This document describes a study on the air-breathing dendritic organ of the sharp tooth catfish (Clarias gariepinus). The organ is located in the suprabranchial chamber above the gills. It has two main parts originating from the second and fourth gill arches. Histologically, it consists of elastic cartilage core, vascular connective tissue layer, and stratified epithelial covering containing mucous glands. Blood vessels penetrate the epithelium, dilating into respiratory papillae near the surface. Scanning electron microscopy showed the organ's surface has double rows of respiratory lamellae separated by interlamellar spaces studded with microvilli. The complex branching structure produces a large surface area for
The respiratory system allows for the intake and exchange of oxygen and carbon dioxide. It consists of specific organs like lungs and gills that vary between aquatic and terrestrial organisms. In fish, gills allow for respiration in water via filaments that absorb oxygen. Lungs and swim bladders provide buoyancy and gas exchange in some fish that breathe air. Over time, organisms evolved accessory organs and different ventilatory mechanisms to support respiration on land or in water.
the slides were prepared by makerere university students doing bachelors of science in fisheries and aquaculture on the origin of fish respiratory gills citing origin in skate fishes
Accssory respiratiory organs in fishesaadiihussain
Gills are primary respiratory organs in fishes, Extra branchial respiration is highly useful for survival when oxygen supplied by gills is not sufficient.
The document describes respiration in several organisms. It discusses:
1) Respiration in earthworms, which occurs through their moist skin via cutaneous respiration. Oxygen diffuses into their bloodstream and carbon dioxide diffuses out.
2) Respiration in spiders, which uses book lungs - pairs of sac-like structures containing many thin plates that increase surface area for gas exchange.
3) Respiration in bony fish like rohu, which uses gills - feathery structures in the gill slits that are highly vascular and divided into lamellae to efficiently uptake oxygen from water pumped over them by the operculum.
Air sacs are thin walled non-muscular,non-vascular,non-elastic and bladder like membrane connected to the lungs
Air sacs are only the inflated extensions of the mucous membrane of some blindly ending bronchioles
Some of them extended to bones
In pigeon there are nine major air sacs
One of them is unpaired and others are paired
Unpaired air sac is interclavicular
Paired sac include cervical,anterior thoracic,posterior thoracic and abdominal air sacs
Abdominal and posterior thoracic sacs get filled with fresh air during inspiration.so they are called inspiratory air sacs
Others get filled with fresh air during expiration
Specialities in Birds respiratory system: Air sacs, specialized parabronchi , Unidirectional flow
Benifits of air sacs, Benefit of 2 respiratory cycles
Bird-like respiratory systems in dinosaurs
Rate of breathings in birds
The respiratory system allows for the intake and exchange of oxygen and carbon dioxide. It consists of specific organs like lungs and gills that vary between aquatic and terrestrial organisms. In fish, gills allow for respiration in water via filaments that absorb oxygen. Lungs and swim bladders provide buoyancy and gas exchange in some fish that breathe air. Over time, organisms evolved accessory organs and different ventilatory mechanisms to support respiration on land or in water.
the slides were prepared by makerere university students doing bachelors of science in fisheries and aquaculture on the origin of fish respiratory gills citing origin in skate fishes
Accssory respiratiory organs in fishesaadiihussain
Gills are primary respiratory organs in fishes, Extra branchial respiration is highly useful for survival when oxygen supplied by gills is not sufficient.
The document describes respiration in several organisms. It discusses:
1) Respiration in earthworms, which occurs through their moist skin via cutaneous respiration. Oxygen diffuses into their bloodstream and carbon dioxide diffuses out.
2) Respiration in spiders, which uses book lungs - pairs of sac-like structures containing many thin plates that increase surface area for gas exchange.
3) Respiration in bony fish like rohu, which uses gills - feathery structures in the gill slits that are highly vascular and divided into lamellae to efficiently uptake oxygen from water pumped over them by the operculum.
Air sacs are thin walled non-muscular,non-vascular,non-elastic and bladder like membrane connected to the lungs
Air sacs are only the inflated extensions of the mucous membrane of some blindly ending bronchioles
Some of them extended to bones
In pigeon there are nine major air sacs
One of them is unpaired and others are paired
Unpaired air sac is interclavicular
Paired sac include cervical,anterior thoracic,posterior thoracic and abdominal air sacs
Abdominal and posterior thoracic sacs get filled with fresh air during inspiration.so they are called inspiratory air sacs
Others get filled with fresh air during expiration
Specialities in Birds respiratory system: Air sacs, specialized parabronchi , Unidirectional flow
Benifits of air sacs, Benefit of 2 respiratory cycles
Bird-like respiratory systems in dinosaurs
Rate of breathings in birds
The document summarizes the respiratory systems of various vertebrates. It describes how oxygen and carbon dioxide are exchanged through external respiration using organs like gills, lungs, and skin. It then discusses the specific respiratory adaptations of fish, sharks, amphibians, reptiles, birds, and mammals, focusing on features like gill slits, swim bladders, lungs, and air flow patterns through the trachea and lungs.
comparative anatomy of respiratory system of Reptiles, Birds and Mammals.UttamaTungkhang
This document compares and contrasts the respiratory systems of reptiles, birds, and mammals. It notes that all three use aerial respiration through lungs, but that some reptiles and birds undergo specialized adaptations related to their habitats. For example, crocodilians have a bony secondary palate for breathing underwater, while some lizards can increase stamina through buccal pumping. The document outlines key parts of the respiratory tract and how gas exchange occurs differently depending on the type of animal.
The document discusses the swim bladder, or air bladder, of fish. It is an internal gas-filled organ that contributes to a fish's ability to control buoyancy. There are two types - physostomous, which is directly connected to the digestive tract, and physoclistous, which is not connected. The basic structure includes a sac-like shape with two layers, an epidermis and endodermis. The swim bladder varies in shape and size between fish species and allows fish to rise and sink in water by increasing or decreasing the volume of gas inside without changing mass. Its key functions are to act as a hydrostatic organ, adjustable float, aid in respiration, produce sound, and maintain the fish's
The respiratory system of pigeons is highly developed to support flight. It includes a respiratory tract, lungs, and air sacs. The respiratory tract contains nostrils, nasal sacs, a larynx, trachea, and a syrinx vocal organ. The small lungs lack a diaphragm. Branched air sacs aid respiration and regulate body temperature. Respiration occurs via two cycles, with air drawn into posterior air sacs on the first breath and to anterior sacs on the second, providing double oxygenation of blood to support flight.
Chordates evolved in water with gill slits for respiration. Some moved to land using lungs and skin respiration. Reptiles used lungs and some used cloacal respiration. Birds evolved a unique lung system with air sacs. Mammals used refined lungs. Whales evolved from land mammals but returned to sea, keeping lungs for respiration but adapting for aquatic life.
The respiratory system of poultry includes nasal openings, nasal passages, trachea, bronchi, lungs, and air sacs. It differs from mammals in that poultry have complete tracheal rings, an organ of phonation at the trachea bifurcation rather than near the pharynx, fixed non-expanding lungs, and air sacs that extend into pneumatic bones. Respiration involves inspiration through bronchi and expiration through air sacs, facilitating gas exchange through the lungs. Thermoregulation occurs via radiation, conduction, convection, and evaporation from the respiratory tract.
The respiratory system obtains oxygen from the surroundings and conveys it to the body while removing carbon dioxide. It is linked to the circulatory system which transports oxygen using blood. In humans, breathing is driven by the diaphragm and intercostal muscles expanding the thorax, drawing air into the lungs which exchange gases via alveoli into the bloodstream. The lungs have branching airways ending in alveoli with a vast surface area for gas exchange.
The respiratory system of mammals is highly efficient for gas exchange. The lungs contain millions of alveoli that have a vast surface area due to their grape-like clustering. Air enters the lungs through the trachea and branches into smaller bronchioles before reaching the alveoli. Gas exchange occurs across the thin walls of the alveoli where oxygen passes into the blood and carbon dioxide passes out. The avian respiratory system is also very efficient, with unidirectional airflow through parabronchi and cross-current blood flow, allowing birds to respire at high altitudes.
