The document summarizes the anatomy and histology of the excretory system in fish. It describes the key parts of the system - the kidneys, ureters and urinary bladder. It discusses the structure and functions of the different regions of the kidney, including the head kidney which is hematopoietic and endocrine, and the trunk kidney which is excretory. It also describes the histology of the nephrons, ureters, and other tissues like the corpuscles of Stannius. Overall, the document provides a detailed overview of the excretory system and kidney structure-function relationships in fish.
In aquatic animals such as fish respiration takes place through special respiratory organs called gills, however lung fish respiration takes place through lungs. Gills are present on both the sides of the head of fish. The gills are covered by gill covers also called operculum. When the fish open its mouth, water is drawn into the buccal cavity and passed through the gills. The gills contain special type of cells that absorb the oxygen present in water. The absorbed oxygen is then supplied to all the cells of body through blood. In the cells, oxygen is converted into carbon dioxide and returned back to gills through blood. Ultimately, the gills release the carbon dioxide in water passing through them.
Respiration in Fish
The gills of fish are very efficient; it is estimated gills can extract about 80% oxygen dissolved in water. In addition to the respiratory organs, the gills have an important role in maintaining the right balance of salts in the body.
Fertilized fish eggs are known as Fish seeds. In simple words, they are the baby fishes used for seeding new Ponds in fisheries. Fish seed transportation is a process by which transfer of fish seed from the hatchery or place of collection to the rearing ponds.
In aquatic animals such as fish respiration takes place through special respiratory organs called gills, however lung fish respiration takes place through lungs. Gills are present on both the sides of the head of fish. The gills are covered by gill covers also called operculum. When the fish open its mouth, water is drawn into the buccal cavity and passed through the gills. The gills contain special type of cells that absorb the oxygen present in water. The absorbed oxygen is then supplied to all the cells of body through blood. In the cells, oxygen is converted into carbon dioxide and returned back to gills through blood. Ultimately, the gills release the carbon dioxide in water passing through them.
Respiration in Fish
The gills of fish are very efficient; it is estimated gills can extract about 80% oxygen dissolved in water. In addition to the respiratory organs, the gills have an important role in maintaining the right balance of salts in the body.
Fertilized fish eggs are known as Fish seeds. In simple words, they are the baby fishes used for seeding new Ponds in fisheries. Fish seed transportation is a process by which transfer of fish seed from the hatchery or place of collection to the rearing ponds.
Exotic fish introduction to india and their impact on indigenous speciesAshish sahu
The exotic varieties of fish have been found to encroach the natural water bodies and adversely affect the indigenous fish species. ... Owing to extensive practice of composite culture, three fast growing exotic fishes are introduced along with the three Indian major carps.
what is Fish blood.reading this you will know about fish blood.a short description about fish blood
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Origin of the Lateral Line System
Lateral line is a canal along the side of a fish containing pores that open into tubes supplied with sense organs sensitive to low vibrations.
Robert H. Denison explained the origin of the lateral line system. He explained that early vertebrates had a pore-canal system in the dermis which functioned as a primitive sensory system in detecting water movement.
Through the evidences from fossils, embryology and comparative anatomy, Denison (1966) established that the inner ear is closely related to the lateral line system. He found a distinct relationship between the pore canal system and the lateral line in Osteotraci.
The inner ear and the lateral line are developed from ectodermal thickenings, called dorso-lateral placodes. These have a number of similarities, including receptors with sensory hairs, and are both innervated by fibers in the acoustico-lateral area of the brain.
The pore canal system is present and developed in Osteostraci (ostracoderm).
It is also present in Heterostraci which is another group of ostracoderms and includes early vertebrates such as lungfishes and crossopterygians.
As its presence is extensive, it is reasonable to suggest that the pore canal system was a primitive character in early vertebrates .
In transverse sections also , it is very difficult to differentiate the pore canal system from a lateral line canal.
Structure of the Lateral Line System
Epidermal structures called neuromasts form the peripheral area of the lateral line.
Neuromasts consist of two types of cells, hair cells and supporting cells.
Hair cells have an epidermal origin and each hair cell has one high kynocyle (5-10 μm) and 30 to 150 short stereocilia (2-3 μm).
The number of hair cells in each neuromast depends on its size, and they can range from dozens to thousands.
Hair cells can be oriented in two opposite directions with each hair cell surrounded by supporting cells.
At the basal part of each hair cell, there are synaptic contacts with afferent and efferent nerve fibers. Afferent fibers, transmit signals to the neural centres of the lateral line and expand at the neuromast base. The regulation of hair cells is achieved by the action of efferent fibers.
Stereocilia and kinocilium of hair cells are immersed into a cupula and are located above the surface of the sensory epithelium.
