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Morpho-histological investigation of kidney of bactrian camel (Camelus bactrianus)


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Morphological characteristics of the kidneys in the two-humped camels were investigated using the anatomical and histological methods. The 2 kidneys in the camel contributed about 0.6% of the body weight. The ratio of thickness of the renal medulla to the cortex was 4:1, which indicated that Henle’s loops in camel’s kidneys were very long. In cortex, there were more juxtamedullary nephrons and mid-cortical nephrons which had longer Henle’s loops. Proximal convoluted tubules were far longer than the distal ones. In the outer medullary zone, the vasa recta were grouped obviously into specific vascular bundles which alternated with the bundles of Henle’s loops and collecting tubules. The inner medullary zone was thicker than the outer one. Specialised fornices were formed by projecting of either side of the pelvis and extended between renal pyramids to medullary outer zone where second pyramids clearly occurred. The characteristics above showed that kidneys in bactrian camels possessed a strong reabsorption and hence promoting the production of high concentrated urine.
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Journal of Camel Practice and Research December 2009 / 1
The two-humped camel has high ability that can
endure thirst and produce high concentrated urine.
Experiments have demonstrated that the camel is not
in danger even it loses body fluid up to the 30% of the
total body reserves. There are very few references
available regarding the water metabolism in two-
humped camel body, and more inferential
explanations (Shui, 1990) within the references rather
than objective evidences. In recent years, there have
been some studies on physiology and biochemistry of
water metabolism and its regulatory factors in camel.
Because the two-humped camel has higher blood flow
through the kidneys and more osmotic pressure which
ensures the reabsorption of water and retains alkaline
reserves, these are the important functions that could
ensure the regulation of the blood acid-base balance
in the shortage of water, maintain blood volume, and
ensure the normal water metabolism in body (Xiang et
al, 1997). Antidiuretic hormone and aldosterone were
the important factors which regulate the water
metabolism and urinary output in two-humped camel
(He et al, 1999). There is difference between the arterial
supply to the two-humped camel’s kidney and other
animals (Chen and Liu, 2000). In case of water
shortage, camel can excrete high concentrated urine to
reduce the water loss and can drink salty water which
contains fairly high salt concentration (Zhao, 1995).
This paper describes morphological and histological
features of the two-humped camel’s kidney.
Materials and Methods
Ten adult healthy male and female two-humped
camels from pasturing area of Inner Mongolia Ala
Shan You Qi, one of the aridest areas in China, were
used in this study.
All protocols were approved by the Chinese
Committee for Animal Use for Research and Education.
The individuals were anaesthetised with an
intraperitoneal injection of sodium pentobarbital and
killed by cervical blood-letting. Their kidneys were
weighed and 10 integral kidneys were fixed in the 10%
of formaldehyde solution for morphological
observations and the relevant data were measured bya
sliding caliper. Another 10 fresh kidneys were used
for histological observations. Many slides were
papered from the upper, middle and deeper sections
of cortex, and the medulla from the centre of the kidney,
and then were fixed in the 10% of formaldehyde
solution. The size of these pieces was 8mm×4mm×
1mm. Paraffinised sections were then stained with H
Galley Proof-4
Vol 16 No 2, p 1-6
KIDNEY OF BACTRIAN CAMEL (Camelus bactrianus)
Chun-sheng Xu1,2, Hui-jun Bao1, Feng-Hua Qi2, Yi Liu1, Jun-hui Qin1,
Jameel Ahmed Gandahi1, Qiu-sheng Chen1
1College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095
2Shihezi University, Shihezi 832003, PR China
Morphological characteristics of the kidneys in the two-humped camels were investigated using the
anatomical and histological methods. The 2 kidneys in the camel contributed about 0.6% of the body
weight. The ratio of thickness of the renal medulla to the cortex was 4:1, which indicated that Henle’s loops
in camel’s kidneys were very long. In cortex, there were more juxtamedullary nephrons and mid-cortical
nephrons which had longer Henle’s loops. Proximal convoluted tubules were far longer than the distal ones.
In the outer medullary zone, the vasa recta were grouped obviously into specific vascular bundles which
alternated with the bundles of Henle’s loops and collecting tubules. The inner medullary zone was thicker
than the outer one. Specialised fornices were formed by projecting of either side of the pelvis and extended
between renal pyramids to medullary outer zone where second pyramids clearly occurred. The characteristics
above showed that kidneys in bactrian camels possessed a strong reabsorption and hence promoting the
production of high concentrated urine.
Key words: Bactrian camel, high concentrated urine, histology, kidney, morphology
Please Checked by
Figs 1,2,3,4,5,6,7
Tables 1,2,3,4,5,6.7
Journal Names
Author e-mail
2 / December 2009 Journal of Camel Practice and Research
& E. Olympus microscope was used to observe and
photograph the slides, and the data were measured by
micrometer ruler.
