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Wednesday, 19 April 2017 01:49
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Aurelia is also called as jellyfish. This jelly fish is umbrella shaped with outer ex-umbrellar surface and inner sub-umbrella surface.
In the middle of the sub-umbrellar surface a tetra angular mouth is present. It leads into a short gullet within the manubrium. It leads into a wide stomach. This stomach will show 4 gastric pouches on the 4 inter radial positions. In each gastric pouch may gastric filaments are present. These gastric filaments bear cnidoblasts.
From the four corners of the mouth 4 oral arms will arise. These arms are long and perradial in position.
On the ventral side of each arm in the middle a ciliated groove is present. This groove leads into mouth. In these groves cnidoblasts are present.
From each gastric pouch 3 radial canals will form. The middle one is inter radial canal and the remaining two are ad-radial canals .Inter radial canals will branch, but ad-radial canals will not branch. Thus 4branchedi inter radial canals and unbranched radial canals will open into ring canal or circular canal on the margin of the umbrella.
Between two adjacent gastric pouches one perradial canal is present. It is branched. It is also connected with ring canal.
Circulation of water in the gastro vascular system: By the beating of cilia of the ventral grooves of oral arms, lining of the gastro vascular canals a current of water will circulate through gastro-vascular system in a fixed route.
Through mouth water enters into stomach. From stomach through gastro-Qenital canals water reaches the gastric pouches. Then through ad radial canals this water will reach ring canal. From this ring canal water will come to stomach through hyper radial canals. The water from ring canal will be brought to the ventral grooves of oral arms through inter-radial canals. Thus water circulates in the medusa. To complete one circulation, nearly 20 minutes time is required.
The incoming water brings food into the medusa body. The food of medusa consists of small crustaceans, worms, larval forms etc.,
  1. Ingestion: Cnidoblasts of the oral arms, and gastric filaments will paralyze and entangle the prey.
  2. Digestion: It is carried-on in stomach, and gastric pouches. A part of digestion is carried-on in the stomach by digestive enzymes, it is called extra­cellular digestion. This partly digested food is ingested by nutritive muscle cells of the endoderm and the digestion is completed. It is called intracellular digestion.
  3. Absorption: The digested food is distributed to all parts of the body and is utilized.
  4. Egestion: The undigested food is sent out through the out-going water.

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Last modified on Wednesday, 19 April 2017 02:36

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    The kidneys are made up with numerous uriniferous tubules.kidneys are located in dorsal side of coelom.
    A typical uriniferous tubule having three parts.
    1. Ciliated peritoneal funnel
    2. Malpighian body
    3. Ciliated convoluted tube
    1. Paired kidneys are dark red and irregular in shape. These are flattened organs. 1. Kidneys are dark red and some what rectangular and flattened organs. 1. Kidneys are dark red and bean shaped organs.
    2. Kidneys are located in the posterior region of the abdominal cavity and attached to the dorsal wall by a fold of peritoneum. 2. Kidneys are situated in the anterior part of the abdomen. 2. Kidneys are located in the posterior part of the abdominal cavity.
    3. Right and left kidneys are opposite to each other. 3. Same as in calotes. 3. The two kidneys are distinct. The right kidney lies much ahead than the left kidney.
    4. They are attached to the dorsal muscles. 4. They are fitted in the hollows of the pelvic girdle. 4. Same as in calotes.
    5. They are very near to the median line kidneys are Metanephros type. 5. They are a little away from the median line. Kidneys are Meta nephros type. 5. They are well away from the median line. Kidneys are meta ne phros type.
    6. Each kidney has two lobes Anterior lobe is broad and posterior lobe is broad Hilus is absent. 6. Each kidney has three lobes They are anterior, median and posterior lobes. Hilus is absent. 6. Each kidney is a single-lobed structure. Inner side of the kidney has a concave depression is known as the 'hilus'.
    7. The two kidneys are united posteriorly forming a V-shaped structure. 7. The two kidneys are separate and do not fuse with each other. 7. The two kidneys are distinct.