The document summarizes the evolution of the respiratory system from early aquatic respiration through the skin to modern lung-based respiration in terrestrial animals. It describes how early aquatic animals used their skin and later gills for gas exchange, followed by the emergence of lungs for aerial respiration. It details the development of lungs across different vertebrate classes including mammals, birds, reptiles, amphibians and their associated structures like trachea. The document also discusses recent advances in respiratory physiology and diseases.
The document summarizes respiratory systems in animals. It describes how invertebrates like jellyfish respire through diffusion, while others use gills or tracheal tubes. Vertebrates either use gills for aquatic respiration with water flowing over them, or lungs for terrestrial animals. Lung structure varies between groups, with mammals having the most surface area for gas exchange. The human respiratory system uses the nose, mouth, lungs and alveoli to oxygenate blood and remove carbon dioxide.
Fish gills are highly folded organs located on the sides of the head that allow for efficient gas exchange. They have a network of capillaries and lamellae that divide the gill filaments, providing a large surface area for oxygen diffusion. The gills have a good blood flow and thin membranes that allow for countercurrent exchange, maximizing oxygen transfer from the water to the bloodstream.
The document summarizes the respiratory systems of various chordates. It describes how skin, gills, and lungs have evolved for respiration in different vertebrates. Skin respiration occurs mainly in amphibians like salamanders through their thin skin. Cartilaginous and bony fishes respire using gills consisting of pouches and slits. Lungs evolved from the swim bladder of early fish and are present in tetrapods, with variations in structure between amphibian, reptile, bird, and mammalian lungs.
Dr. P.B.Reddy provides an overview of the comparative anatomy of the vertebrate respiratory system. The document discusses why animals need to breathe and defines internal and external respiration. It then describes the key characteristics and functions of respiratory organs across different vertebrate groups, including fish, amphibians, reptiles and others. Specific structures are examined such as gills, lungs and the mechanisms of gas exchange that occur.
The respiratory system consists of organs and structures used for respiration. In mammals, respiration occurs through pulmonary ventilation via the nasal cavity, lungs, and diaphragm. The lungs exchange gases through alveoli and are protected by the rib cage. Horses and marine mammals have respiratory adaptations like nasal breathing and mechanisms to prevent water inhalation during dives.
The document discusses the respiratory system. It describes that the respiratory system brings oxygen into the body and removes carbon dioxide. It then describes the upper respiratory system, which includes the mucous membranes, mucous, cilia, pharynx, epiglottis, and larynx. The lower respiratory system is also described, including the trachea, bronchi, bronchial tree, bronchioles, alveoli, lungs, and diaphragm. The document also lists and defines several vocabulary terms related to respiration. Finally, it discusses the equine respiratory disease known as strangles, including its symptoms and methods for treatment and prevention.
Birds require large amount of oxygen due to their flight activity in accordance to which their respiratory system is comparatively more complex and developed.
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.
Comparative physiology of respiratory system of different speciesirfan khursheed
This document summarizes and compares the respiratory systems of different animal species. It discusses how mammals, reptiles, amphibians, birds, fish, and insects breathe. For mammals, the lungs are the main respiratory organ, using the diaphragm and rib muscles for breathing. Air enters the nose and travels through the epiglottis, trachea, bronchi, bronchioles, and alveoli where gas exchange occurs. Reptiles and amphibians also use lungs but some reptiles lack a diaphragm. Amphibians can pump air through buccal pumping. Birds have air sacs and force air through their lungs like bellows. Fish use gills to exchange gases.
Comparative Anatomy of Respiratory System of VertebratesRameshPandi4
The document discusses the comparative anatomy of the respiratory systems of various vertebrates. It describes how respiration occurs through the skin, gills, lungs, and gas bladders in different organisms. It explains key differences in respiratory structures between cartilaginous fishes, bony fishes, and jawless fishes. Mechanisms of gas exchange are covered for fishes, as well as respiratory organs and processes for amphibians, reptiles, birds, and mammals.
A Transmission Electron Microscopic Study of the Olfactory Epithelium in Hill...AI Publications
Olfaction is primarily produced by the stimulation of receptor cells on the olfactory organ's neuroepithelial surface, surrounded by olfactory nerve fibres. Numerous fish life processes, including migration, communication, feeding, schooling, defence, and reproduction, depend heavily on olfactory signals and cues. The olfactory and reproductory systems are interconnected structurally and functionally, and puberty-related alterations in the olfactory epithelium are documented. The olfactory epithelium, which covers a large portion of the surface of the olfactory rosette, a structure found within the olfactory chambers on the fish rostrum, is where the olfactory receptor cells are situated. Although ultra structural transmission electron microscopic studies of the olfactory organ and bulb are carried out by some investigators but very sparse information is available on hillstream fishes and that is why this work has been undertaken to detail the structure of olfactory system in G. mullya by electron microscopy. Microvillous olfactory receptor cells are placed compactly adjacent to the supporting cell showing a junction complex : the zonula-ocludens. Polygonal white cells are present in between the basal cells and supporting cells. Small polyhedral basal cells lie just above the basal lamina of olfactory epithelium. Basal cells may be working as stem cells for regeneration of lost or damaged non sensory and goblet cells.
This document describes a study on the vertical zonation and composition of meiofauna in Rearing Pond 2 of the Zamboanga State College of Marine Sciences and Technology. Meiofauna samples were collected from four stations at depths of 0-2cm, 2-4cm, 4-6cm, and 6-8cm below the sediment surface using a corer sampler. The samples were fixed with 5% formalin and sieved through 1mm and 250 micron meshes to extract the meiofauna. The goal of the study was to determine the meiofaunal composition and vertical distribution in the pond.
This document discusses a study that found molecular and morphological evidence suggesting that the flagellate Ancyromonas is closely related to the common ancestor of metazoans, fungi, and choanoflagellates. Analyses of 18S rRNA gene sequences from major eukaryotic lineages using maximum likelihood, minimum evolution, and maximum parsimony supported Ancyromonas forming its own lineage, called Ancyromonadida, that is more closely related to opisthokonts than its nearest protist relatives. However, low bootstrap support for deep nodes limits the ability of 18S rDNA to fully resolve this aspect of eukaryotic phylogeny.
The document summarizes the respiratory systems of various vertebrates. It describes how oxygen and carbon dioxide are exchanged through external respiration using organs like gills, lungs, and skin. It then discusses the specific respiratory adaptations of fish, sharks, amphibians, reptiles, birds, and mammals, focusing on features like gill slits, swim bladders, lungs, and air flow patterns through the trachea and lungs.
comparative anatomy of respiratory system of Reptiles, Birds and Mammals.UttamaTungkhang
This document compares and contrasts the respiratory systems of reptiles, birds, and mammals. It notes that all three use aerial respiration through lungs, but that some reptiles and birds undergo specialized adaptations related to their habitats. For example, crocodilians have a bony secondary palate for breathing underwater, while some lizards can increase stamina through buccal pumping. The document outlines key parts of the respiratory tract and how gas exchange occurs differently depending on the type of animal.
The document discusses the swim bladder, or air bladder, of fish. It is an internal gas-filled organ that contributes to a fish's ability to control buoyancy. There are two types - physostomous, which is directly connected to the digestive tract, and physoclistous, which is not connected. The basic structure includes a sac-like shape with two layers, an epidermis and endodermis. The swim bladder varies in shape and size between fish species and allows fish to rise and sink in water by increasing or decreasing the volume of gas inside without changing mass. Its key functions are to act as a hydrostatic organ, adjustable float, aid in respiration, produce sound, and maintain the fish's
The respiratory system of pigeons is highly developed to support flight. It includes a respiratory tract, lungs, and air sacs. The respiratory tract contains nostrils, nasal sacs, a larynx, trachea, and a syrinx vocal organ. The small lungs lack a diaphragm. Branched air sacs aid respiration and regulate body temperature. Respiration occurs via two cycles, with air drawn into posterior air sacs on the first breath and to anterior sacs on the second, providing double oxygenation of blood to support flight.