The cupula is created by a gel-like media, which is secreted by non-receptor cells of the neuromast.
Central nervous system: The central nervous system consists of the brain and spinal cord. The brain plays a central role in the control of most bodily functions, including awareness, movements, sensations, thoughts, speech, and memory. Some reflex movements can occur via spinal cord pathways without the participation of brain structures. The spinal cord is connected to a section of the brain called the brainstem and runs through the spinal canal.
Peripheral Nervous System: Nerve fibers that exit the brainstem and spinal cord become part of the peripheral nervous system. Cranial nerves exit the brainstem and function as peripheral nervous system mediators of many functions, including eye movements, facial strength and sensation, hearing, and taste.
The autonomic nervous system: The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. This system is the primary mechanism in control of the fight-or-flight response.
The autonomic nervous system comprises two antagonistic sets of nerves, the sympathetic and parasympathetic nervous systems. The hypothalamus is the key brain site for central control of the autonomic nervous system, and the paraventricular nucleus is the key hypothalamic site for this control.
Divisions of Nervous System:
The vertebrate nervous system has three divisions:
(i) A central nervous system comprising the brain and spinal cord. Its function is to receive the stimulus from the receptors and transmit its response to the effectors. Thus, it coordinates all the functions of the body.
(ii) A peripheral nervous system consisting of cranial and spinal nerves arising from the brain and spinal cord respectively. It forms a connecting link between the receptors, central nervous system (CNS) and effectors.
(iii) An autonomic nervous system made of two ganglionated sympathetic nerves, ganglia in the head and viscera, and their connecting nerves. The autonomic nervous system is often regarded as a part of the peripheral nervous system because the two are connected. But all the three divisions of the nervous system are connected intimately both structurally and functionally.
Fishes, amphibians, reptiles, and birds have paired pharyngeal ultimobranchial glands that secrete the hypocalcemic hormone calcitonin. The corpuscles of Stannius, unique glandular islets found only in the kidneys of bony fishes, secrete a peptide called hypocalcin.
Induced breeding is a technique where organism is stimulated by particular hormone or other synthetic hormone or by providing condition, introduced to breed in captive condition.
he kidneys are a vital organ critical to the human body. From filtering waste from blood to produce red blood cells, it serves a crucial role. With cells and tissue that work together in synchronized form for common function
Exotic fish introduction to india and their impact on indigenous speciesAshish sahu
The exotic varieties of fish have been found to encroach the natural water bodies and adversely affect the indigenous fish species. ... Owing to extensive practice of composite culture, three fast growing exotic fishes are introduced along with the three Indian major carps.
what is Fish blood.reading this you will know about fish blood.a short description about fish blood
source:<a>bd tips tech</a> the best bangla tech site http://www.bdtipstech.com
Origin of the Lateral Line System
Lateral line is a canal along the side of a fish containing pores that open into tubes supplied with sense organs sensitive to low vibrations.
Robert H. Denison explained the origin of the lateral line system. He explained that early vertebrates had a pore-canal system in the dermis which functioned as a primitive sensory system in detecting water movement.
Through the evidences from fossils, embryology and comparative anatomy, Denison (1966) established that the inner ear is closely related to the lateral line system. He found a distinct relationship between the pore canal system and the lateral line in Osteotraci.
The inner ear and the lateral line are developed from ectodermal thickenings, called dorso-lateral placodes. These have a number of similarities, including receptors with sensory hairs, and are both innervated by fibers in the acoustico-lateral area of the brain.
The pore canal system is present and developed in Osteostraci (ostracoderm).
It is also present in Heterostraci which is another group of ostracoderms and includes early vertebrates such as lungfishes and crossopterygians.
As its presence is extensive, it is reasonable to suggest that the pore canal system was a primitive character in early vertebrates .
In transverse sections also , it is very difficult to differentiate the pore canal system from a lateral line canal.
Structure of the Lateral Line System
Epidermal structures called neuromasts form the peripheral area of the lateral line.
Neuromasts consist of two types of cells, hair cells and supporting cells.
Hair cells have an epidermal origin and each hair cell has one high kynocyle (5-10 μm) and 30 to 150 short stereocilia (2-3 μm).
The number of hair cells in each neuromast depends on its size, and they can range from dozens to thousands.
Hair cells can be oriented in two opposite directions with each hair cell surrounded by supporting cells.
At the basal part of each hair cell, there are synaptic contacts with afferent and efferent nerve fibers. Afferent fibers, transmit signals to the neural centres of the lateral line and expand at the neuromast base. The regulation of hair cells is achieved by the action of efferent fibers.
Stereocilia and kinocilium of hair cells are immersed into a cupula and are located above the surface of the sensory epithelium.
The cupula is created by a gel-like media, which is secreted by non-receptor cells of the neuromast.
