per cent of length

*per cent of total cells at that level

 

I‘ll!» nll. 0"“...3‘1‘1.

.I‘v

an ~r s. 1"

ans

'0'

u".

49

Figure 8. Variations in the number of globule leukocytes in the
lower and upper one-half of the mucosa.

 

 

 

 

 

 

 

800 P
- A9
600 9 A4 :
number 3 . A8 ‘77 9
0f #00 '1 e
globule _ :55.9 A6 ‘ ~
leukocytes A2 ~
200 r [ .
I 24.0
20
1200 ‘
1000 ‘
800 ‘
number -
of
globule 50° -
leukocytes -
400 ‘
200 "' B}
- Bl78.6 .81.? 134 81.0
“ I 21,4 .18.} r 19.0
20 40 60 80 100
number 400 :
O O ...4 .
leukocytes 200 Cl . 88.3CA C7 ‘<88.l
‘ | 81.2 Q89.1 93.6 Q 09 90.6
1 .8 ll. 10. 6 4 11.9 i 9.4
20 40 60 80 100

per cent of length
*per cent of total cells at that level

2|"... 1..

C!

'.'I..\" .3

\ql-

O-‘av‘

‘.o

‘C-.. n

SO

 

Figure.9. Surface view of the lining of the abomasum
in the peptic region. a, mamillated area; b, openings
of gastric pits. x20

51

 

Figure 10. Surface view of the lining of the abomasum
in the pyloric region. a, mamillated areas; b, openings
of gastric pits; c, hairs embedded in mucosa. x16

.1:
C
_“
{Q

L

J’
-1";

 

Figure 11. Wall of the peptic region at level A2.
a, mucosa; b, muscularis mucosae; c, adipose tissue
of submucosa; d, muscularis externa; e, serosa.
Hematoxylin and eosin. x30

 

Figure 12. Wall of the intermediate zone at level A7.
a, mucosa; b, muscularis mucosae; c, submucosa; d,
muscularis externa; e, serosa. Hematoxylin and eosin.
x50

Figure 130
mucosa; b,
submucosa;
and eosin.

54

 

Wall of the pyloric region at level A9. a,
muscularis mucosae; c, adipose tissue of

d, muscularis externa; e, serosa. Hematoxylin
x30

Figure 14.
a, mucosa;
submucosa;
and eosin.

55

3&4"

'\' - nfi-‘y " V“ '

‘ “\Eé swift...» v

  
   

23'

 

Wall of the pyloric region at level A10.
c, adipose tissue of

b, muscularis mucosae;
d, muscularis externa;
x30

serosa. Hematoxylin

56

s“ L'

“spam-
"% _\

,3,1-L.'
Iv "a

;

\Q\'J‘// , _.‘_

 

Figure 15.. Longitudinal section of the junction of
the pylorus and the duodenum. a, pyloric sphincter
muscle; b, duodenal glands of Brunner. Arrow marks
the epithelial Junction. Hematoxylin and eosin. x10

57

 

Figure 16. Longitudinal section of the Junction of

the omasum and abomasum. a, omasal epithelium; b, car-
diac glands; 0, surface mucous cells; d, neck mucous
lymphocytes. Southgate's mucicarmine. x130

\ IV
Ll‘v

 

Figure 17. Upper third of the peptic mucosa. a, gas-
tric pits; b, surface mucous cells; 0, cellular lamina
propria. Hematoxylin and eosin. x460

 

Figure 18. Middle third of the peptic mucosa. a, necks
of glands; b, neck mucous cells; c, parietal cells.
Hematoxylin and eosin. x460

 

Figure 19. Lower third of the peptic mucosa. a, chief
cells; b, parietal cells; c, neck mucous cells.
Hematoxylin and eosin. x460

 

Figure 20. Pyloric mucosa showing mamillated arrangement.
a, surface mucous cells; b, pyloric glands; 0, long ex-
cretory ducts of fovealae; d, muscularis mucosae; e, a
hair embedded in the mucosa surrounded by lymphocytes.
Hematoxylin and eosin. x130

62

 

muscularis

d
in lamina propria.

a, surface mucous cells;

; c, parietal cells

The peptic mucosa.

b, neck mucous cells
mucosae; e, chief cells; f, large vein

Southgate's mucicarmine. x190

Figure 21.