Chordates evolved in water with gill slits for respiration. Some moved to land using lungs and skin respiration. Reptiles used lungs and some used cloacal respiration. Birds evolved a unique lung system with air sacs. Mammals used refined lungs. Whales evolved from land mammals but returned to sea, keeping lungs for respiration but adapting for aquatic life.
The respiratory system of poultry includes nasal openings, nasal passages, trachea, bronchi, lungs, and air sacs. It differs from mammals in that poultry have complete tracheal rings, an organ of phonation at the trachea bifurcation rather than near the pharynx, fixed non-expanding lungs, and air sacs that extend into pneumatic bones. Respiration involves inspiration through bronchi and expiration through air sacs, facilitating gas exchange through the lungs. Thermoregulation occurs via radiation, conduction, convection, and evaporation from the respiratory tract.
The respiratory system obtains oxygen from the surroundings and conveys it to the body while removing carbon dioxide. It is linked to the circulatory system which transports oxygen using blood. In humans, breathing is driven by the diaphragm and intercostal muscles expanding the thorax, drawing air into the lungs which exchange gases via alveoli into the bloodstream. The lungs have branching airways ending in alveoli with a vast surface area for gas exchange.
The respiratory system of mammals is highly efficient for gas exchange. The lungs contain millions of alveoli that have a vast surface area due to their grape-like clustering. Air enters the lungs through the trachea and branches into smaller bronchioles before reaching the alveoli. Gas exchange occurs across the thin walls of the alveoli where oxygen passes into the blood and carbon dioxide passes out. The avian respiratory system is also very efficient, with unidirectional airflow through parabronchi and cross-current blood flow, allowing birds to respire at high altitudes.
The document summarizes the evolution of the respiratory system from early aquatic respiration through the skin to modern lung-based respiration in terrestrial animals. It describes how early aquatic animals used their skin and later gills for gas exchange, followed by the emergence of lungs for aerial respiration. It details the development of lungs across different vertebrate classes including mammals, birds, reptiles, amphibians and their associated structures like trachea. The document also discusses recent advances in respiratory physiology and diseases.
The document summarizes respiratory systems in animals. It describes how invertebrates like jellyfish respire through diffusion, while others use gills or tracheal tubes. Vertebrates either use gills for aquatic respiration with water flowing over them, or lungs for terrestrial animals. Lung structure varies between groups, with mammals having the most surface area for gas exchange. The human respiratory system uses the nose, mouth, lungs and alveoli to oxygenate blood and remove carbon dioxide.
Fish gills are highly folded organs located on the sides of the head that allow for efficient gas exchange. They have a network of capillaries and lamellae that divide the gill filaments, providing a large surface area for oxygen diffusion. The gills have a good blood flow and thin membranes that allow for countercurrent exchange, maximizing oxygen transfer from the water to the bloodstream.
The document summarizes the respiratory systems of various chordates. It describes how skin, gills, and lungs have evolved for respiration in different vertebrates. Skin respiration occurs mainly in amphibians like salamanders through their thin skin. Cartilaginous and bony fishes respire using gills consisting of pouches and slits. Lungs evolved from the swim bladder of early fish and are present in tetrapods, with variations in structure between amphibian, reptile, bird, and mammalian lungs.
Dr. P.B.Reddy provides an overview of the comparative anatomy of the vertebrate respiratory system. The document discusses why animals need to breathe and defines internal and external respiration. It then describes the key characteristics and functions of respiratory organs across different vertebrate groups, including fish, amphibians, reptiles and others. Specific structures are examined such as gills, lungs and the mechanisms of gas exchange that occur.
The respiratory system consists of organs and structures used for respiration. In mammals, respiration occurs through pulmonary ventilation via the nasal cavity, lungs, and diaphragm. The lungs exchange gases through alveoli and are protected by the rib cage. Horses and marine mammals have respiratory adaptations like nasal breathing and mechanisms to prevent water inhalation during dives.
The document discusses the respiratory system. It describes that the respiratory system brings oxygen into the body and removes carbon dioxide. It then describes the upper respiratory system, which includes the mucous membranes, mucous, cilia, pharynx, epiglottis, and larynx. The lower respiratory system is also described, including the trachea, bronchi, bronchial tree, bronchioles, alveoli, lungs, and diaphragm. The document also lists and defines several vocabulary terms related to respiration. Finally, it discusses the equine respiratory disease known as strangles, including its symptoms and methods for treatment and prevention.
Birds require large amount of oxygen due to their flight activity in accordance to which their respiratory system is comparatively more complex and developed.
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.
Comparative physiology of respiratory system of different speciesirfan khursheed
This document summarizes and compares the respiratory systems of different animal species. It discusses how mammals, reptiles, amphibians, birds, fish, and insects breathe. For mammals, the lungs are the main respiratory organ, using the diaphragm and rib muscles for breathing. Air enters the nose and travels through the epiglottis, trachea, bronchi, bronchioles, and alveoli where gas exchange occurs. Reptiles and amphibians also use lungs but some reptiles lack a diaphragm. Amphibians can pump air through buccal pumping. Birds have air sacs and force air through their lungs like bellows. Fish use gills to exchange gases.
Comparative Anatomy of Respiratory System of VertebratesRameshPandi4
The document discusses the comparative anatomy of the respiratory systems of various vertebrates. It describes how respiration occurs through the skin, gills, lungs, and gas bladders in different organisms. It explains key differences in respiratory structures between cartilaginous fishes, bony fishes, and jawless fishes. Mechanisms of gas exchange are covered for fishes, as well as respiratory organs and processes for amphibians, reptiles, birds, and mammals.
A Transmission Electron Microscopic Study of the Olfactory Epithelium in Hill...AI Publications
Olfaction is primarily produced by the stimulation of receptor cells on the olfactory organ's neuroepithelial surface, surrounded by olfactory nerve fibres. Numerous fish life processes, including migration, communication, feeding, schooling, defence, and reproduction, depend heavily on olfactory signals and cues. The olfactory and reproductory systems are interconnected structurally and functionally, and puberty-related alterations in the olfactory epithelium are documented. The olfactory epithelium, which covers a large portion of the surface of the olfactory rosette, a structure found within the olfactory chambers on the fish rostrum, is where the olfactory receptor cells are situated. Although ultra structural transmission electron microscopic studies of the olfactory organ and bulb are carried out by some investigators but very sparse information is available on hillstream fishes and that is why this work has been undertaken to detail the structure of olfactory system in G. mullya by electron microscopy. Microvillous olfactory receptor cells are placed compactly adjacent to the supporting cell showing a junction complex : the zonula-ocludens. Polygonal white cells are present in between the basal cells and supporting cells. Small polyhedral basal cells lie just above the basal lamina of olfactory epithelium. Basal cells may be working as stem cells for regeneration of lost or damaged non sensory and goblet cells.
This document describes a study on the vertical zonation and composition of meiofauna in Rearing Pond 2 of the Zamboanga State College of Marine Sciences and Technology. Meiofauna samples were collected from four stations at depths of 0-2cm, 2-4cm, 4-6cm, and 6-8cm below the sediment surface using a corer sampler. The samples were fixed with 5% formalin and sieved through 1mm and 250 micron meshes to extract the meiofauna. The goal of the study was to determine the meiofaunal composition and vertical distribution in the pond.
This document discusses a study that found molecular and morphological evidence suggesting that the flagellate Ancyromonas is closely related to the common ancestor of metazoans, fungi, and choanoflagellates. Analyses of 18S rRNA gene sequences from major eukaryotic lineages using maximum likelihood, minimum evolution, and maximum parsimony supported Ancyromonas forming its own lineage, called Ancyromonadida, that is more closely related to opisthokonts than its nearest protist relatives. However, low bootstrap support for deep nodes limits the ability of 18S rDNA to fully resolve this aspect of eukaryotic phylogeny.