Central nervous system: The central nervous system consists of the brain and spinal cord. The brain plays a central role in the control of most bodily functions, including awareness, movements, sensations, thoughts, speech, and memory. Some reflex movements can occur via spinal cord pathways without the participation of brain structures. The spinal cord is connected to a section of the brain called the brainstem and runs through the spinal canal.
Peripheral Nervous System: Nerve fibers that exit the brainstem and spinal cord become part of the peripheral nervous system. Cranial nerves exit the brainstem and function as peripheral nervous system mediators of many functions, including eye movements, facial strength and sensation, hearing, and taste.
The autonomic nervous system: The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. This system is the primary mechanism in control of the fight-or-flight response.
The autonomic nervous system comprises two antagonistic sets of nerves, the sympathetic and parasympathetic nervous systems. The hypothalamus is the key brain site for central control of the autonomic nervous system, and the paraventricular nucleus is the key hypothalamic site for this control.
Divisions of Nervous System:
The vertebrate nervous system has three divisions:
(i) A central nervous system comprising the brain and spinal cord. Its function is to receive the stimulus from the receptors and transmit its response to the effectors. Thus, it coordinates all the functions of the body.
(ii) A peripheral nervous system consisting of cranial and spinal nerves arising from the brain and spinal cord respectively. It forms a connecting link between the receptors, central nervous system (CNS) and effectors.
(iii) An autonomic nervous system made of two ganglionated sympathetic nerves, ganglia in the head and viscera, and their connecting nerves. The autonomic nervous system is often regarded as a part of the peripheral nervous system because the two are connected. But all the three divisions of the nervous system are connected intimately both structurally and functionally.
Fishes, amphibians, reptiles, and birds have paired pharyngeal ultimobranchial glands that secrete the hypocalcemic hormone calcitonin. The corpuscles of Stannius, unique glandular islets found only in the kidneys of bony fishes, secrete a peptide called hypocalcin.
Induced breeding is a technique where organism is stimulated by particular hormone or other synthetic hormone or by providing condition, introduced to breed in captive condition.
he kidneys are a vital organ critical to the human body. From filtering waste from blood to produce red blood cells, it serves a crucial role. With cells and tissue that work together in synchronized form for common function
excretion in unio and pila_poojasoni_new.pptxPooja Soni
The Bojanus organ and Keber’s organ are both part of the excretory system of Unio which belongs to the phylum Mollusca.
The organs of Bojanus or Bojanus organs are excretory glands that serve the function of kidneys in some of the molluscs. In other words, these are metanephridia that are found in some molluscs.
Keber's organ is a gland-like structure responsible for the removal of the nitrogenous wastes. It is also known as 'pericardial gland' and is a large, reddish-brown glandular mass.
Tissue-system grade
Triploblastic
Coelomate
Unsegmented
Bilaterally symmetrical
Body divisible into head,mantle,foot and visceral mass
Digestive system complete
Circulatory system closed type
Respiration direct by gills or lungs or both
Excretion by paired metanephridia
Terrestrial or aquatic
In Pila globosa, the excretory organ is a large kidney or renal organ or organ of Bojanus.
Like the gill, it is the organ of the left side, that of the right side having disappeared or modified into the gonoduct.
It communicates with the exterior on one hand and with the pericardial cavity representing coelom on the other; it is, thus, of the nature of a coelomoduct.
It consists of two chambers, a right anterior and a left situat posterior.
Anterior renal chamber :
It is more or less an oval organ, reddish in colour and lies anterior to the pericardium.
It opens into the branchial chamber of the mantle cavity through a slit- like opening near the epitaenia.
At the other end, it communicates with the posterior renal chamber through an internal opening.
Internal cavity of the anterior chamber is very much reduced due to the presence of many triangular leaf like processes or lamellae, those arising from the roof alternating with those from the floor.
Dorsal surface of the chamber is marked by numerous transverse grooves, corresponding to these internal lamellae.
Lamellae on the roof are arranged on either side of a median longitudinal axis, or the efferent renal sinus.
Lamellae on the floor are arranged on either side of a similar median axis, the afferent renal sinus, which is the right branch of the peri-intestinal sinus.
It breaks up into the numerous branches to supply the lamellae on both the sides.
Posterior renal chamber :
It is a broad, brownish to grey and hook-shaped chamber, situated behind the anterior renal chamber, in between the rectum on the right and the pericardium and the digestive gland on the left.
The ventral glandular portion of the kidney extracts guanin and other nitrogenous waste products of metabolism from the coelomic pericardial fluid as well as the blood supplied to the kidneys.
The walls of the pericardial sinus are also glandular, and supposed to secrete waste materials from the blood into the coelomic cavity.
