by Injection Method of Acrylic Resin

17 Pages·2012·4.01 MB·English

Cubical Anatomy of Several Ducts and Vessels
by Injection Method of Acrylic Resin
IX. On the vascular system of the suprarenal gland
in dog and cat
By
Hakuro Okano, Yoshikuni Ohta,
Hidekazu Sawa and Issei Fujiwara
Department of Anatomy, Osaka Dental College, Osaka
(Director : Prof. Y. Taniguchi)
(with 29 figures in 4 plates)
This research was announced at 61st Annual Session of the Japanese
Association of Anatomists, 1956, Kumamoto.
Preface
Studies on the vasculature in the suprarenal gland have been
active with advance of the endocrinology in the nineteenth century,
and recently, receiving impetus from the S e 1 y e's stress theory ('50),
have come to the fore more. There naturally are much difference
of opinion about the blood circulation in the gland. Reports on the
blood supply with some cubical specimens are few ; Flint ('00) with
the W o o d's metal and celloidin in dog ; Bennet et al . ('40) with
the methyl metacrylate in cat ; and N i s h i n a ('50) with polyester in
dog, cat, cattle and rabbit.
In this paper, an attempt to observe the vasculature in the
suprarenal gland of dog and cat, chiefly by injection method of the
acrylic resin, has been made as part of comparative researches in
mammals.
Materials and Methods
For the present investigation, 21 dogs and 15 cats are used . The
method published by Tani g u c h i, Ohta and T a j i r i ('52) and its
553
554 H. Okano, Y. Ohta, H . Sawa and I. Fujiwara
supplement ('55), are employed to make corrosion specimens .
The animals are led to depletion death. Arteries to the gland
in situ are injected through a cannula inserted into the adbominal
aorta with the red-coloured resin ; veins , into the inferior vena
cava or adrenolumbar vein with the blue-coloured. Some of the glands
injected are made into serial sections stained with iron-H.
Besides, to supplement a deficiency in the resin injection , indian-
ink is injected into arteries of the gland . Observations are always
proceeded in combination with the corrosions, both serial sections
injected with resin and indian-ink, under binocular magnifier and
microscope.
Observations
A. Arterial system
Dog :
1. Plexus extracapsularis, Rete intracapsulare et Reticulum capil-
larium infracapsulare (s. subcapsulare) (Figs . 4, 5 and 6).
Small arteries approaching the gland ramify themselves over
again in surrounding adiposal tissues at the posterior surface and
fringe of the gland. They construct an arterial plexus (50-190 u)
that spreads chiefly in the frontal plane . It is named Plexus extra-
eaPsularis.
Arterial branches out of the plexus enter into the fibrous cap-
sule, where the branches make further ramifications (25-55 u) to form
an arteriolar network of a single layer. It is named Rete intracaP-
sulare. Some of branches rising from the rete send off capillaries
to the capsule only.
Moreover, arterioles out of the rete branch and anastomose rich-
ly, then form an arterial capillary network (8-20 p) , of which open-
ings are smaller than those of the rete . The reticulum is situated
directly under the capsule and covers the whole surface of Zona
glomerulosa. It is named Reticulum caPillarium infracapsulare (s. sub-
capsulare).
2. In the cortex.
Capillaries from the subcapsular network run inwards
, twining
around cell cords and anastomosing one another abundantly . Mesh-
work in Zona glomerulosa is fine and irregular lattice . but in Zona
fasciculata, elongated (corticomedullary) latticework . This meshwork
abruptly transfers to thick venous capillaries getting to the outer
Vascular System of Suprarenal Gland in Dog and Cat 555
1/3 of the fasciculata (Fig. 7).
Besides, arterial branches are found as follows : Some branches
of the extracapsular arterial plexus directly turn to the subcapsular
network, without joining the intracapsular network. In other ex-
amples, some branches of the intracapsular arteriolar network reach
the outer 1/3 of the fasciculata along cell cords, passing the sub-
capsular network without branching, then divide into four or five
in a penicillar type, to transfer to venous capillaries (Fig. 8).