This document describes the structure and mechanism of opening and closing the brood pouch in male pipefish, Trachyramphus bicoarctatus. The brood pouch consists of two lateral folds made up of three layers - an outer protective epithelium, a middle connective tissue layer, and an inner epithelial lining. The connective tissue layer contains muscles that relax to open the pouch and contract to close it. Fertilized eggs are arranged in strips inside the pouch. To close, the inner epithelial layer protrudes between the folds like an anchor and the folds gradually fuse together.
The fecundity of brackish river prawn (macrobrachium macrobrachion, herklots,...Alexander Decker
I. This study examined the fecundity of the brackish river prawn (Macrobrachium macrobrachion) from the Great Kwa River in Nigeria over a six month period.
II. The number of eggs ranged from 63 to 14,531 with a mean of 4,420.58 eggs per female. Egg diameters ranged from 0.26 to 0.38mm.
III. A strong positive correlation was found between female body size (weight, length, carapace length) and number of eggs. Fecundity increased linearly with body size.
This document discusses various respiratory organs in animals, including gills, book lungs, lungs, and skin. It provides details on lung structure and function in various vertebrates. Gas exchange occurs primarily through gills in fish, book lungs in spiders, and highly vascularized skin in amphibians. Advanced vertebrate lungs contain alveoli that increase surface area for gas exchange. Respiratory regulation involves centers in the medulla oblongata and pons. Locomotion and respiration are often synchronized across species.
Prevalence and morphological details of Nyctotherus periplanetae in the host ...IOSR Journals
Nyctotherus periplanetae is very common intestine dwelling ciliate in invertebrates. During the period of two years total number of 1842 intestinal samples of Periplaneta americana were checked. The percentage of prevalence of ciliates was found quite high and it was 57.77% during the year 2007 and 60.75% in 2008.
1) The document summarizes a study on the prevalence and morphological details of the ciliate Nyctotherus periplanetae found in the intestine of the cockroach Periplaneta americana.
2) Over two years, 1842 cockroaches were examined and the prevalence of N. periplanetae was found to be 57.77% in 2007 and 60.75% in 2008, with the highest rates occurring after monsoon rains.
3) Morphological analysis found N. periplanetae to be oval in shape, 100-175μ in length, with a straight cytopharynx, irregularly shaped macronucleus, and slit-like cytopy
1) The document summarizes a study on the prevalence and morphological details of the ciliate Nyctotherus periplanetae found in the intestine of the cockroach Periplaneta americana.
2) Over two years, 1842 cockroaches were examined and the prevalence of N. periplanetae was found to be 57.77% in the first year and 60.75% in the second year. Prevalence peaked after monsoon rains and was lowest during summer.
3) Morphological analysis found N. periplanetae to be oval shaped, 100-175μ in length, with a macronucleus, cytopharynx, and slit-like
In order to assess the Myxosporeans fauna of Cameroon fresh water fishes so
as to find the fight strategies, 655 specimens (350 Oreochromis niloticus and 305
Barbus callipterus) were sampled in Mapé river (Sanaga basin) and examined.
Standard methods were used for the sampling of fishes, conservation and microscopy.
Morphometric characteristics of the spores were used for species identification. Two
new species belonging to the genus Myxobolus Büstchli, 1882 were described namely
Myxobolus tchoumbouei n. sp in Barbus callipterus which formed cysts within various
organs (fins, skin and operculum); Myxobolus mapei n. sp parasite of kidneys and liver
in Oreochromis niloticus and Barbus callipterus. Myxobolus tchoumbouei exhibited
very long spores (19.19 x 8.89 μm), pear-shaped with rounded anterior end
sometimes flattened. Polar capsules were dissymmetrical. They measured 7.60 x 3.00
μm for the bigger and 7.06 x 2.62 μm for the smaller. Myxobolus mapei n. sp had
ellipsoidal spores (13.50 x 6.83 μm) with unequal polar capsules. The larger polar
capsule (6.44 X 2.88 μm) was about 1.5 times longer than the smaller one (4.13 X 1.61
μm) and filled half of the spiral cavity. The awareness about these parasites is useful
to find fighting strategies.
This document describes several medically important arthropods including flies, sandflies, fleas, and cockroaches. It provides details on their classification, morphology, life cycles, behaviors, and roles in disease transmission. Regarding flies, it notes that houseflies can transmit pathogens mechanically and cause myiasis. For sandflies, it identifies several disease-transmitting species and describes their morphology, life cycle, and medical importance in transmitting leishmaniasis. Fleas are described as ectoparasites of mammals that can cause irritation and transmit plague and epidemic typhus. Control methods for these arthropods focus on environmental modification and use of insecticides.
Ultrastructural Study of two Parasites Infecting Domesticated Turkey Meleagri...IOSRJPBS
This work provides a detailed systematic morphology by optic and Scanning electron microscopy of two parasites Raillietina echinobothriida Megnin, 1880 and Spirora meleagaris n. sp. infecting domesticated turkey. The present study includes some important characters that not recorded in previous description. SEM revealed that the tegument of the first cestode exhibits, filamentous, microtriches and sensory papillae densely covered the tegument of entire body, rostellum armed with two rows of hummer-shaped hooks and provide by 16 – 20 rows of small, rose thorn-shaped accessory spines. In addition, the present studies have observed a number of taxonomic features in Spirora meleagaris n. sp. that differ from those mentioned in the same genus, mouth circular, bounded by a cuticular three circles plates, five pairs of cephalic papillae, an inner circle of two pairs situated on the wall of the buccal cavity, one pair of larges submedian amphids, and an outer circle of two pairs papillae. Buccal cavity supported by four chitinious cusped molar teeth anteriorly directed .Vulva near the end of the first third of the body, vulvular lips prominent. The male has unique rose like shaped pedunculated and unarranged numerous distributed sessile cervical papillae at the second third of the body that are distinguishable from other spirorid.
This document describes the classification, morphology, behaviors, and medical importance of flies, sandflies, fleas, and cockroaches. It notes that flies belong to the order Diptera and includes disease-transmitting species like houseflies. Sandflies are in the order Psychodidae and can transmit leishmaniasis. Fleas are ectoparasites that belong to the order Siphonaptera and transmit plague and epidemic typhus. All four undergo complete metamorphosis from egg to larva to pupa to adult. As vectors, they can transmit pathogens mechanically or biologically and cause diseases and infections in humans. Prevention focuses on environmental modification and use of insecticides, screens, and personal protection measures
This document describes the sequencing and analysis of the small subunit ribosomal RNA gene from an unusual form of the protistan parasite Ichthyophonus found infecting yellowtail flounder off Nova Scotia. Phylogenetic analysis shows it is distinct from two isolates of I. hoferi, supporting it being a separate species named I. irregularis. This finding raises the possibility that ichthyophoniasis in fish could be caused by different but related pathogens, in some cases concurrently.
This document summarizes a study characterizing the algal mats and flora of El-Timsah Lake during spring 2004-2005. Two main types of algal mats were observed - a green mat composed primarily of Cladophora filaments with diatoms, and a black mat composed of Oscillatoria nigroviridis cyanobacteria with diatoms. Physicochemical parameters like temperature, pH, salinity and nutrients supported growth of brackish and eutrophic species. A total of 31 algal taxa from 5 divisions were identified. Formation of the algal mats during late winter-early spring is related to the lake's limnological features, including muddy sediments, brackish
- The skin of amphibians undergoes significant changes during postembryonic development, including changes in structure, thickness, and gland composition.
- In the crested newt Triturus ivanbureschi, the skin transitions from a single layer of cells in hatchlings to a stratified epithelium with four cell layers in late larvae, developing Leydig cells and gland nests.
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Five ectoparasites were collected from fish in Turkey between 2002-2005: four crustaceans (Ergasilus mosulensis, Pennella instructa, Ceratothoa steindachneri, and Argulus foliaceus) and one annelid (Piscicola geometra). E. mosulensis, P. instructa, and C. steindachneri are reported for the first time in Turkish waters, and A. foliaceus and P. geometra are reported for the first time from Çavuşçu Lake. The parasites were collected from various fish hosts in the Mediterranean Sea, Aegean Sea, and inland waters of Turkey
Development of techniques for the cultivation of lessonia trabeculata.etcIvan Vera Montenegro
This document discusses the development of techniques for cultivating Lessonia trabeculata in Chile. Small sporophytes of L. trabeculata were propagated in the laboratory from reproductive blades and cultured on different substrates like nylon cord and PVC tubes. The algae were grown in outdoor tanks and then transferred to long lines in the ocean, where individual plants reached up to 1.7 kg in mass. When tested, abalone grew as well on the cultured L. trabeculata as on naturally occurring algae, demonstrating its potential as a sustainable food source for abalone aquaculture.