The ciliated epithelial lining of the bladder produces an outgoing current, thus conveying excretory fluid from the glandular part of the kidney to the suprabranchial chamber which leads to the excurrent siphon.
There is reabsorptio
The Cephalochordata are a small subphylum (about 28 species) of small, 5 to 10 centimetres long.
All known species are marine. They occur all around the world in both temperate and tropical waters.
Cephalochordates live in shallow marine or brackish water all over the world. They can actively swim around, but most of the time are sedentary, buried in sand.
Hope this will help you in studying! :) because you used this, you are obliged to do the same, to upload publicly so that others will have an easy way on researching for their school works! keep up the good work studes! Goodluck!
Anatomy of the urinary system
Anatomy of the kidneys
Anatomy of the nephron
Anatomy of the ureters
Anatomy of the urinary bladder
Anatomy of the urethra; male and female urethra
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1. AAH 504 SYSTEMATIC PATHOLOGY
EXCRETORY SYSTEM
ANATOMY AND HISTOLOGY
BY
R.PRATHISHA
2. kidney
• Often fused ,it lies in the retroperitonial location just
ventral to the vertebral column,and can extend from
the head region to the posterior abdomen as one
organ or it can have distinct head and trunk regions
3. • Light or dark brown or black organ normally
extending the length of the body cavity
• kidneys - A primary function of the kidney is
osmoregulation. In fresh water the kidney saves
ions and excretes water. In saltwater fish, the
kidney excretes ions and conserves water. The
majority of nitrogenous waste is excreted through
the gills.
Kidney:
Anterior / head kidney(HAEMATOPOITIC)
Posterior /excretory kidney
4. Excretory System in Fishes
• In vertebrates, the excretory and reproductive
organs are morphologically interrelated because
certain excretory ducts are used for the
discharging of gametes also. So it has been
convenient to treat them together as
urinogenital system.
• In fishes, the association is restricted to
the pseudo-copulatory papilla through which
both the excretory and generative products leave
by a common vent. The association is more
intimate in male than in female
5. The excretory organs consist of
• kidneys,
• ureters and
• urinary bladder.
The urinary bladder is not homologous to that
of higher vertebrates
6.
7.
8. Kidney:
• Kidneys of vertebrates are made up of nephron
or kidney tubules.
• In ancestral vertebrates, kidney possesses one
nephron for each of those body segments that lay
between the anterior and posterior end of the
coelom.
• The nephron drained into a duct called Wolffian
or archinephric duct located posterior to the
cloaca. This sort of kidney is known as
holonephros because it extends to the entire
length of the body.
9. • The holonephros is found today in the larvae
of certain cyclostomes but not in any adult.
10. • In fish and amphibians
the most anterior tubules
have been lost, some of
the middle tubules are
associated with tests and
there is a concentration
and multiplication of
tubules posteriorly
• Such a kidney is known as
a posterior kidney or
opisthonephros.
11.
12. • Generally in fishes, the tubules of the anterior
region become functional in early life and are
designated as pronephors
13. • And the tubules present in the posterior
regions take up excretory function throughout
life. This region of the functional tubules is
known as mesonephros
14.
15. • The kidneys occupy dorsal position in the
body cavity and is placed just ventral to the
vertebral column.
• In teleost, the kidney is distinguished into
head and trunk regions-clearly discernible in
carps
• Head kidney is non-excretory and endocrine in
function whereas trunk kidney (posterior
kidney) is excretory in nature.
16. The peculiarities are mentioned as
follows:
1. The head kidney is endocrine in nature. It has
inter-renal gland homologous to adrenal cortex
of mammals. It has chromaffin cells also which
are similar to the adrenal medulla of mammals.
2. In the kidneys are embedded yellow bodies
called corpuscle of Stannius. It is endocrine in
function.
3. Head kidney is the site for the development of
the blood.
17. 4. Both head and trunk kidneys contain
heterotopic thyroid follicles.
• On the basis of morphology and distinction
between head kidney and trunk kidney,
Ogawa (1961) classified marine teleost kidney
into five categories
18.
19. • In the first category there is no clear
demarcation between head and trunk kidneys
and the two kidneys are completely fused
throughout e.g., rainbow trout and salmon.
20.
21. • In the second type there is
clear macroscopic
demarcation between the
head and trunk kidneys. The
middle and posterior portions
are fused.
• From the middle fused part
are given out two tube like
structures anteriorly, which
are separate from each other
and at the tip of these tubes
are present sac-like structure,
the head kidneys, e.g., Ayo,
Cyprinidae and carps
22.
23. • In the third type, there is also a clear distinction
between the head and trunk kidneys.
• The kidney is distinguished into head, trunk and
tail portions. The tail kidneys are fused, while
the trunk and head kidneys are separated and are
located at the tip of the anterior most region. The
head kidney, is generally globular in shape, e.g.,
Notopterus notopterus
24.