Morphological observations
The left and right kidneys of the two-humped
camel appeared fabiform-like, with smooth surface (Fig
1). The average size of left kidney was 19 cm×14 cm×9
cm, and the right one 18 cm×14 cm×8 cm. The total
weight of two kidneys was 3.0 kg, accounting for 0.6%
of its body weight. In a cross section of the fixed kidney
specimen, the boundary between the cortex and the
medulla was obvious. The cortical colour was light
while the medullary colour was bright. The junction
of the cortex and medulla was serrated, and the
average thickness of the cortex was 4 times that of the
medulla. The medulla was further divided into light
colour medulla interna and bright colour medulla
externa. The thickness of medulla interna was two
times to the medulla externa. The medulla was
composed of 11 or 12 renal pyramids. The pyramidal
nipples merged mutually to form crystal across renal
pelvis. A distinct secondary renal pyramid was formed
in the side-bottom of the adjacent renal pyramid. The
bases of these pyramids were towards the cortex while
the apices were towards the medulla interna. The
secondary renal pyramid in the kidney lateral edge
was particularly obvious (Fig 2). The renal pelvis was
the intumescent segment of the cranial part of the
ureter which was located in the renal sinus.
Eliminating the renal parenchyma, about 10 or 11
protuberant mucous folds could be seen. The folds
were radiated from the dorso-ventral side of the renal
pelvis, and stretched to the medulla externa among the
renal pyramids. The correspondent dorso-ventrum of
renal pelvis protruded into the boundary of the
medulla interna and the medulla externa, connected
to each other and formed fornix structure. This is the
secondary renal pyramids located at the convex
surface of the fornix structure. The renal sinus was
filled with adipose tissue, and the ureter, renal artery
branches and renal vein tributaries passed through it.
The ureter debouched behind the 1/3 of renal pelvis.
Before it entered into renal hilus, the renal artery had
been divided into two dorsal and ventral branches. The
tributaries of the renal vein merged and left away from
the renal hilus.
Histological observations
The renal capsule was composed of dense
connective tissue. In its deep stratum, lamellar smooth
muscle fibres could be seen distinctly. The cortex was
composed of cortical labyrinth and medullary rays. The
cross-section quantity of the proximal convoluted
tubule in cortical labyrinth was more far than the distal
convoluted tubule (20:1) (Fig 3). The brush border of
the proximal convoluted tubule was well developed.
The renal corpuscles were distributed in the central
cortex section and cortico-medullary junction, but
below the capsule in the range of 1000 to 1500 µm, no
renal corpuscles found (Fig 4). The quantity of the
juxtamedullary nephrons and the intermediate
nephrons was much more than that of the superficial
nephrons. In cortex, the density of the renal corpuscle
was 115/mm2, so it was sparser. There were
differences between the size of the renal corpuscles of
superficial nephrons and the juxtamedullary ones. The
diameter of the former was 200 to 220 µm (external
diameter of Bowman’s capsule) and 190 to 210 µm
(diameter of glomerulus), and the latter was 260 to 280
µm and 250 to 270 µm, respectively. Medullary rays
broadened out gradually from the capsule to the
cortico-medullary junction, containing the parallel
uriniferous tubule and plenty of capillaries. In cortex,
the blood capillaries kept tightly close to the renal
tubules and the distribution was very rich among them,
and it occupied the most of renal interstitium.
The medulla could be differentiated into medulla
externa and medulla interna. The vasa rectae in the
medulla externa was well grown. Under the cortical
labyrinth, it extended and formed wide vasa rectae
bundles. The latter were arranged alternatively with
the uriniferous tubule bundles of the cortical medullary
rays. The width of the vascular bundle was nearly
equal to that of the uriniferous tubule bundle. Inside
the vascular bundle, the thin segment of the renal
tubule was not seen (Fig 5).
The dissepiment of vasa rectae was very thin.
From the superficial layer of the medulla externa
(medulla side of arcuate artery), the change of the
simple cuboidal epithelium lining the descending limb
into simple squamous epithelium lining the thin
segment of the descending limb of Henle’s loop was
clear (Fig 6).
In a cross section of the medulla interna,
collecting ducts, thin segments of the descending limbs,
pars rectae as well as many blood capillaries among
them could be observed (Fig 7). Sometimes, the small
funiculose vessels could also be seen. The wall of the
collecting tubule is built of regular simple cuboidal
epithelium. Its cell cytoplasm was bright and the
boundary was clear. The tubal wall of pars recta was
formed of low simple cuboidal epithelium, the
cytoplasm was addicted to eosin and the boundary
was unsharpened.
Journal of Camel Practice and Research December 2009 / 3
In the papillary segment of the medulla interna,
the interstitial tissue became increasing; the papillary
duct was obvious, with epithelium increasing in height
and changed into the simple columnar type. The cells
were bright and the boundaries were clear. There was
much thinner segment of Henle’s loop and blood
capillaries between papillary ducts (Fig 8).