This document summarizes a histological study comparing the brooding structures in two subfamilies of brachiopods: Lacazellinae and Thecidellininae. The study found that in Lacazellinae, larvae are attached to two specialized tentacles inside a median brood pouch located in the ventral valve. In Thecidellininae, larvae develop in two lateral brood pouches located in the dorsal valve. Despite morphological differences, both brooding structures originate from lophophoral epithelium, suggesting they are homologous. The study provides the first detailed examination of brooding tissue development in these brachiopod groups.
Evaluation and Identification of J'BaFofi the Giant Spider of Congo and Moke...MrSproy
ABSTRACT
The J'BaFofi, or "Giant Spider," is a mainly legendary arachnid by reportedly inhabiting the dense rain forests of
the Congo. As despite numerous anecdotal accounts and cultural references, the scientific validation remains more elusive.
My study aims to proper evaluate the existence of the J'BaFofi through the analysis of historical reports,indigenous
testimonies and modern exploration efforts.
Microbial interaction
Microorganisms interacts with each other and can be physically associated with another organisms in a variety of ways.
One organism can be located on the surface of another organism as an ectobiont or located within another organism as endobiont.
Microbial interaction may be positive such as mutualism, proto-cooperation, commensalism or may be negative such as parasitism, predation or competition
Types of microbial interaction
Positive interaction: mutualism, proto-cooperation, commensalism
Negative interaction: Ammensalism (antagonism), parasitism, predation, competition
I. Mutualism:
It is defined as the relationship in which each organism in interaction gets benefits from association. It is an obligatory relationship in which mutualist and host are metabolically dependent on each other.
Mutualistic relationship is very specific where one member of association cannot be replaced by another species.
Mutualism require close physical contact between interacting organisms.
Relationship of mutualism allows organisms to exist in habitat that could not occupied by either species alone.
Mutualistic relationship between organisms allows them to act as a single organism.
Examples of mutualism:
i. Lichens:
Lichens are excellent example of mutualism.
They are the association of specific fungi and certain genus of algae. In lichen, fungal partner is called mycobiont and algal partner is called
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It is an association in which the growth of one organism either depends on or improved by the substrate provided by another organism.
In syntrophism both organism in association gets benefits.
Compound A
Utilized by population 1
Compound B
Utilized by population 2
Compound C
utilized by both Population 1+2
Products
In this theoretical example of syntrophism, population 1 is able to utilize and metabolize compound A, forming compound B but cannot metabolize beyond compound B without co-operation of population 2. Population 2is unable to utilize compound A but it can metabolize compound B forming compound C. Then both population 1 and 2 are able to carry out metabolic reaction which leads to formation of end product that neither population could produce alone.
Examples of syntrophism:
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Methane produced by methanogenic bacteria depends upon interspecies hydrogen transfer by other fermentative bacteria.
Anaerobic fermentative bacteria generate CO2 and H2 utilizing carbohydrates which is then utilized by methanogenic bacteria (Methanobacter) to produce methane.
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The synergistic relationship between E. faecalis and L. arobinosus occurs in which E. faecalis require folic acid
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
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Centrifugation is a powerful technique used in laboratories to separate components of a heterogeneous mixture based on their density. This process utilizes centrifugal force to rapidly spin samples, causing denser particles to migrate outward more quickly than lighter ones. As a result, distinct layers form within the sample tube, allowing for easy isolation and purification of target substances.
Presentation of our paper, "Towards Quantitative Evaluation of Explainable AI Methods for Deepfake Detection", by K. Tsigos, E. Apostolidis, S. Baxevanakis, S. Papadopoulos, V. Mezaris. Presented at the ACM Int. Workshop on Multimedia AI against Disinformation (MAD’24) of the ACM Int. Conf. on Multimedia Retrieval (ICMR’24), Thailand, June 2024. https://doi.org/10.1145/3643491.3660292 https://arxiv.org/abs/2404.18649
Software available at https://github.com/IDT-ITI/XAI-Deepfakes
Dr. Firoozeh Kashani-Sabet is an innovator in Middle Eastern Studies and approaches her work, particularly focused on Iran, with a depth and commitment that has resulted in multiple book publications. She is notable for her work with the University of Pennsylvania, where she serves as the Walter H. Annenberg Professor of History.
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Context. The observation of several L-band emission sources in the S cluster has led to a rich discussion of their nature. However, a definitive answer to the classification of the dusty objects requires an explanation for the detection of compact Doppler-shifted Brγ emission. The ionized hydrogen in combination with the observation of mid-infrared L-band continuum emission suggests that most of these sources are embedded in a dusty envelope. These embedded sources are part of the S-cluster, and their relationship to the S-stars is still under debate. To date, the question of the origin of these two populations has been vague, although all explanations favor migration processes for the individual cluster members. Aims. This work revisits the S-cluster and its dusty members orbiting the supermassive black hole SgrA* on bound Keplerian orbits from a kinematic perspective. The aim is to explore the Keplerian parameters for patterns that might imply a nonrandom distribution of the sample. Additionally, various analytical aspects are considered to address the nature of the dusty sources. Methods. Based on the photometric analysis, we estimated the individual H−K and K−L colors for the source sample and compared the results to known cluster members. The classification revealed a noticeable contrast between the S-stars and the dusty sources. To fit the flux-density distribution, we utilized the radiative transfer code HYPERION and implemented a young stellar object Class I model. We obtained the position angle from the Keplerian fit results; additionally, we analyzed the distribution of the inclinations and the longitudes of the ascending node. Results. The colors of the dusty sources suggest a stellar nature consistent with the spectral energy distribution in the near and midinfrared domains. Furthermore, the evaporation timescales of dusty and gaseous clumps in the vicinity of SgrA* are much shorter ( 2yr) than the epochs covered by the observations (≈15yr). In addition to the strong evidence for the stellar classification of the D-sources, we also find a clear disk-like pattern following the arrangements of S-stars proposed in the literature. Furthermore, we find a global intrinsic inclination for all dusty sources of 60 ± 20◦, implying a common formation process. Conclusions. The pattern of the dusty sources manifested in the distribution of the position angles, inclinations, and longitudes of the ascending node strongly suggests two different scenarios: the main-sequence stars and the dusty stellar S-cluster sources share a common formation history or migrated with a similar formation channel in the vicinity of SgrA*. Alternatively, the gravitational influence of SgrA* in combination with a massive perturber, such as a putative intermediate mass black hole in the IRS 13 cluster, forces the dusty objects and S-stars to follow a particular orbital arrangement. Key words. stars: black holes– stars: formation– Galaxy: center– galaxies: star formation
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSSérgio Sacani
The pathway(s) to seeding the massive black holes (MBHs) that exist at the heart of galaxies in the present and distant Universe remains an unsolved problem. Here we categorise, describe and quantitatively discuss the formation pathways of both light and heavy seeds. We emphasise that the most recent computational models suggest that rather than a bimodal-like mass spectrum between light and heavy seeds with light at one end and heavy at the other that instead a continuum exists. Light seeds being more ubiquitous and the heavier seeds becoming less and less abundant due the rarer environmental conditions required for their formation. We therefore examine the different mechanisms that give rise to different seed mass spectrums. We show how and why the mechanisms that produce the heaviest seeds are also among the rarest events in the Universe and are hence extremely unlikely to be the seeds for the vast majority of the MBH population. We quantify, within the limits of the current large uncertainties in the seeding processes, the expected number densities of the seed mass spectrum. We argue that light seeds must be at least 103 to 105 times more numerous than heavy seeds to explain the MBH population as a whole. Based on our current understanding of the seed population this makes heavy seeds (Mseed > 103 M⊙) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10−4 compared to light seeds. Finally, we examine the current state-of-the-art in numerical calculations and recent observations and plot a path forward for near-future advances in both domains.