25. • In the fourth type there is no morphological
demarcation between head and trunk
kidneys. The two kidneys are separate except
at the posterior most region where the
kidneys are fused
26. Serial sections of eel kidney. (A) Periodic acid–
Schiff (PAS) staining. (B) Immunohistochemical
staining with β-actin antisera. (C) Schematic
drawing of eel nephron showing localization of
the P1 and P2 segments. White and black
arrowheads show the P1 and P2 segments,
respectively, of the eel proximal tubule, and
white arrows show the distal tubule (Dt).
Scale bar, 20 μm.
27. • In the fifth type, the two
kidneys are completely
separate from each other.
The tail kidneys are thin
tube-like while the
anterior trunk kidneys are
thick. There is no
morphological distinction
between head and trunk
kidneys.
28. Kidneys of Some Indian Fishes:
• The kidneys of Clarias
batrachus are situated in
the abdominal cavity.
• The head kidney are in the
form of two triangular
lobes Channa marulius,
Channa punctatus and
Channa gachua
• The anterolateral side of
the trunk kidneys on either
side is provided with
rounded structures and
are known as mesonephric
lobes
29. • The two kidneys are fused in the
middle, forming a flattened wing-like
middle portion of the trunk kidneys.
From this wing-like structure, two
tube-like structures are given out
anteriorly which are separate from
each other. At the anterior end of
these tubes are present sac-like
structures known as head kidneys
• The two head kidneys are separate.
Posteriorly, from the middle part of
the trunk kidney, the kidneys become
narrow. This part is called as tail
kidneys. Externally, a depression is
visible which indicates that they are
two structures.
• The tail kidneys are also fused.
30.
31. Ureter:
• The mesonephric ducts or ureters lie closed together in
the median line. Anteriorly, they are separate,
posteriorly the two mesonephric ducts open separately
into urinary bladder.
• In some species a sac-like enlargement is clearly
visible in the posterior region of the ureter known as
urinary bladder, but it is not homologous to that of
higher vertebrates.
• The urinary bladder usually opens to the exterior by a
common urinogenital aperture in the’ male fish but a
separate urinary aperture is present in female fish as
found in Mystus
32.
33.
34. Histology of Trunk Kidney
The trunk kidney or body kidney,
• The number of renal tubules varies in different
fishes.
• The functional unit of kidney is nephron.
interstitial
lymphoid
tissue
Renal
tubules
(nephron
s)
35. • Each nephron consists of two parts,
• The renal corpuscle or Bowman’s capsule is
double layer cup-like structure of uriniferous
tubule which contains tuft of capillaries
known as glomerulus
The renal corpuscles/
Bowman’s capsule
(Malpighian body)
The renal tubule
(urinary tubule)
36. Segment of urinary tubule
(renal tubule) ;
• proximal convoluted
segment (which further
divides into segment I
and segment II),
• the intermediate and
• distal segments
37. • The distal segment is absent in marine fishes
• The segment of Henle found in higher
vertebrates is also absent in the fishes
• The glomerulus + Bowman’s capsule=Renal or
Malpighian capsule. It is a filtration apparatus
of kidney.
38.
39. • The renal corpuscle contains an additional group
of cells known as mesangial cells.
• Mesangial cells are also present in the space
between the loops of glomerular capillaries. They
are most obviously present at the vascular stalk.
• The function of mesangial cells are not known,
although experimental data show that they can
remove large proteins from the glomerular basal
lamina
40. • Oguri (1982) reported the presence of
juxtaglomerular cells in the wall of afferent
arterioles. These cells contain secretory granules
and are specialized muscular cells.
• They are the source of the hormone renin.
• Renin is the hormone active in increasing blood
pressure.
• In mammals, the juxtaglomerular apparatus is
thought to provide feedback information for the
control of glomerular filtration.
41. • The intermediate segment is well-developed
in carp kidney but absent in several species of
fishes.
• The distal convoluted segment could be
distinguished because of coarse granules in
the cytoplasm.
• The distal convoluted segments are absent in
the kidney of marine fishes
42. Ureter:
• The function of the ureter is to conduct urine
up to urinary bladder.
• Histologically, it is made up externally by
tunica adventitia, the middle layer contains
lamina propria and smooth muscles and
outermost layer is columnar epithelial cells.
43. • The ureters or archinephric ducts, which
conduct urine from the collecting ducts to the
urinary papilla, may fuse at any level and may
be dilated, after fusion, to form a bladder
• The urinary ducts open to the outside
posterior to the anus.