Animals (such as Meriones unguiculata,
Macropus, African wild donkey, desert goat and sheep
etc.) which inhabit the arid or environments with
water shortage for a long time, or were accustomed to
drink salty water or eat high salty food, have the ability
of excreting high concentrated urine. However, animals
(such as Sus scrofa domestica, Wildebeest and
bedfordiae etc.) which inhabit the moist climate or the
regions with adequate water supply, generally, excrete
more diluted urine. These properties must be relevant
with the thickness of kidney medulla. The proportion
of thickness of the medulla and cortex was 5:1 in
Meriones unguiculata, Macropus, African wild
donkey, and it was 3:1 in desert goat and sheep, where,
the medullary portion was broad. However the
proportion of the thickness of medulla and cortex was
1:5 in Sus scrofa domestica and bedfordiae and 1:1 in
Wildebeest. The medullas of these animals were
relatively narrow (Mbassa, 1988). The proportion of
Fig 1. External morphology of the camel kidney. Formalin
fixed. Left kidney (L). Right kidney (R). Renal artery
(). Renal vein ().
Fig 2. Frontal plane of the kidney. Formalin fixed. Cranial
(Cr). Caudal (Ca). Dorsal half (D). Ventral half (V).
Cortex (C). Medulla (M). Secondery pyramid (). Renal
pelvic projection (). Fornix (). Pelvic (). Renal
sinus ().
Fig 3. Cortical labyrinth. Corpuscula renis (). H&E. Bar
=2.5 µm Fig 4. Proximal convoluted tubule (Pt). Distal convoluted
tubule (Dt). H&E. Bar = 0.25 µm
4 / December 2009 Journal of Camel Practice and Research
thickness of the medulla and cortex was directly
proportional to the relative length of Henle’s loop, the
larger the proportion, the longer the Henle’s loop; and
vice versa. Long Henle’s loop was helpful for
establishing higher osmotic pressure gradient in the
medulla, then forming high urinary concentration, and
also it could reduce the loss of water in urine. The
proportion of thickness of the medulla to cortex was
4:1 in the two-humped camel. This could be speculated
that the Henle’s loop was longer in the former.
Moreover, this confirms that the medulla of the two-
humped camel have morphological basis to form high
osmotic pressure gradient.
The distribution of renal corpuscles could not
be observed till a distance of 1000 to 1500 µm beneath
the renal capsule of two-humped camel in present
study. Nephrons in the central and deep cortices were
distributed widely, but in the medulla interna and
renal papilla we could see plenty of thin segment
sections. This indicated that short loop nephrons of
the two-humped camel were very few, the majorities
were juxtamedullary nephrons and long loop middle
nephrons, and its thin segment was long too. Animals
which come from the arid region (such as meriones
unguiculata and small meriones unguiculata etc.) had
more juxtamedullary nephrons and middle nephrons,
Henle’s loop and its thin segment was longer, and
normally they excrete highly concentrated urine
(Valtin, 1977).
The surface of proximal convoluted tubule had
Fig 5. Cortex. Capsule (). Cortical labyrinth (). H&E. Bar
=2.5 µm. Fig 6. Outer zone of medulla (longitudinal section). Vascular
bundle of vasa rectae (). Uriniferous tubule bundle
(). H&E. Bar =2.5µm.
Fig 7. Outer zone of medulla (cross section).Vascular bundle
of vasa rectae (). Uriniferous tubule bundle ().
H&E. Bar =2.5µm.
Fig 8. Inner zone of medulla. Thin segment (arrows).
Collecting tubule (Ct). H&E. Bar =1µm. These Figures
above had been checked.
Journal of Camel Practice and Research December 2009 / 5
brush border which increased the absorptive surface
area largely. About 70-80% of moisture in the original
urine was reabsorbed again here. Beliveau and
Bruneter (1984) guessed that animals inhabiting the
arid area should have longer proximal convoluted
tubule, and it was shorter comparatively in animals
inhabiting abundant water source. However, there was
no enough morphological evidence to support this
view. In the present study, the most of renal tubule
sections in the renal cortex were proximal convoluted
tubule with well grown brush borders, and distal
convoluted tubules were seldom. This demonstrated
that proximal convoluted tubule of two-humped camel
was long enough, so it has more power than other
animals to absorb original urine.
The renal vein of the camel is unique and is
different from other domestic animals, it could be
related to with high concentrated urine production
(Saber, 1987). In the present study, in was observed
that the blood supply of two-humped camel kidneys,
was abundant, and the relationship between the
uriniferous tubules and blood vessels is very close. It
might be helpful to promote the movement of
substance contained in urine between uriniferous
tubule and blood vessel. Stephenson et al (1976)
emphasised that the uriniferous tubules and blood
vessels were integrated functionally, instead of treating
them as 2 isolated sections. After exit of the efferent
glomerular arterioles of the juxtamedullary nephrons
from the renal corpuscle, it formed straight arterioles
and descended into the medulla in different depths,
and returned into interlobular veins or arcuate veins.