3. In the medulla.
Main arterial routes to the medulla are Aa. perforantes (70-90
which directly get there almost perpendicularly to the glandular
surface or at an angle of about 45°, rising from the intracapsular
arteriolar network or the extracapsular plexus. They run in the
corticomedullary zone tangentially to the surface for a short distance,
then enter the medulla as Aa. medullares (35-70g), which soon di-
verge into capillaries (Fig. 9). In general, the perforantes make no
ramifications in the cortex, but in a rare case, give a few branches
(20-40 p) to the cortical parenchyma (Fig. 9).
Further, different types of the perforantes found are as follows :-
1) Some of branches out of the extracapsular arterial plexus or
intracapsular arteriolar network at the dorsal surface, or at times
the ventral surface, get into the medulla subrectangularly to the
surface, without sending out capillaries to the cortex. In the outer
medulla or corticomedullary zone, they run tangentially to the sur-
face, and do not divide into capillaries, but into three or four
branches during their course. One of them spreads into capillaries
to the medulla, the others (60-80 g) recurrently penetrate the cortex
of the ventral side subrectangularly to the surface, and enter into
the subcapsular capillary network, not branching on the way. Some
of them once thicken (120-168 p) at the fasciculata but again abrupt-
ly become thin (ca. 40 ,u) at the glomerulosa (Fig. 1).
2) A branch (192-288 a) from the intracapsular arteriolar net-
work gets inwards, taking a course perpendicular to the surface or
not, regardless of cell cords, and then bends tangentially in the cor-
ticomedullary zone. It gives an extremely few of fine branches to
the medulla, but its main stream pours directly into central veins
or thick veins, keeping its original thickness. In such a case, the
blue-coloured resin injected into the adrenolumbar vein appears on
the glandular surface via the central vein and the perforantes above-
mentioned. Moreover, when the red-coloured resin is injected into
556 H. Okano, Y. Ohta, H. Sawa and I. Fujiwara
the lumbar or inferior phrenic artery, it is guided by branches from
the arteries to supply the gland and is mixed with the blue resin.
This route, after all, is an arteriovenous anastomosis (Figs. 2 and 11),
3) After a branch (170 p) from the extracapsular plexus gives
off two Aa. perforantes (96 g, 120 p) running abreast and subrectan-
gularly to the surface, it becomes thin rapidly (72 p) and enters into
the capsule. Besides, in course of the capsule it divides into three
perforantes (48 au, 36 p, 72 p) at intervals of about 0.6 mm., which run
close in parallel and all are perpendicular to the surface. Accord-
ingly, all Aa. perforantes, five by count, line up in parallel with
one another in a plane (Fig. 12).
Cat :
1. Plexus extracapsularis et Reticulum capillarium infracap-
sulare (s. subcapsulare) (Fig. 13).
Small arterial branches to supply the gland form a plexus (90-
170 p) at the posterior side and marginal region within the adiposal
capsule. It is named Plexus extracapsularis. Many twigs split richly
out of the plexus in the fibrous capsule, but scarcely anastomose
among themselves. No obvious network is found in contrast with
in dog, but right above the capsule fine ramifications become rich.
Branches from the plexus arrive at the subcapsular region and spread
into capillaries running on the surface of the glomerulosa. On the
corrosions, the capillary network is seen corresponding to superficial
spaces of cell cords of the glomerulosa. It is named Reticulum capil-
larium infracapsulare (s. subcapsulare).
Some of branches (72-96 p) arriving at the subcapsular region
from the extracapsular plexus, without ramifying capillaries, curve
in variable depths between the subcapsular region and the outer 1/3
of the fasciculata in their courses, as a series of the arterial loop,
and finally spread into capillaries to the subcapsular rete (Fig. 14).
Occasionally, small arteries (ca. 25 p) , leaving the artery in the fibrous
capsule, enter the cortex and again recur from a depth of about 150
to the subcapsular capillary network (Fig. 18).
2. In the cortex.
Branches from the subcapsular network, anastomosing richly,
twine around cell cords of the glomerulosa and transfer to venous
capillaries in the outer 1/3 of the fasciculata. Any definite glomeruli
(Gefassknduel by J. A r n o l d) are not found in the glomerulosa. But,
some of capillaries in the glomerulofascicular junction recur to the
Vascular System of Suprarenal Gland in Dog and Cat 557
capsule.