44. Urinary bladder
• Urinary bladder is a thin walled saclike
structure
• It is also made up of three layers similar to the
ureter
45. Head Kidney
• Embryo logically the head kidney originates from
pronephros
• The inter-renal gland and chromaffin cells are present in
the head kidney.
Inter-renal gland:
• In Xenentodon cancila, the inter-renal body lies as a
compact mass surrounded by a capsule of connective
tissue.It lies at a short distance behind the septum
transversum and is an elongated mass about twice the size
of a wheat grain.
• The cells are basophilic with large nuclei.
• The inter-renal gland of fish is homologous to the adrenal
cortex of mammals.
46. • In eel (Anguilla japonica) the gland is located in
the wall of the post-cardinal vein running closely
along the head kidneys
Chromaffin tissues:
• Chromaffin tissues are also present, this tissue is
homologous to adrenal medulla of mammals.
• Both inter-renal and chromaffin tissues are
present in many fishes either discrete structure
or intermingled in the tissue
47. FUNCTIONS:
• The histochemical examination of teleostean
inter-renal cells shows 3-B hydroxysteroid dehy-
drogenase and glucose 6 phosphate
dehydrogenase.
• These are important in biosynthesis of steroid
hormones.
• chromaffin cells secrete- adrenalin and
noradrenalin whereas
• inter- renal secretes - corticosteroid
48. Urine
The freshwater teleosts
• To excrete large amount of water which is taken
through mouth.
• Urine contains;
- Creatine, unidentified nitrogenous compounds some
of which are amino-acids, little amount of urea and
ammonia.
- The urine is copious and have very low in
concentration of electrolyte.
- Nitrogen amounting to 2 to 25% of total nitrogen
excreted by freshwater fishes.
49. Marine fishes produce;
• scanty urine, which contain Ca++, Mg++, SO4
– –,
SO4
– – and PO4
– –.
• TMAO (i.e., tri-methylamine oxide) are also
excreted out.
• Ammonia, urea and monovalent electrolytes
(Na+, Cl–), however, are excreted mainly
through gills.
50. Corpuscles of Stannius
• The corpuscles of Stannius is a small ductless
gland (endocrine gland) situated partly or
completely embedded in the kidney on its
dorsal, dorsolateral and ventrolateral side
• corpuscles of Stannius work in conjuncture
with pituitary gland, which produces a distinct
hypercalcemic effect, to maintain a relatively
constant level of calcium in Fundulus
heteroclitus
51. • The corpuscles of
Stannius is situated
near the middle portion
of mesonephros in
salmnoid fishes
• but in majority of fishes
they are located in the
posterior region of the
kidney
52. Heterotopic Thyroid Follicle
• The thyroid in fishes is
not a discrete organ but
fused in the kidney also,
hence it is known as
heterotopic.
• The thyroid follicles are
scattered in the
haemopoietic tissue of
the head, mesonephric
lobe (air breathing fishes)
and in trunk kidneys
53. Innervation
• The kidneys are richly innervated by
autonomic nervous system. The nerves
generally penetrate in the kidney through
blood vessels. They divide and re-divide to
form nerve plexuses
54. Hormones and Enzymes
• Renin is the hormone secreted from
juxtaglomerular cells. The hormone is active in
increasing blood pressure and controls the
glomerular filtrate. The cholinergic nerve
endings secrete an enzyme acetyl
cholinesterase (AChE)
• The lower Km in head kidneys indicates higher
enzyme activity
55. Blood Supply of Kidney:
• The kidney of fish receives blood supply by the
renal artery and renal portal vein.
• The renal artery supplies blood to glomeruli,
where high blood pressure helps to separate
glomerular filtrate.
• The renal portal veins are connected to
capillary network around the kidney.
56. • Arterial blood is supplied to the
kidney(glomerulus) by renal arteries arising
directly from the aorta or from segmental vessels
• The efferent arterioles then supply blood to
peritubular capillaries
• In marine and euryhaline species the Peritubular
capillaries also receive blood from caudal or
segmented vessels, draining the tail region and
constituting a renal portal system. This portal
blood is thus venous
57. Endocrine elements
• Thyroid follicles
• Corpuscles of stannius
• Chromaffin cells
• Interenal tissue
Interenal tissue:
Located around major blood vessels which
represent the mammalian adrenal medula and
cortex respectively
58.
59.
60. Histological anatomy
• Histological anatomy is wonderful example of
how structure is driven by functional needs
• Extcretory function fullfilled by gills the
function of fish nephron is mainly
osmoregulation
61. Nephron
Fresh water Marine Euryhaline
Larger nephron well -
vascularised glomerulus
marine nephron is typically
smaller in size and
consists of a glomerulus
nephron combining
the structure of both types,
Two distinctive proximal
segments, a narrow
ciliated intermediate
segment, a distal segment
and a collecting
duct system.
a neck segment, two or
three proximal segments,
which constitute the major
component and the
collecting
duct system.
being similar to that of the
marine teleost with, in
addition, a distal segment
similar to that of the fresh -
water teleost.