This presentation offers a general idea of the structure of seed, seed production, management of seeds and its allied technologies. It also offers the concept of gene erosion and the practices used to control it. Nursery and gardening have been widely explored along with their importance in the related domain.
Mechanics:- Simple and Compound PendulumPravinHudge1
a compound pendulum is a physical system with a more complex structure than a simple pendulum, incorporating its mass distribution and dimensions into its oscillatory motion around a fixed axis. Understanding its dynamics involves principles of rotational mechanics and the interplay between gravitational potential energy and kinetic energy. Compound pendulums are used in various scientific and engineering applications, such as seismology for measuring earthquakes, in clocks to maintain accurate timekeeping, and in mechanical systems to study oscillatory motion dynamics.
1. J. vet. anat. Vol 1 No1, (2008) 29 - 3729
Air breathing organ in catfish Ahmed et al.
Anatomical, Light and Scanning Electron Microscopic Studies on
the Air Breathing Dendretic Organ of the Sharp Tooth Catfish
(Clarias gariepinus)
Abd-Elmaksoud Ahmed1
, Kassab Mohamed2
, Sayed-Ahmed Ahmed3,
Fayed Masoud 4
1 Department of Cytology and Histology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
2 Department of Histology, faculty of veterinary medicine, Kafr El Sheikh University, Kafr El Sheikh, Egypt
3 Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Alexandria University, Damanhur branch, Bostan, Egypt
4 Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Kafr El Sheikh University, Kafr El Sheikh, Egypt
E-mail: kassabkassab2000@yahoo.com
___________________________________________________________________________
With 20 figures Received February 2008; accepted for publication April 2008
Abstract
Previously, it has been shown that different species
of fishes are adapted in varying degrees for gaseous
exchange in both water and air. Our study was
carried out on sharp tooth catfish (Clarias garie-
pinus) obtained from the Nile River, Egypt and fo-
cused on the dendretic organ (DO) investigating its
anatomical, scanning and light microscopical fea-
tures. Anatomically, the air-breathing dendretic
organ of the catfish was located in the suprabran-
chial chamber caudodorsal to the gills and com-
posed of two main parts; small and large ones origi-
nated by main stems from the second and fourth gill
arches respectively. Histologically, the DO either in
its main stems or in the smaller branches and in the
end bulbs consists of core of elastic cartilage, vas-
cular layer of connective tissue and covering epithe-
lium containing intraepithelial mucous glands. The
blood capillaries (channels) were found to originate
from the vascular layer and penetrate the covering
epithelium. Toward the surface, these capillaries
dilate and bulge out due to engorgement with RBCs
forming what is called respiratory papillae. The SEM
showed that the stem divisions and their bulbus
ends contained double parallel rows of paired pro-
jections (respiratory lamellae) separated by areas of
smooth surface. Moreover, the surfaces were stud-
ded with microvilli. In conclusion, the structure of this
organ manifests profuse internal subdivision that
may produce a particularly large respiratory surface
area to extract the oxygen from air. Therefore, the
catfish might be one of the most suitable fish for the
intensive production in the fish aquaculture.
Key Words
Dendretic organ, Catfish, E/M
Introduction
The sharp tooth catfish (Clarias garipeinus) is one of
the most important fresh water fishes in the River
Nile in Egypt. It has a great economic impor
tance, contributing about 17.5 % of the total country
catch (GAFRD, 1996). Most fishes obtain oxygen
from water using efficient gills, but low oxygen solu-
bility in water limits oxygen availability. To cope with
hypoxic water, some fishes swim to the surface and
take in the oxygen-rich water at the interface, while
others have evolved the ability to breath atmospheric
air (Liem, 1967; Mittal and Munshi, 1971; Mittal and
Banerjee, 1974; Mittal et al. 1980; Suzuki, 1992;
Graham, 1997; Ishimatsu et al. 1998; Park et al.
2000; Zhang et al. 2000; Park, 2002). The air respi-
ration in fishes could be done either through swim
bladder as Bowfin (Amia calva) (Gervais and Tufts,
1998) and Arapaima gigas (Brauner et al., 2004), or
through the skin as in mudskipper (Periophthalmus
magnuspinnatus) (Park, 2002), or through the ac-
cessory respiratory organ as in cat fish (clarias
garipinus ) (Nawar, 1955; Moussa, 1956 and 1957;
Vandewalle and Chardon, 1991;), cat fish (clarias
mossambicus) (Maina and Maloiy 1986) and cat fish
(clarias batrachus ) (Munshi, 1961; Lewis, 1979).
and Climbing perch (Anabas testudineus) (Munshi et
al., 1986). The Clariidae is a bottom feeding omni-
vore (Bishai and Khalil 1997) that has a wide geo-
graphical distribution and inhabitant tropical swamps
and rivers which are liable to seasonal drying. To
survive in such habitats, with changing oxygen
tension, this group of fish has acquired a bimodal
gas exchange capacity wherein the gill extract oxy-
gen from water and the accessory respiratory organ
extract it from air (Nawar, 1955; Moussa, 1956 and
1957; Munshi 19961; Vandewalle and Chardon,
1991; Bishai and Khalil 1997; Graham, 1997; Chan-
2. J. vet. anat. Vol 1 No1, (2008) 29 - 3730
Air breathing organ in catfish Ahmed et al.
dra and Banerjee, 2003). Briefly, the air breathing
organs not only enable the fish to survive in hypoxic
water but also permit them to stay out of the water
for hours at a time (Chandra and Banerjee, 2003).
Previously, the respiratory organs have been
studied in some of the closely related catfishes such
as Clarias batrachus ((Munshi, 1961; Lewis, 1979;
Chandra and Banerjee, 2003), and Clarias mossam-
bicus (Johnston et al., 1983 Maina and Maloiy 1986),
wherein it is formed of aquatic breathing organ (gills)
and aerial breathing organs. The accessory respira-
tory organs (aerial breathing organs) are repre-
sented by dendretic organ (labyrinthine or arbores-
cent organ), fan organ and the epithelium lining the
membrane of the suprabranchial chamber (Maina
and Maloiy 1986; Chandra and Banerjee, 2003).
Although several approaches have previously inves-
tigated the morphology and physiology of the respi-
ratory organs of the sharp tooth cat fish (Clarias
garipeinus) in Egypt (Nawar 1955; Moussa 1956,
1957; Zayed and Mohamed 2004), none of these
studies paid detailed attention to the structures of the
dendretic organ of this species. Therefore, our study
aims to shed light on the anatomical, light and scan-
ning microscopical features of the dendretic organ of
catfish (Clarias garipeinus).
Materials and methods
This study was carried out on 10 apparently healthy
mature fishes. The fish weight ranged from 500-1500
gm and measured 30-45 cm in length. Five fishes
were used to demonstrate the gross morphological
features. After catching the fishes from the River
Nile, they were transported in dry plastic aquaria to
our lab in 2-3 hours to allow the aerial respiration.
Firstly, the fishes were sacrificed and then the oper-
cular cavity was opened. The gill and associated
accessory respiratory organs were examined in situ
and then dissected and photographed by Sony
digital camera.
For light microscopic study, small samples (0.3-0.5
mm
3
) of the dendretic organ were taken from three
fishes. The samples were fixed in Bouin’s solution
for 18-24 hrs. After fixation, the samples were exten-
sively washed in 70 % alcohol (3 x 24 hr) to get rid of
the fixative before the subsequent step of tissue
processing. The tissue samples were then dehy-
drated in graded series of ethanol (80%, 95% and
absolute), cleared in xylene and impregnated and
embedded in paraffin wax. Sections of 5-7 m were
cut using Leica rotatory microtome (RM 2035) and
mounted on glass slides. Paraffin sections were kept
in incubator at 40°C until used for conventional
staining (H&E, Massons Tricrome, Verhoeff’s, Go-
mori’s, PAS, and AB pH 2.5). All of the staining
techniques employed were performed according to
Bancroft and Steven (1990).