63

r’
I

 

c
0

Figure 22. Neck region of the gastric glands. a, neck
mucous cells; b, parietal cells. Southgate's mucicarmine.
x1590 -

64

  

D :v‘ ?
g I”: ". "

 
    
 

“ .
I .
v v .

  
 
 

 
  
 
 
  

O

 
  

 

4 1 

Figure 23. Two mitotic figures among the cells which
line the fovealae. Mallory 3 triple stain. x840

65

 

The mus-

cularis mucosae is seen at the bottom of the photograph.

Figure 24. The peptic mucosa at level A4 showing a rel-
Hematoxylin and eosin. x165

ative high number of parietal and chief cells.

66

 

fovealae and relatively fewer parietal and chief cells.

The muscularis mucosae is seen at the bottom of the

Figure 25. The peptic mucosa at level A7 showing long
photograph. Hemetoxylin and eosin. x165

 

Figure 26. The glands of the intermediate zone. a,
gastric glands adjacent to b, pyloric (mucous) glands;
c, muscularis mucosae. Hematoxylin and eosin. x240

68

 

I
Figure 27. Distribution of argentaffin cells showing
a high concentration in the lower half of the peptic
mucosa. The muscularis mucosae is seen at the bottom of
the photograph. Bodian Protargol method. 1110

69

. ,
Q. J- I.
- .51.... vocals? ....

. Qua.
. . .14.. .\ .1...»
. 5&3; ...3w.

,5. a. W~0144o0 ..Hu..r.r—v.1§hH/.hv.
.Q A O .. ...(Ic\s \anloor ‘1
t,» ......Fuimmnfi an. . ... .. .. fixwmmwm.
.. N ~ . . s.‘ D 1
..1 I .‘AHIELJVn\.<\1..1..H./.u ..u..¢.1.t.-....u.....014. .4.
......) wt .\.tlw.2m\~...11.\¢l_lo. ..\
. I a \1.\ .12.J.\v‘“.,.}"ruwd.
4.5 if .n rxn‘v‘ ,’ ‘5'. fl p‘IJfln
..... (1 1 v; \:.ol\l’\$

- ,
l '-

pm».

1.~I‘+.‘ .

Ij3sAHM~¥n “jig-11. .

‘-.§

..1 ... (Aims? 71mm.
.. . ..f v If“...
3:33.... $.99...

. .. 213.03“. «“33... .

. 4

.....Ar. r..
Ex.‘v .

.Wcirul.

 

Figure 28. A more even distribution of argentaffin cells
as seen in the pyloric mucosa. Bodian Protargol method.

1110

 

Figure 29. High power view of argentaffin cells.
Bodian Protargol method. x2780

'71

 

. \

Figure 30. Globule leukocytes among the fovealar cells.
a, globule leukocytes; b, surface mucous cells; c, plasma
cells. Mallory's triple stain. x1670

72

 

Figure 31. .A protion of the mucosal plexus. a, mucosal
ganglion cells; b, parietal cells; c, chief cells; d,

muscularis mucosae; e, two fibroblasts. Hematoxylin and
eosin. x990

73

 

Figure 32. High power view of the peptic mucosa. a,
mucosal ganglion cells; b, parietal cells; c, chief
cells; d, smooth muscle cells delaminating off e, the
muscularis mucosae, and extending between the glands.
Hematoxylin and eosin. x1280

7A

 

Figure 33. Reticular network in the lamina propria.
Bodian Protargol method. 1690

 

Figure 34. A portion of the submucosal plexus of
Meissner. a, ganglion cells; b, gastric gland; c, cell-
ular lamina propria; d, cellular submucosa; e, muscula-
ris mucosae. Mallory's triple stain. x260

 

Figure 35. Silver impregnation of a portion of the
submucosal plexus. a, ganglion cells; b, nerve fibers;
c, muscularis mucosae. Bodian Protargol method..x990

77

 

A portion of the myenteric plexus of Auerbach

a, ganglion cells; b, nerve fibers; c, capillaries; d,

muscularis externa. Mallory's triple stain. x260

Figure 36.

 

Figure 37. Reticular fibers surrounding smooth muscle
cells in the muscularis externa. Two "corkscrew" nuclei
indicating contraction are marked by arrows. Bodian
Protargol method x450

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