3. In the medulla.
Aa. perforantes (60-80 ,u) from the extracapsular plexus get to
the medulla perpendicularly to the glandular surface, and show an
intense meandering in the corticomedullary boundary zone, before
entering into the medulla to supply it (Figs. 20 and 21), dividing
themselves into capillaries. Aa. perforantes generally do not ramify
in the cortex but a few branchings in some cases are seen to be as
follows : 1) small branches (15-28 ,a) in the superficial of the cortex
(Figs. 15 and 16), and 2) a small branch (ca. 26 p) subrectangularly
in the fasciculata or reticularis (in the deep cortex) (Fig. 19).
Following arteries are found as different types of the perforantes :
1) A thick arterial branch (120-150 p,) out of the extracapsular
plexus of the dorsal side penetrates perpendicularly to the surface
into the corticomedullary boundary zone and runs tangentially for a
short distance, then again penetrates the cortex perpendicularly to
the surface and comes out of the fibrous capsule into adiposal tissues
of the ventral side. In short, its course is in an U-shape. On its
way in the cortical parenchyma, several branches (40-60 ,a) are origi-
nated to ascend to the subcapsular region, where they curve to a
tangential direction, and then send off capillaries to supply the glom-
erulosa, while capillaries from the bottom part of the U-course supply
the medulla (Fig. 3).
2) Some of branches (120-160 A) from the extracapsular arterial
plexus penetrate the cortex perpendicularly to the surface. In the
medulla it pours into the central vein or its thick veins. In this
case, the blue-coloured resin connects everywhere on its course, with
the red-coloured resin (Fig. 22). This perforans is thicker than the
ordinary.
B. Venous system
Dog :
Venous capillaries in the capsule, forming a capillary network
without gathering capillaries from the glomerulosa, collect into venules
which anastomose occasionally with arterioles in the capsule, and
then leave it (Fig. 23).
In the cortex, venous capillaries, beginning at the outer 1/3 of
the fasciculata, run towards the medulla, all in parallel with cell
cords. These capillaries show few anastomoses among themselves,
and send off many collateral twigs in their way towards the
558 H. Okano, Y. Ohta. H. Sawa and I. Fujiwara
reticularis making rich anastomoses and show a dense network
medullawards. They abruptly gather into thick venous sinuses in the
corticomedullary zone.
In the medulla, two origins are found, veins from the cortical
parenchyma and veins from Aa. perforantes. Sinuses rising at the
corticomedullary zone are in various • and irregular shapes (Figs.
24 and 25). Great variations in thickness are found between thick
portions (ca. 80 a) and fine portions (ca. 25 p). The sinuses or medul-
lary sinusoids mostly empty into. large branches of the central veins
directly, without intermediating any fine routes.
Cat :
Venous capillaries originate in the outer 1/3 of the fasciculata
and proceed to the medulla. They make few anastomoses in the fas-
ciculata, but repeat anastomoses among their collateral twigs in the
reticularis. As another route, venous capillaries risen from arterial
capillaries at the inner glomerulosa, ascend in the cortex subrectan-
gularly to the capsule and form a venous capillary network anastomo-
sing among themselves. The network gathers to a thick venous
branch, which reaches the adiposal tissue beyond the capsule, then
make extracapsular venous network in a layer.
When the venous branches attain the medulla, they do not ab-
ruptly empty into thick sinuses, but gradually with capillaries in
the medulla gather into thick venous branches (Figs. 28 and 29). In
an exceedingly few cases, a venous branch which rises from the
periglandular region, penetrates the cortical parenchyma into the
medulla and pours directly into the central vein. This is nothing
but V. perforans (Figs. 26 and 27).
Summary and Discussion
On the circulation of the suprarenal gland, opinion is yet divided.
In the early time, M 0 11 e r (1834) and Nagel (1836) state that
arteries penetrated the capsule, divide into capillaries in the glom-
erulosa, and the capillaries run inwards to pour into central veins
in the medulla, then the veins leave the gland. On the contrary Fr.
Arnold (cited by J. Arnold 1866) describes another circulation
taking part with only in the superficial layer of the cortex, that
is, some of capillaries in the cortex proceed to the innerside and
the others run to the outerside " umgekehrt."
Afterwards, Flint and other scholars have denied the A r n o 1 d's
Vascular System of Suprarenal Gland in Dog and Cat 559
circulation, but Hayashi ('56, cat) and Nishina (dog, cat, cattle
and rabbit) mention of a route which gets back to veins in the cap-
sule from vessels in the glomerulosa. Moreover, they have a belief
that such two different circulations in the glomerulosa and fasciculata
respectively, give a suitable substantiation for the dualism of the
cortical hormones by Deane et al. ('46).