62. Dogfish excretory kidney. The paired
elongated kidneys are located
retroperitoneally near the vertebralcolumn.
The anterior ribbon-like parts are separated
whereas caudal parts form a single mass. The
elasmobranch
kidney is remarkable for its unique structure
and is divided in two main histological zones :
the sinus zone and the bundle zone.
This low magnification presents a section
through the sinus zone displaying numerous
individual crosssectioned tubules. The later are
of two types : large(proximal) and thin (late
distal) tubules. Large venous sinuses (* - a
filled one and an empty one) are evident
among the tubules. Steroidogenic tissue of the
interrenal tissue (1) and chromaffin tissue (2)
are clearly visible .Collagen is stained in blue.
63. Anguilla anguilla
Chloride cells. Osmoregulation in teleosts is an
integrated combination of transport activity by
the kidney, the gut and the gills. The chloride
cells of the gills are implicated in active Cl-
transport. This photomicrograph
shows two chloride cells (arrows) located
within the thick epithelium of a primary
lamella (gill fillament). The granular
appearance and the eosinophilia
of the cells are due to the abundance of
mitochondria which are in close relation with
the basolateral infoldings of the plasma
membrane. Arrowhead shows the proximal
part of a secondary lamella.Chloride cells are
sometimes present at the beginning of the
digestive tract
64. Transverse section of the distal portion of the rectal
gland. The rectal gland is a slender, blind-ended, fi
nger- like appendix present in all elasmobranchs. This
epithelial gland leads to the post-valvular intestine
(rectum) via a large excretory duct. It is an organ of
osmoregulation producing a fluid essentially consis-
ng of a sea water-hyperosmotic NaCl solution. The
rectal gland is suspended in the abdominal cavity by
a mesentery. The arterial supply is the rectal gland
artery (white arrow).
The rectal gland is a compound tubular gland
composed of a peripheral capsular wall (1 – collagen
ingreen), a glandular parenchyma (2) and a duct
portion. The glandular portion is mainly composed of
secretory tubules radially oriented to drain into the
central region where the large collecting duct (not
visible in this section) is lined by a stratfied
epithelium.The lower end of the epigonal organ (3)
is attached to the rectal gland
65. Glandular parenchyma of rectal salt gland.
The micrograph presents secretory tubules
whose lumens are clearly lined with a simple
cuboidal epithelium.
Bouin-fixed sections usually give little
information on cytological specializations
associated with active electrolyte transport.
However one can see striations
(thin arrows) in the cytoplasm of the
epithelial secretory cells. The appearance of
striations noted with the light microscope, is
found in electron micrographs to be due to the
vertical alignment of long and numerous
mitochondria closely related to deep invagina
ons of the basolateral plasma membranes.
Numerous blood capillaries (arrows) run
between the tubules.
66. Scyliorhinus canicula (MT / HM)
Glandular parenchyma of rectal salt gland.
Delicate strands of fibroelastic tissue (collagen
in blue) coming from the capsule invade the
glandular portion and surround the secretory
tubules (1).
The rectal gland has a rich blood supply from
the rectal gland artery which breaks up into
numerous arterioles in the capsular wall. The
arterioles then penetrate into the glandular
parenchyma as a system of blood sinusoids (2)
from which secretory cells can remove
relatively large amounts of NaCl. Capillaries
finally coalesce as the rectal vein that emerges
from the gland, becoming the dorsal intestinal
vein.In the secretory tubules the fluid flows in
the opposite direction to that of the blood in
the capillaries thus constituting a
countercurrent exchange.
67. Scyliorhinus canicula Rectal salt gland. At the
centre a cross-sectioned secretory tubule.
In secretory tubules two cell types occur : the
predominating secretory cells (black arrows)
and scattered goblet mucous cells mainly
visible in the proximal part of the gland near
the rectum.These cells are a model for the
transport of chloride : Cl- enters the cell across
the basolateral cell membrane via a
cotransporter and leaves the cell across the
luminal membrane via a CFTR-like channel.
Note collagen in blue and some capillaries
(short arrows).1
68. • In general fish glomerulai are structurally
similar to mammalian glomerulai
fish kidney
Renal corpuscle juxtaglomerular cells in
bowmans capsule afferent arterioles
70. Glomerulus from the midkidney of
common carp. PAS ×600. (By courtesy
of Dr M.
Yokote.)
71. Kidney of carp:This section
shows two large rounded renal
corpuscle (long arrows).The
glomeruli (*) ,(erythrocytes in
orange) and the hematopoietic
areas (•).