For scanning electron microscopic study,
two fishes were used. Small samples from different
parts of the dendretic organ were taken. The sam-
ples were fixed in a mixture of paraformaldehyde 2.5
% and glutaraldehydehyde 2.5 % solution in 0.1 M
phosphate buffer for 4 hours at 4°C. After washing in
the same buffer, the specimens were post-fixed in
osmiumtetroxide 1% in phosphate buffer for two
hours followed by washing in the same buffer. The
samples were then dehydrated in ascending grades
of ethanol followed by critical point drying in carbon
dioxide, then sputter-coated with gold and examined
with Jeol JSM 5300 scanning electron microscope,
Faculty of Science, Alexandria University.
Results
Our results were focused on the anatomical, scan-
ning and light microscopical features of the den-
dretic organ (DO) of sharp tooth cat fish Clarias
gariepinus (Fig. 1) and descried in details as follow:
The Anatomical features
The air-breathing dendretic organ of the catfish was
located in the suprabranchial chamber caudodorsal
to the gills and covered wholly by the membrane
lining the suprabranchial chamber (Fig. 2). Removal
of this membrane was shown that the dendretic
organ is additionally covered rostrally by fan-like
structures projected from the first, second and third
gill arches (Figs. 2, 3, 4). Structurally DO was divided
into two parts; small anterior part and large posterior
part that originating from the proximal end of the 2
nd
and 4
th
branchial arches respectively (Figs. 3, 4).
The size of the anterior small part represented nearly
50 % of the large one and occupied the majority of
the anterior compartment of the suprabranchial
chamber. The large posterior part occupied the
majority of the middle and posterior compartments of
the suprabranchial chamber. Both of the anterior and
posterior part was connected to its corresponding gill
arch by cartilaginous joint and originated by small
smooth surface main stem which further divided into
a number of secondary branches (Fig. 5). The main
stem of small part of the dendretic organ has 3
secondary branches while the large one was divided
into 4-5 branches. The secondary branches of both
anterior and posterior parts repeatedly divided into
small ones in dichotomous branching to end in
bulbus like structure (bulbus terminals). This archi-
tecture made the organ in the form of a tree –like
structure (dendretic structure) (Figs. 3, 4, 5).
Light Microscopy
Histologically, the DO either in its main stem or in
the smaller branches and in the end bulb consists of
definite structures represented by a core of elastic
cartilage, vascular layer of connective tissue and
3. J. vet. anat. Vol 1 No1, (2008) 29 - 3731
Air breathing organ in catfish Ahmed et al.
covering epithelium of stratified type (Figs. 6,7, 8).
The cartilaginous core was covered externally by a
thick layer of perichondrium which composed mainly
of elastic and collagen fibers. In contrast to the
normal elastic cartilage which is a vascular, the
perichondrium penetrates inside the cartilaginous
core carrying the blood vessels (Fig. 6). This archi-
tecture may demarcate the divisions of the cartilage
into the smaller branches of the DO. Internally, the
core was found to consist of, chondrocytes, network
of elastic fibers, blood vessels, and small collections
of fat cells (Fig. 7). The vascular connective tissue
layer was shown to consist of large blood vessels
(arteries and veins), connective tissue fibers (colla-
gen and reticular) and connective tissue cells, mainly
fibroblasts. The large blood vessels were found to
further branch into smaller ones to end finally in
blood channels (capillaries) (Fig. 9). The latter pene-
trate the covering epithelium in a regular manner, as
they were separated by 2 epithelial cells thick (pillar
cells). Moreover, these capillaries were found to
dilate and bulge out toward the surface due to en-
gorgement with RBCs forming what is called respira-
tory papillae (Figs. 10, 11). The covering epithelium
was shown to consist predominantly of stratified
epithelium rest on basal lamina. Intraepithelial mu-
cous glands clearly stained with PAS and AB was
also seen within the covering epithelium. These
glands were lined by cuboidal cells containing flat-
tened nuclei near its basal lamina (Figs. 9, 11, 12).
SEM
The arborization of the dendretic organ was like
cauliflowers. There were branches of bulbus-like
structure arisen from the stem divisions (Fig. 13).
Generally, the surface of the stem divisions and their
bulbus ends were found to contain transversely
oriented folds (respiratory lamellae) separated by
intervening spaces. These folds are papillae like-
structures which projected over the surface and
arranged in several parallel rows. However, the
double parallel rows of stem divisions separated by
wide areas of smooth surface while the interlamellar
space was narrow (Figs. 14, 15). Moreover, the
epithelium between the paired lamellae contained
mucus arisen from the intraepithelial mucous gland
(Fig. 15). On the other hand, the paired lamellae of
the bulbus end was found to differ from that of the
stem divisions, where they were high, crowded and
separated by a comparatively narrow space (Figs.
14, 15). The interlamellar space of the bulbus end
was also very small comparing with that of the stem
divisions (Figs. 16, 17). The covering epithelium of
the respiratory lamellae and the spaces in between
was studded with microvilli and the opening of the
intraepithelial mucous gland were clear (Figs. 17,
18).
In cross section of the bulbus end, the core con-
tained connective tissue fibers separated by narrow
spaces. At the periphery of the core, large blood
spaces were additionally seen just beneath the
epithelium. These blood spaces contained tongue-
like projections originated from its endothelium and
protruded into the lumen from tissue side toward the
periphery (Figs. 19, 20).
Discussion
Our study on the sharp tooth cat fish Clarias gerie-
pinus has revealed that the dendretic organ was
completely covered by suprabranchial membrane
and partially by fan-like structures. Previously, all of
these structures were descried as air-breathing
organs in walking catfish Clarias batrachus (Munshi
1961; Olson et al.1995). However, this fact needs
further studies on the fish under investigation. The
dendretic part of the air-breathing organ of the cat
fish Clarias geriepinus is derived from the 2
nd
and 4
th
gill arches. These findings are coordinate well with
the findings of the previous investigations in Siluroi-
dei clarias and Heterobranchus (Harder, 1975),
Clarias batrachus (Munshi, 1961; Lewis, 1979;
Chandra and Banerjee, 2003), Clarias mossambicus
(Johnston et al 1983 Maina and Maloiy 1986) and in
Clarias geriepinus (Moussa 1956; Zayed and Mo-
hamed 2004). On the contrary the dendretic organ
of Anabantoidei and Perciformes (Harder, 1975) and
Channa punctata and Channa striatus (Munshi
1962) was originated from the 1
st
gill arch only.
There is some similarities between the dendretic
organ and the gills; the gaseous exchange surfaces
of the dendretic organ consists of double rows of
paired lamellae (biserial arrangement), a feature
strongly indicative of their common origin from the
gills. However, and in contrast to the epithelial cells
surface of the dendretic organ which has numerous
small projections that consists of microvilli, the sur-
face of gill cells has numerous concentric whorls of
micro-ridges (Lewis 1979). These structural differ-
ences may attribute to the different mechanisms of
respirations (aquatic and aerial). Additionally, the
entire dendretic organ including its bulbus terminals
has additional support of an internal cartilaginous
core, which prevents collapse of the respiratory
lamellae when the fish faces the loss of water due to
dehydration during air exposure. This keeps the
respiratory surfaces freely exposed, so that the fish
can continues aerial exchange of gases for fairly
long periods. Interestingly, the aforementioned
structural adjustment may be one of the main rea-
sons for the comparatively better aerial performance
of the dendretic organ compared to the gills (Chan-
dra and Banerjee 2003).
The double rows of paired lamellae on the dendretic
organ are crowded in the bulbus ends and sepa-
rated by little space while that of the main stem are
widely separated. These results indicate that the
main respiratory part is confined to the bulbus ends.
4. J. vet. anat. Vol 1 No1, (2008) 29 - 3732
Air breathing organ in catfish Ahmed et al.