Therefore, it would form a lot of “U” shape blood vessel
loops in the medulla. In some of animal’s kidney
which could produce highly concentrated urine, the
vasa rectae assembled and formed special blood vessel
bundles out of the medulla externa. These blood vessel
bundles were arranged alternatively with the
uriniferous tubule bundles formed by the straight
segments of the Henle’s loop and collecting ducts.
Kaissling et al (1975) believed that the short loop
nephron, mixed with thin segment of vasa rectae was
a typical structure of small desert animal kidneys.
Moreover, they pointed out that macrofauna living in
arid environment with few water supply lacks this
kind of structure. In the present study, we observed that
the arrangement of the vasa rectae in the two-humped
camel’s kidney was very special, which assembled and
formed obvious vascular bundles in the medulla, and
arranged alternately with the uriniferous tubule
bundles. In the medulla externa, this kind of vascular
bundles was particularly broad. Being different from
small-sized desert animals, and in contrary to the
standpoint of Kaissling et al (1975), the distribution of
the thin segment could not be seen in the vasa rectae
of the two-humped camel’s kidney. The alternative
arrangement mode of rectiserial Henle’s loop and
uriniferous tubule was the important factor for
reabsorbing the moisture in original urine and
exchanging the other substance, and then producing
high concentrated urine (Jones and O’Morchoe, 1983).
However; in two-humped camel kidney, the
medulla interna was well grown. The renal pelvis gave
off mucous prominences from the ventro-dorso and
stretched to the medulla externa, and formed distinct
secondary pyramid. This demonstrated that the renal
pelvis of the two-humped camel belongs to the model-
II renal pelvis, and is responsible for the ability of
producing high concentrated urine. The appearance
of the advanced medulla interna, renal pelvis
projections and secondary pyramids was helpful to
produce the highest concentration gradient in the
medulla, and then concentrated urine in desert rodent
(Barret et al, 1978).
The kidney weight and its ratio to the body
weight were different in different species. The kidney
weight of rabbits, pigs, humans, horses and oxen was
18-24g, 400-500g, 300g, 900-1500g and 1200-1400g,
respectively. The percentage of the kidney’s weight to
the body weight was 0.6%-0.7%, 0.5%-0.6%, 0.4%,
0.29%-0.39% and 0.2%, respectively (Tian, 1993 and
Cheng, 1994). Generally, the bigger the animal's
physique, the smaller the ratio, and vice versa. There
was an inverse proportion between the physique and
the percentage. However, the physique of the two-
humped camel was bigger and its percentage was
nearly the biggest (0.6%). It points to the ability of
kidney of two-humped camel in handling urine.
This research was funded by the grant (No.
39500109) from the National Science Foundation of PR
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... The water conservation ability of mammalian kidney has been estimated from the size of the renal pelvis (Abdalla, 2020), the value of the relative medullary thickness (Al-kahtani et al., 2004), the extent of the renal crest (Kriz and Kaissling, 2008) and the ratio of the medullary to cortical thickness (Xu et al., 2009). In the present study, the renal pelvis was small and not as elaborate as that of the dromedary camel, as reported by Abdalla (2020). ...
... Conversely, Abdalla (2020) observed extensive renal crest in the arid habitat-dwelling camels. Furthermore, Munkácsi and Palkovits (1977) reported a ratio of medullary to cortical thickness of 6: 1 in the desert kangaroo, while Xu et al. (2009) recorded 4:1 in the Bactrian camel. These are evidence of thicker medulla than cortex in the desert animals. ...
... Correspondingly, it is expected that the renal size will not be significantly different. Xu et al. (2009) reported a renal volume of 2,394 cm 3 (from average size of 19 cm×14 cm×9 cm) and 2,016 cm 3 (from average size of 18 cm×14 cm×8 cm) for the left and right kidney of the Bacterian camel. This is comparable to the renal volume of 2146 cm 3 and 1895 cm 3 observed for the left and right kidney, respectively, in the giraffe in the present study. ...
... However, many studies carried out on different mammalian species have shown remarkable controversy in the histological structure of the two layers forming the renal capsule, particularly the amount of the capsular connective tissue fibres and smooth muscles. In addition, several studies indicated the variation in the total thickness of the renal capsule of different animals (Bulger et al., 1979;Mbassa, 1988;Xu et al., 2009;Singh, 2013;Sikarwar et al., 2016). Search in the literature revealed that only few studies have been carried out to compare the renal capsule of different animals (Kobayashi, 1978 ...
... The current study showed that, the kidneys of the three species were covered by connective capsule composed of outer and inner layers. Similar findings were reported by Abdalla (1973), Xu et al. (2009) andSingh (2013). In camel, the present investigation showed that the inner layer had scattered smooth muscle fibres. ...