72. Renal tubule:
begins with a short neck portion characterized
by low cuboidal epithelium with long cilia
Urine
proximal convoluted tubule(distal
convoluted tubule)
segment 1
segment 2
73. characteristics Segment 1 Segment 2
Epithelial cells Eosinophilic cuboidal to
columnar epithelium
Columnar & taller than
seg 1
Brush border Distinct in tubular
lumen
Prominent but lacks
tubular system
Nuclei Large ,round may be
central or basal
Oval(acidophilic),
centrally located
cytoplasm Have extensive tubular
system, lysosomes
&vesicles
*Intermediate segment
74. Kidney. Two transverse sections (1) and
one longitudinal section (2) of proximal
convoluted tubules are illustrated. These
tubules are easily identfied by the dark-
stained brush borders (arrowheads). The
brush border enhances reabsorption of fl
uid and solutes from the lumen through
or between the cuboidal epithelial cells
and into capillaries. In addition, a distal
tubule in transverse section is also
noticed (3).The rest of the micrograph is
filled with hematopoietic tissue.
75. Transverse section of a distal
convoluted tubule.These
tubules can usually be
distnguished from proximal
ones by the absence of a
brush border and therefore by
a more defined lumen. These
tubules lead to the collecting
tubules which merge to form
collecting ducts. The distal
tubule is lacking most of the
marine teleosts.
76. Transverse section of a proximal
convoluted tubule.
proximal tubule is the constant
presence of microvilli constituting
the brush border
(arrow).Erythrocytes stained orange.
77. Oncorhynchus mykiss
General view of kidney
parenchyma. The brush borders
of the proximal tubules are
heavily stained (1) whereas the
distal segments (2) are unreacti
ve. 3 : points to renal corpuscles,
slightly
reactive. 4 : hematopoietic
tissue.
78. Kidney of trout: Lectin reactive
signal was detected on the brush
border (1) of the proximal
tubules but not in the distal
tubules (2) which lack a brush
border. Melanomacrophage
centers (black)
and hematopoietic tissue (3) can
be seen.
80. Transverse section through the posterior
abdominal cavity of a xipho. The
photomicrograph shows the
(two) ureters (arrows), large ducts conducting
urine from the kidneys. In some fish they fuse
to form a common duct opening directly
outside whereas in others they distend in a
urinary bladder. Each ureter duct is lined with a
tall columnar epithelium. The notochord (*)
surrounded by vertebral bone (mint
green) occupies the upper part of the picture.
81. Pangio kuhlii
Cross section of posterior kidney. As
Cyprinidae,Cobitidae have partially fused
kidneys in their posteriorvparts. Kidneys
appear at this level as a single mass (*)
essentially composed of renal tubules.Ureters
(short arrows) are ventrally located and
arranged side by side
proximal as well as distal tubules are
unstained.One can also see the caudal
vein (1) in the centre of renal ssue, some
dark previtellogenic oocytes(2 - see
chapter 14) and abdominal musculature
(3).Long arrow points to the dorsal
aorta.
82. Enlarged portion of distal ureter
urinary bladder
Thin walled sac
Distinct histological layers similar to ureter
ie.,1/2 layers of cuboidal to columnar
epithelium lining tunica media and tunica
adventitia
83. Poecilia reticulata
Urinary bladder. Longitudinal section of one of
the ureters (black arrow) running into the
urinary bladder(*). In many bony fi shes,
enlargement of the urinary ducts serve as
bladder. An empty bladder exhibits mucosal
folds (arrowheads) that disappear
when the bladder is distended (filled with
urine). The wall of this hollow sac contains
dense smooth muscle bundles (yellow
arrows). Note near these structures the
presence of skeletal muscle fibers (red - x) of
the gonopod musculature. At the lower left
corner a portion of male gonad (dark) is
visible.
84. Trisopterus luscus
Kidney of pouting. glomeruli are small (long
arrows).The short arrows indicate some
proximal tubules. In addition,
melanomacrophage centers (brown black) are
also visible among hematopoietic cells (*)
Editor's Notes
These bodies are visible macroscopically in some fishes while in others they are intermingle in the kidney tissues.
Regarding freshwater teleost, Ogawa (1961) suggested that kidneys can be grouped into first three of the five types described above
which are separated from each other by a very narrow gap. They are not connected with the trunk kidney in Clarias batrachus. The triangular head kidneys is present inMesonephric lobes are also present in Heteropneustes fossilis.
The bulk is removed out through gills as ammonia.
the head kidney of Labeo is 1.11 x 10-3 M and Vmax is 0.222 A/mg proteins/30 minutes. While the Km of the middle portion of trurk and tail kidney is 3.33 x 10-3M and Vmax is 5.0 A/mg proteins/30 minutes.