The present authors do not oLserve such special circulating route
taking part only in the glomerulosa in dog, but in cat, and observe a
route which gets back to veins in the capsule from the innerside
of the glomerulosa. In case of the acrylic resin injection, the resin
through the artery is often interrupted at the inner glomerulosa
and the one through the vein also at the inner 1/3 of the fasciculata.
Accordingly, on this corrosions, an empty space is produced between
the glomerulosa and fasciculata. In cat, Bennett et al. describe
that the injection fails to pass the barrier of the narrow vessels of
the outer fasciculata, and these constricted vessels characterize the
area thought to be secretory zone of the cortex, where the cells are
so distended with lipoid that they compress the capillaries surrounding
them. Lev e r ('52) also states, supporting the Bennet t's descrip-
tion, that sections treated by F 1 e m m i n g's method show the major
distribution of lipoids to be in the outer layer of the fasciculata and
also in the glomerulosa. Recently, N i c a n d e r ('52) observes the
intermediate zone in dog. The empty space in most cases by the
authors, though filled with indian-ink, seems to correspond to the
characterized zones above-mentioned.
Flint mentions, in dog, no anastomosis among the distributed
arteries until they reach the gland. On the corrosions by the authors,
a few anastomoses are found, though their branchings are much re-
peated. On the feature of the cortical capllaries, J. Arnold and
Nishina describe " capillary glomerulus in the glomerulosa. Al-
most of the predecessors, however, have denied it, and the authors
fail to find it.
Arterial branch from the intracapsular arteriolar network in dog,.
divides into capillaries in the fasciculata without branching beneath
the capsule. On such arterial branch, Flint also mentions that
ultimate arterioles from the capsule sometimes pass through the
glomerulosa and break up into capillaries in this zone.
On Aa. perforantes (s. medullae) in dog, Flint and other scholars
have a view that during the passage of the arteries through the
cortex, they do not divide nor supply any part of the cortical
5€0 H. Okano, Y. Ohta, H. Sawa and I. Fujiwara
substance and are distributed to the medulla, dividing into capillaries
within it. The authors' observations on this point are generally in
accord with their results, but in some cases, small branches which
originate from the perforantes in the cortex to supply it, are observ-
ed. Moreover, three types of interesting variations are observed :
1) The perforans which passes through the corticomedullary
boundary zone tangentially, branches off several twigs outwards and
they enter the intracapsular arteriolar network or subcapsular capil-
lary network.
2) The perforans entered the medulla pours directly into the
central vein or its thick veins without dividing into capillaries.
These examples are thicker than the ordinary perforantes and other
different types. While, when the resin is injected into both vein and
artery, the resin into the vein communicates with that into the artery
in every zone or adiposal tissue, and it is always thicker in the venous
side. In other word, this route evidently pierces the gland. Accord-
ingly, it is considered that Nish i n a may regard the A. perforans
in this type as V. perforans.
3) One branch from the extracapsular arterial plexus divides
in a fork shape to five perforantes in a plane.
In cat, Bennett describes that Aa. perforantes undivide into
capillaries even if dichotomizing in the cortex. The present authors
also ascertain the fact. However, in some cases, the perforantes
which send off a small branch in the superficial of the cortex or in
the fasciculoreticular junction are observed. Besides, other variable
types are also observed :
1) The perforans, out of the extracapsular plexus of the dorsal
side, once getting in the corticomedullary zone, runs tangentially to
the ventral side of the gland, and again penetrates the cortex to
the adiposal capsule, and on the way it sends out small branches to
both cortex and medul:a. This type is considered to correspond to
the type 1) of dog. It is considered that, in dog and cat, an
arterial branch which penetrates the gland to the ventral side is
surely existent as a route to that region in addition to the arterial
branches from environs of the gland, because the extracapsular
arterial plexus lacks in that region.
2) A branch from the extracapsular plexus penetrates the
cortex to the medulla, wbe:e it pours into the central vein or its
thick veins. Such perforantes found in both animals may be consi-
dered, when the blood press-„re to the gland rises, the blood velocity
Vascular System of Suprarenal Gland in Dog and Cat 561
pouring into the central vein directly through them increases, and
pulls out the venous blood in sinuses of the medulla to the adrenolum-
bar vein.