... The presence of such muscle fibres was confirmed by their positive PAS basement membranes. This is in agreement with the previous accounts given by Abdalla (1973) and Xu et al. (2009) (2000) in domestic animals who reported the presence of smooth muscles within the renal capsule. Furthermore, smooth muscle fibres were also reported in human and experimental animals (Gartner, and Hiatt, 2007;Al-Samawy, 2012;Al-Jebori et al., 2014). ...
Full-text available
Kidneys from adult she camels, cows and ewes (eight from each) were investigated using histologic and histometric techniques to study the renal capsule. The capsule in the kidney of the three species was made up of two layers, outer and inner. The outer layer of the renal capsule was composed mainly of dense collagenous fibres arranged in wavy bundles. The outer layer was the thicker in she camel (396 µm) as compared to cow (39 µm) and ewe (36 µm). The outer layer represented about 82% of the total thickness of the capsule in she camel and cow whereas it was only 37% in ewe. The inner layer in the three species was mainly formed of smooth muscle fibers, and fine collagen and reticular fibres. The reticular fibres in the inner layer of the renal capsule were markedly extensive in ewe and cow compared to she camel. Smooth muscle fibres formed a distinct thick layer in ewe and a thin one in cow; however, in her camel they were randomly distributed. No elastic fibres were present in all capsules studied. The inner layer was observed to be thick in ewe as it constituted about 63% (61.2 µm) of the total thickness of the capsule compared to only 18% in both cow (8.4 µm) and she camel (84.3 µm). The study revealed that the renal capsule was thickest in she camel (480.4 µm) compared to ewe (97.5 µm) and cow (47.3 µm). It is concluded that the renal capsules of she camel, cow and ewe showed remarkable variation in thickness as well as the amount of the histological components. It is suggested that such variation might influence the function of the renal capsule.
... The general histomorphological findings of the present study were similar to those reported in previous investigations on the camel (Abdalla and Abdalla, 1979;Beniwal et al., 1998;Wenhui and Huaitao, 2000;Xu et al., 2009). Furthermore, the present study confirmed that the renal histology of the camel does not differ significantly from other mammalian species, such as the dog (Bulger et al., 1979), cattle (Mbassa, 1988), and sheep (Singh et al., 2018). ...
Full-text available
Intermediate filaments belong to a large family of proteins which contribute to the formation of the cytoskeleton. The immunolocalization of cytoskeletal proteins has been used extensively in the diagnosis of various renal pathologies. The present study described the immunolocalization of the cytoskeletal proteins vimentin, desmin, smooth muscle actin, and cytokeratin 19 in the normal kidney of the dromedary camel. Kidney samples from eight adult camels were processed for histology and immunohistochemistry. The kidney was enclosed in a renal capsule composed of vimentin immunoreactive fibroblasts and smooth muscle actin immunoreactive smooth muscle cells. The smooth muscle cells in the renal capsule did not exhibit desmin immunoreactivity. Podocytes forming the visceral layer of the glomerular capsule were immunoreactive for vimentin. Immunoreactivity for vimentin and smooth muscle actin in the parietal layer of the glomerular capsule varied, with both reactive and non-reactive cells observed. Intraglomerular mesangial cells were immunoreactive for smooth muscle actin and desmin, but non-reactive to vimentin. The endothelial lining of blood vessels was vimentin immunoreactive, while smooth muscle actin and desmin were demonstrated in the smooth muscle cells of the vessels. The thin limbs of the loops of Henle in cortical nephrons displayed vimentin immunoreactivity. The proximal and distal convoluted tubules, as well as the collecting ducts were negative to vimentin, smooth muscle actin, desmin and cytokeratin 19 immunostaining. In conclusion, the present study has revealed that similarities and differences exist in the immunolocalization of cytoskeletal proteins in the camel when compared to other mammals. The presence of smooth muscle actin in the parietal cells of the glomerular capsule suggests a contractile function of these cells. The results of the study indicate that vimentin and smooth muscle actin can be used as markers for the identification of podocytes and intraglomerular mesangial cells, respectively, in the camel kidney.
... The kidneys of all the camels (100%) examined had microscopic lesions which manifested grossly in only two camels (2.4%). The lesions were abnormal structures not associated with normal camel kidneys (Safer et al., 1988(Safer et al., , 1991Xu et al., 2009). This is evidence that subclinical kidney pathological conditions may not manifest grossly among the camels at necropsy (Aughey and Frye, 2001). ...