Furthermore, the presence of microvilli on the sur-
face of the respiratory lamellae and in between may
serve to trap bacteria or particulate manner and to
humidify the air (Munshi et al. 1986). Our results
were shown an enormous increase in the number of
RBCs in the blood channels and in the underlying
blood vessels. These results is supported by the fact
that, following air exposure, engorgement of the
blood channels causes them to stretch and dilate,
especially those at the tips of bulbus end (respira-
tory lamellae) resulting in either finger like projec-
tions (Chandra and Banerjee 2003), or balloon like
projections (Parashar and Banerjee 1999) or globu-
lar shape projections (Banerjee and Chandra 2005)
onto the surface of the dendretic organ. The load on
these thin–walled tubular structures thus increases
resulting in bending of these blood capillaries (chan-
nels) at 90° to rest flat on the surface of dendretic
organ. All these structural adaptation narrow the
barrier distance between the atmospheric air in the
suprabranchial chamber and the blood in the respi-
ratory lamellae of the dendretic organ which may be
a compensatory measure to the failure of branchial
respiration (Chandra and Banerjee, 2003; Banerjee
and Chandra,2005). The endothelial cells of the
transverse blood channels have unusual structural
modifications, which are tongue-like projections in
the lumen directed from tissue side toward the sur-
face side. This finding suggests that their shape is
governed by the direction of blood flow through the
channels (Munshi et al. 1986). Moreover, Hughes
and Munshi (1978) supposed that, these processes
act as valves controlling the flow of blood through
the channels. They also point out that the tongue-
like extensions may act as an obstacle to RBCs and
force them to flow over the top of the extensions.
This would place the RBCs in closest proximity to
the respiratory surface and reduce the air-blood
diffusion distance and maximize gas transfer (Mun-
shi et al. 1986).
In our study the intraepithelial mucous glands were
showed to contain neutral and/or acidic mucopoly-
saccharides as indicated by PAS and AB stains.
This result ascertains the mucous nature of the
respiratory surface of the gills and dendretic organs
of the catfish Clarias gariepinus (Zayed and Mo-
hamed 2004) and Clarias mossambicus (Johnston
et al., 1983; Maina and Maloiy 1986). Continuous
elaboration of this mucous over the surface epithe-
lium of the respiratory organs keeps the surfaces
moist and clean as the mucus facilitates the removal
of the trapped intoxicating agents, pathogen and
foreign materials when the fishes live outside the
water. Additionally, this mucous is important not only
as a protective barrier but also has an ion regulatory
function (Handy et al, 1989). Taken together, mu-
cous glands help in the extension of the survival
period after air exposure where during the initial
period the mucous cell showed periodic fluctuations
in their density and staining properties and stained
for sulphated mucopolysaccharides that known to
hold an additional quantity of water to keep the
surface moist for long period (Chandra and Banerjee
2004). However, the protective role played by the
slime coating does not last for long time as the
mucous glands and its cells become exhausted and
degenerate (Chandra and Banerjee 2003, 2004).
Although the catfish Clarias gariepinus has a smaller
gill surface area than the Nile tilabia (Zayed and
Mohamed 2004), it can survive for long period either
in the hypoxic water or outside the aquatic environ-
ment (Chandra and Banerjee, 2004). This fact might
be partially explained by the presence of the den-
dretic organ in the catfish. Such notion is supported
by the observation of Sigh and Huges, (1971) who
reported that the catfish Clarias batrachus even
when kept in aerated water it obtains 58% of its
oxygen from air. Moreover, the catfish clarias mos-
sambicus is entirely dependent for survival on its
capacity to breathe atmospheric oxygen (Johnston
et al., 1983). Importantly we should know that air
breathing does not help the fish to survive for unlim-
ited period, and the fish ultimately die due to failure
of respiration, hemorrhage , and collapse of many
other important physiological processes (CO2 and
N2 elimination) even though the air-breathing organ
continue to absorb small amount of O2 aerially. In
other words, while O2 absorption is the dominant
feature of air breathing, the aquatic breathing re-
mains very important for CO2 and N2 elimination
(Chandra and Banerjee 2003).
In conclusion, the catfish can survive for long period
either in the hypoxic water or outside the aquatic
environment due to the presence of the dendretic
organ. The structure of this organ manifests profuse
internal subdivision that may produce a particularly
large respiratory surface area to extract the oxygen
from air. Therefore, the catfish might be one of the
most suitable fish for the intensive production in the
fish aquaculture.
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Fig. 1: Photograph of the sharp tooth catfish Clarias gariepinus.
Fig. 2: Photograph of the ventral part of head region with exposed gill chambers and associated air breathing
organs showed gill (G), gill fan (F), membrane covering suprabranchial chamber (arrow) and dendritic organ
(DO).
Fig. 3: The gill system and associated air breathing organs showed gill arches (1, 2, 3, 4 and 5), gill fan (F),
small part of dendritic organ (SDO) and large part of dendritic organ ( LDO).
Fig. 4: The gill system and associated air breathing organs showed gill arches (1, 2, 3, 4 and5), gill fan (F),
small part of dendritic organ (SDO) and large part of dendritic organ ( LDO).
7. J. vet. anat. Vol 1 No1, (2008) 29 - 3735
Air breathing organ in catfish Ahmed et al.
Fig. 5: Connection of large part of dendritic organ and 4
th
gill arch (G), cartilaginous joint (black arrow) main
stem (S) and secondary branches (white arrow).
Fig. 6: Paraffin section of the main stem of the DO showed the covering epithelium (E), connective tissue
(CT), artery (A) and elastic cartilage (EC). H&E X40.
Fig. 7: The cartilaginous core of the main stem (EC) contains connective tissue trabeculae (CT) with fat cells
(F). Verhoeff’s elastic stain, X100
Fig. 8: Paraffin section of the bulbus terminals showed epithelium (E), connective tissue (CT), elastic cartilage
(EC), perichondium (P), CT septa (S), blood vessels (BV), and chondrocytes (arrow). H&E X100.
Fig. 9: Paraffin section of the DO showed blood channels (black arrow) originated from blood vessels (BV)
and penetrated the covering epithelium (E) which contains intraepithelial mucous gland (M). H&E X400.
Fig. 10: Toward the surface, the blood channels were dilated (arrow) due to engorgement with RBCs and se-
parated by two epithelial cell thick (E). H&E, X1000.
8. J. vet. anat. Vol 1 No1, (2008) 29 - 3736
Air breathing organ in catfish Ahmed et al.
Fig. 11: Epithelium of bulbus end (E) showed vascular papillae (arrow) and mucous gland (M). H&E X1000.
Fig. 12: PAS positive intraepithelial mucous gland (arrow). PAS, X600
Fig. 13: Scanning electron micrograph of cauliflower-shaped DO showed stem (S) and bulbus end (B).
Fig. 14: Higher magnification to the previous showed double parallel rows of respiratory lamellae (black and
white arrow) on the stem (S) and bulbus end (B) respectively.
Fig. 15: Higher magnification of double parallel rows of respiratory lamellae (arrow) on the stem (S) with epi-
thelial surface (ES) in between contained mucus (white arrow head).
Fig. 16: Higher magnification of double parallel rows of respiratory lamellae (RL) on the bulbus end and the
intervening space in between (arrow).
9. J. vet. anat. Vol 1 No1, (2008) 29 - 3737
Air breathing organ in catfish Ahmed et al.
Fig. 17: Scanning electron micrograph of bulbus end showed the respiratory epithelium (RE) in between the
respiratory lamellae (RL).
Fig. 18: Higher magnification of the respiratory lamellae (RL) showed microvilli on its surface and opening of
the mucous gland (arrow).
Fig. 19: Scanning electron micrograph of cross section of the bulbus end showed connective tissue core (CC)
and blood vessels (BV). Note the respiratory lamellae on the surface (arrow).
Fig. 20: Higher magnification of figure 19 showed tongue-like protrusion (arrow) inside the blood vessels.
Address for correspondence Dr. Mohamed Kassab, Department of Cytology and Histology, Faculty of Veteri-
nary Medicine, Kafr El Sheikh University, Kafr El Sheikh, Egypt