3) On the tortuosities of the perforantes in the corticomedullary
junction, Bennett suggests that these twistings might very well
provide for a ready lengthening of the artery whenever the gland
expands. Recently, Selye publishes in rat, that hypertrophy of the
cortex, especially of the fasciculata and reticularis, takes place in
case of the general adaptation syndrome and alarm reaction.
V. perforans observed in cat by the authors has no relation to
the blood circulation within the suprarenal. N i s h i n a describes
the V. perforans in dog, but that by Omura ('54) is a route which
receives blood in the cortex and carries it to the capsule. The
present authors are perplexed as to functions of the latter.
The arterial loop, proceeding shallowly or deeply in the cortex
in wave like manner and gets back to the capsule, is already reported
by Bennett et al.
Conclusions
1. Vascular system in the suprarenal glands of dog and cat is
studied by corrosion specimens injected with the acrylic resin and
the indian-ink injected sections.
2. Arteries supplying the gland make at first Plexus extra-
capsularis in the adiposal tissue. Arteries from the plexus make
Rete intracapsulare in the fibrous capsule in dog, but not in cat.
Branches from the rete or the plexus spread into capillaries covering
the whole glomerulosa, and the capillaries anastomose among them-
selves richly to make Reticulum capillarium infracapsulare (s. sub-
capsulare).
3. In cat, some of branches arriving at the subcapsular region
from the extracapsular plexus without dividing into capillaries, rise
and fall in variable depths between the subcapsular region and the
outer 1/3 of the fasciculata. Their ends finally spread into capillaries
to the subcapsular reticulum.
4. In dog, branches from the intracapsular rete run inwards
without sending capillaries to the subcapsular reticulum. Entering
the fasciculata, they divide into several capillaries in parallel,
transferring to venous capillaries at the outer 1/3 of the fasciculata.
5. In the cortex, capillaries from the subcapsular reticulum run
562 H. Okano, Y. Ohta, H. Sawa and I. Fujiwara
inwards, twining around cell cords and anastomosing with one another.
Meshes made of capillaries are irregular lattices in the glomerulosa,
and elongated lattices in the fasciculata. Then, they touch to venous
sinusoids at the outer 1/3 of the fasciculata. In cat, some capillaries
in the glomerulosa recur to venules in the capsule.
6. Main arterial sources of the medulla are Aa. perforantes
originated from the extracapsular plexus or intracapsular rete. In
general, their branching in the cortex is not observed. In some
cases, however, the perforantes give small branches to the cortex in
the superficial and fasciculoreticular junction. In cat, the perforantes
show spiral courses in the corticomedullary junction.
7. The following different types of the perforantes are observed :
i) In dog, A. perforans out of the extracapsular plexus in the
dorsal side of the organ runs inwards nearly at a right angle against
the capsule to the corticomedullary junction and passes there to the
ventral side, then divides into 3-4, one of which spreading into
capillaries to the medulla, the others penetrating perpendicularly
the cortex to the subcapsular rete as capillaries.
ii) An artery from the extracapsular plexus divides in a fork
shape to five perforantes in a plane in dog.
iii) In both animals, some of Aa. perforantes pass through the
cortex to the medulla and pour into the central vein or its thick
veins directly. Such perforantes may play a function to draw out
the venous blood in the sinus of the medulla.
iv) In cat, A. perforans from the extracapsular plexus in the
dorsal side of the organ perforates the cortex to the medulla. In
the corticomedullary_ junction, it bends parallel with the surface and
goes round to the ventral side of the gland. Then, it turns upwards
at a right angle to the surface and again passes through the cortex
to the adiposal tissue. During its course, it gives branches to the
cortex and medulla.
8. No V. perforans is observed in dog, and some of Aa. per-
forantes, without spreading into capillaries, empty into the central
vein or its thick veins with their original thicknesses. It might be
that these arteries are regarded as Vv. perforantes by some previous
scholars. In cat, Vv. perforantes are originated in the periglandular
region and pour into the cental vein penetrating the cortex.
9. Capillaries entering the medulla from the cortex and capil-
laries from Aa. perforantes collect to sinusoids or sinuses abruptly,
and empty into the central vein in dog ; but gradually collect in cat