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Kidney lesions of dromedary camels were investigated in an observational cross-sectional survey in an abattoir in Maiduguri, Nigeria (January to March, 2017). The kidneys of 82 camels were collected after slaughter for gross and microscopic examination in order to identify lesions. The kidneys of two (2.4%) camels exhibited gross lesions with either pyo-nodular or granular subcapsular lesions which represented localized acute purulent interstitial nephritis or chronic fibrosing lyphoplasmocytic interstitial nephritis, respectively. The kidneys of 80 (97.6%) out of 82 camels with no apparent gross lesions had microscopic lesions in all the kidneys (100%). The microscopic lesions among all the camels (and their frequencies) were renal tubular degeneration and necrosis (100.0%), acute (13.4%) or chronic (6.1%) interstitial nephritis (19.5%), interstitial fibrosis (6.1%), proliferative (4.9%) or membranous (9.8%) glomerulonephritis, membranoproliferative glomerulonephritis (1.2%) and glomerular atrophy (23.2%). In conclusion, kidney lesions were infrequently recognised as gross lesions among the dromedary camels, but microscopic lesions were commonly encountered as nephrosis or nephritides, suggesting that renal function assessment might be necessary in the routine dromedary health evaluations in local veterinary practices. Des lésions rénales de dromadaires ont été étudiées dans une enquête observationnelle transversale, dans un abattoir de Maiduguri au Nigéria (janvier à mars 2017). Les reins de 82 chameaux ont été prélevés après l'abattage et soumis à un examen macroscopique et microscopique, dans l'objectif d'identifier la nature des lésions. Les reins de deux (2,4%) chameaux présentaient des lésions macroscopiques, avec des lésions sous-capsulaires pyo-nodulaires ou granulaires qui représentaient respectivement une néphrite interstitielle aiguë purulente localisée ou une néphrite interstitielle lyphoplasmocytaire fibreuse chronique. L'ensemble des reins de 80 (97,6%) des 82 chameaux sans lésions macroscopiques apparentes avaient des lésions microscopiques (100%). Les lésions microscopiques chez tous les chameaux (et leurs fréquences) étaient la dégénérescence et la nécrose tubulaires rénales (100,0%), la néphrite interstitielle aiguë (13,4%) ou chronique (6,1%), la néphrite interstitielle (19,5%), la fibrose interstitielle (6,1%), la glomérulonéphrite proliférative (4,9%) ou membraneuse (9,8%), la glomérulonéphrite membranoproliférative (1,2%), et l'atrophie glomérulaire (23,2%). En conclusion, les lésions rénales étaient rarement reconnues comme des lésions macroscopiques chez les dromadaires, mais des lésions microscopiques étaient fréquemment observées sous forme de néphrose ou de néphrite, ce qui porte à croire qu'une évaluation de la fonction rénale pourrait être nécessaire dans les analyses de routine de la santé du dromadaire dans les cabinets vétérinaires locaux.
... Up to 36 pyramids converge from the dorsal, ventral and lateral regions of the kidney as revealed by dissection and corrosion casts ( Figures. 1, 3, and 4). In the Bacterian camel [34] stated that "the medulla was composed of 11 or 12 renal pyramids". This is far less than those presently found in the kidney of the dromedary camel. ...
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The aim of this study was to report some of the morphological characteristics of the kidney involved in urine concentration and hence water conservation in the dromedaries. A total of 20 fresh kidneys of 10 apparently healthy camels were used in this study. The architecture of the renal pelvis was revealed by dissection and polyvinyl chloride corrosion casts. Samples were also processed for histology and for enzyme histochemistry. The camel kidney is bean shaped, smooth, multilobar, unipapillary, in which the fusion of renal papillae is complete forming a common renal papilla or crest, which channel urine into a central renal pelvis. It is more or less similar to equine, caprine, ovine and canine kidney. Under certain anatomical requisites the renal pelvis is known to play a role in urine concentration through recycling of urea to increase the medullary osmotic concentration which favors the counter-current mechanism. One of these requisites is an elaborate renal pelvis which is closely associated with the renal medulla. The renal pelvis of the camel has a main crescentic cavity following the long axis and curvature of the kidney. A thick extensive renal crest projects into the cavity of the pelvis. The thick renal crest contains large numbers of long loops of Henle and vasa recta which are important for urine concentration. The renal crest is formed by convergence of the medullary pyramids before it projects into the cavity of the renal pelvis. The crescentic main cavity of the pelvis forms 20-24 three dimensional radiating collateral recesses which contain the medullary pyramids. This close association of the renal pelvis and medulla provide a large surface area for the recycling of urea and hence urine concentration. This large pelvic-medullary interface is lined by simple low cuboidal epithelium which enhances the recycling of urea and water from the pelvic urine into the medulla and directly contributes to urine concentration. The rest of the wall of the renal pelvis and its recesses facing away from the renal crest and medullary pyramids is lined by impermeable transitional epithelium. Another feature is the intense activity of alkaline phosphatase demonstrated in the proximal convoluted tubules which indicates increased membrane transport. It is concluded that the kidney in dromedaries has the anatomical and histo-chemical requisites for the production of concentrated urine. These requisites enable the kidney to adequately contribute to the ability of the camel to conserve water and withstand the aridity of its habitat.
... These results will not only provide an understanding of the kidney structure of Bactrian camels and insights into the diversity of species, but are also helpful for further investigations into adaptations to desert climate. gradient which eventually produces hypertonic urine (Xu et al., 2009). The features that help dromedary to survive in deserts are also key factors for the Bactrian camel to reduce water loss; these features are closely linked to the environmental adaptability of the Bactrian camel. ...
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Studies and reports focusing on the Bactrian camels' kidney structure from an anatomical perspective are scanty, therefore, this work aims to systemically investigate the anatomical structure of the kidney and examine the distribution and microstructure of intrarenal arteries. Ten pairs of healthy adult kidneys from male and female Bactrian camels were used in the study. The kidney of Bactrian camel appeared like a broad bean with a smooth surface. Using artery casting, we observed that the renal artery divided into dorsal and ventral branches; the dorsal branch continuously divided into a shorter anterior branch and a longer posterior branch, while the ventral branch directly divided into interlobar arteries. The number of interlobar arteries in the left and right kidneys were slightly different, 14 to 16 in left while 16 in the right kidney. No anastomosis was found between the dorsal and ventral branches or their sub-branches. To further study the microscopic structure, microanatomy and scanning microscope were used. Surprisingly, we observed two other ways afferent arteriole arose apart from the interlobular artery. They were the arcuate artery and conjoint afferent arteriole. Two afferent arterioles supplied one glomerulus and occasionally the absence of glomerulus was also observed, where the arteriole kept extending, and no typical glomerulus formed. Since branching of arteries and urologic function of kidneys are physiologically integrated, these features of Bactrian camel may help to further investigate their adaptations to desert climate.
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Finite difference equations describing salt and water movement in a model of the mammalian kidney have been solved numerically by an extension of the Newton-Raphson method used for the medullary counterflow system. The method permits both steady-state and transient solutions. It has been possible to simulate behavior of the whole kidney as a function of hydrostatic pressures in renal artery, vein, and pelvis; protein and other solute concentrations in arterial blood; and phenomenological equations describing transport of solute and water across nephron and capillary walls. With the model it has been possible to compute concentrations, flows, and hydrostatic pressures in the various nephron segments and in cortical and medullary capillaries and interstitium. In a general way, calculations on the model have met intuitive expectations. In addition, they have reemphasized the critical dependence of renal function on the hydraulic and solute permeabilities of glomerular, postglomerular, and medullary capillaries. These studies provide additional support for our thesis that the functional unit of the kidney is not the single nephron, but a nephrovascular unit consisting of a group of nephrons and their tightly coupled vasculature.
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As other rodent kidneys (rat, mouse), the Psammomys kidney consists of two types of nephrons, 66% short looped and 34% long looped nephrons. In the strongly developed medulla the inner stripe shows the most striking pattern. It consists of two distinct compartements, that of the giant vascular bundles and that of the interbundle regions. The giant vascular bundles consist of about 8 to 14% arterial vasa recta and 39 to 47% venous vasa recta; furthermore they include the thin descending limbs of the short loops of Henle which amount to 44 to 51% of the bundle structures. The tubules of the interbundle regions surround the bundles in a regular pattern. The possible functional importance of the described specializations of the Psammomys kidney (giant vascular bundles, large inner zone, special shape of the renal pelvis) for the urine concentrating and urea recycling mechanisms is discussed.
Since the anatomical descriptions of Bowman showing differences between nephrons originating in the superficial and deep cortex, the concept of heterogeneity has been extended from identification of dissimilarities between nephrons to recognition of inhomogeneity within major portions of individual nephrons. We are now aware of functional correlates for the anatomical differences between nephrons, between analogous parts of different nephrons, and between the three portions of the proximal tubule and the three or more parts of the distal tubule. The implications of all of these differences for major renal processes, such as isosmotic fluid transport, salt balance, hypertension, urinary acidification, and the concentration or urine are now being defined. It seems likely that new conceptual and technical approaches, especially electron probe microanalysis, will add appreciably to defining the role of heterogeneity in these and other processes. Despite the increasing complexity of nephron heterogeneity, it is recommended that our basic nomenclature be retained and that new findings be incorporated into the schema set forth by Karl Peter. It would be very helpful if reports of investigations on single nephrons or segments of nephrons were to include diagrams delineating the structures on which the work was performed.
Long nephrons are derived from juxtamedullary glomeruli. In their descent through the outer medulla toward the inner medulla, the thin descending limbs (TDLs) of long loops of Henle are consistently excluded from the vascular bundles and occupy the interbundle region. The outer medullary segment of long TDLs (Type II epithelium) is elaborately developed with numerous cellular interdigitations. microvilli, and a cytoplasm well equipped with numerous organelles. The inner medullary segment of these long TDLs is characterized by yet another epithelium that is markedly reduced from its Type II predecessor and is designated as Type III epithelium. It is a very low, flattened epithelium with few cytoplasmic details. In a cross section of the inner medullary TDL, the Type III epithelium appears poorly interdigitated, with only two to four cell processes and their junctional complexes. Shortly before the bend of a long loop of Henle, the epithelium is again altered to one that is well-interdigitated and better equipped with cytoplasmic organelles (Type IV epithelium). It persists through the actual bend of the loop and throughout the entire thin ascending limb (TAL), until the latter's transition to the distal tubule at the level of the inner/outer medullary border. We conclude that the Type II epithelium of the outer medullary segments of long TDLs in Psammomys is suitably constructed for involvement in energized transport of solutes. The possibility for a similar role in the Type IV epithelium of the bends and TALs is not excluded by our data. However, the Type III epithelium of the inner medullary segments of long TDLs is most suitably constructed for the concentration of its luminal fluids via water extraction. A comparison between these epithelial types and their permeabilities in various species is presented.
The literature on the role of the kidney and renal morphological modifications in places of limited water supply is reviewed. The anatomical structures for urine concentration found in animals living in desert or arid environments, although not all occurring in one particular animal, are wide medullae, long loops of Henle, long proximal tubules, long collecting tubules, small renal corpuscles, extension of the renal pelvis, well developed elongated papillae, occurrence of giant vascular bundles, specialized ultrastructure of Henle's loops, epithelial changes in the collecting tubule, zonation of the vasa recta and peculiarity of the arterial supply to the kidney. The renal renin content is moderately high in these species. The renin-angiotensin-aldosterone system is very active, retaining Na+ with water. The urine is concentrated at the expense of other electrolytes. Both the renal blood and urinary flow rates are lower than in species with access to unlimited water supply. The juxtaglomerular apparatus components are topographically intimate for effective tubuloglomerular autoregulation of renal blood flow.
The venous drainage of the kidney of the one-humped camel (Camelus dromedarius) was studied in 17 kidneys of male and female adult animals. Injection of latex, plastoid as well as radiopaque substance (40% barium sulfate) were used to follow the distribution of the renal vein through the kidney tissue. The renal vein of the camel is unique as it gives off vv. interlobares I which drain the ventral half of the kidney, in addition to large cranial and caudal stem vessels from which vv. interlobares I of the dorsal surface branch. The general pattern of distribution of the renal vein in the camel's kidney resembles, more or less, that of the other domestic animals.
Intrarenal veins, although known to have thin walls, are considered to be simple conducting vessels. Using light- and electron microscopy, the distribution and structure of named intrarenal veins was examined qualitatively and quantitatively in rat kidneys fixed by retrograde arterial perfusion. Although the venous system follows the pattern of arterial branching in general, a class of intracortical veins similar in appearance to interlobular veins but without a companion artery was found in the present study. It is suggested that these vessels be designated intralobular veins. Structurally, we have found intrarenal veins to be surprisingly similar to peritubular capillaries both in respect to their spatial relations to renal tubules as well as ultrastructurally. Like peritubular capillaries, the majority of the wall of intrarenal veins is intimately apposed to renal tubules. This fraction decreases centrally, values of 0.83 being obtained in intralobular veins, 0.69 in interlobular veins, and 0.56 in arcuate veins. The walls of intrarenal veins are comprised of little more than an endothelium, which, like peritubular capillaries, is remarkable for its thinness, high density of fenestrae, and lack of extraintimal elements. Endothelial thickness was not significantly greater in either interlobular or arcuate veins than in peritubular capillaries; the fenestrae were, however, about twice as frequent in peritubular capillaries as in interlobular or arcuate veins and 35 times more frequent than in interlobar veins. The size and numerical and volume densities of uncoated endocytotic vesicles did not differ significantly between peritubular capillaries and any of the intrarenal veins. Based on their marked qualitative and quantitative similarities to peritubular capillaries, we conclude that, like the latter, intrarenal veins are capable of sustaining passive transport between plasma and interstitium.
Brush border membranes (BBM) have been prepared from fresh samples of normal human kidney cortex and compared to that from mouse, rat, and rabbit. Human BBM presents a sodium dodecyl sulfate gel electrophoresis protein pattern similar to that of the animal species with 22 proteins having the same molecular weight (MW). Incubation with inorganic 32P reveals a phosphate-binding protein (MW 78,000) common to the animal species. However, the binding capacity is lower in man: 4.3 +/- 2.2 pmol Pi/mg protein compared to 9.9 +/- 2.1, 29.7 +/- 4.3, and 31.1 +/- 5.2 in rabbit, mouse, and rat, respectively. The MW of the binding protein corresponds to that of the monomer of alkaline phosphatase. Alkaline phosphatase activity follows the same increasing order in the four species. The Na gradient-dependent Pi uptake by human BBM vesicles is low: Vmax is 0.90 +/- 0.05 nmol/mg/20 s compared to 1.3 +/- 0.1, 1.5 +/- 0.2, and 5.2 +/- 0.2 in rabbit, mouse, and rat, respectively. However, the Km values are within the same range for the four species.
Primary discuss on thirsty-resistant of camels
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Anatomy and Histology and Embryology of Livestock and Poultry
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