    8. The two ureters are narrow, thin-walled ducts extending behind from the kidneys to the cloaca, where these open into the urodaeum. 8. Same as in Calotes. 8. The ureters open into the urinary bladder. Ureters arise from the hilus of each kidney.
    9. There is no pelvis. 9. There is no pelvis. 9. Each ureter is expanded in its kidney into a funnel like pelvis.
    10. In males the ureters join at its posterior end with its corresponding vas deferens and both open by a common urino-genital aperture. 10. The ureters do not join with the vas deferens and both open separately into the cloaca. 10. Ureters open separately into the urinary bladder.
    11. A thin walled urinary bladder opens on the ventral side of cloaca. 11. Urinary bladder is absent. 11. Urinary bladder is a large, median, pear, shaped, thin walled transparent sac.
    12. Urinary bladder communicates with urodaeum thrumph its ventral wall. 12. __ 12. Urinary bladder opens into the urethra or unnogenital canal.
    13. Calotes is uricotelic animal Urine consists n.ainly of uric acid. 13. Urine consists mainly of uric acid cotelic animal. 13. Urine consists mainly of urea - ureotelic animal.
    14. Urine is excreted in a semi solid state. 14. Urine is excreted in a semisolid state (Bird droppinos). 14. Urine is passed out in a fluid state.
    Kidneys are the major excretory organs in all vertebrates. Some other organs such as lungs, gills, liver, intestine and skin also remove certain waste materials besides their normal functions. These are also known as the accessory excretory organs. Both shark and frog are anamniotic animals.
    The kidneys lie dorsal to the coelom and are composed of large number of renal or uriniferous tubules. A uriniferous tubule typically con­sists of three regions - a ciliated peritoneal funnel, a malpighian body and a ciliated convoluted tube. The malpighian body is a two layered cup, the 'Bowman's capsule' containing a mass of capillaries the 'glomerulus'. The convoluted tube opens into a Longitudinal duct which extends backwards and opens into the cloaca. The excretory organs remove the nitrogenous waste products formed during the metabolic activities from time to time. If these products are not removed from the body, they are changed to toxic substances.
    1. Paired kidneys are very long and ribbon like. 1. Paired kidneys are short and roughly oval in shape.
    2. Each kidney is differentiated into a small non-renal part (genital part) and a long posterior renal part. The two parts exhibit morphological difference. 2. Each kidney possesses genital as well as renal region. But these are not morphologically differentiat­ed.
    3. The kidneys are uriniferous 'Opisthonephros' but functional Mesonephros. 3. The kidneys are mesonephros.
    4. Some uriniferous tubules retain peritoneal funnel. 4. The peritoneal funnels are absent.
    5. The uriniferous tubules have a specialised urea - absorbing seg­ment. 5. The urea-absorbing segment is absent.
    6. Uriniferous tubules lead into special tubes - the urinary ducts (ureters). These are distinct from wolffian ducts. 6. Uriniferous tubules lead into the wolffian ducts.
    7. Ureters run back ward over the ventral surface of the kidneys. 7. Wolffian ducts leave outer border of kidneys and run backward.
    8. Ureters are independent ducts to carry urine from the kidneys to the Urinogenital sinus'. 8. The ureters serve for the passage of genital elements as well as urine. So they are known as urino-genital ducts.Urino genital sinus is absent.
    9. The urinary bladder is absent. 9. A large bilobed urinary bladder is present. It opens into the cloaca opposite the openings of the ureters.
    10. The urine is hypotonic to blood. 10. The urine is hypertonic to blood.
    11. Scoliodon is an ureotelic animal. The endproduct of nitrogen metabolism is urea. A large Quantity of urea is retained in the body as an adaptation to marine life.Excess of urea is excreted chiefly through its gills. 11. Frog is also ureotelic animal. It excretes urine from the cloaca in the form of urea.
    Calotes is a cold blooded (poikilothermic) and terrestrial garden lizard. Pigeon is a ward blooded bird adapted for aerial mode of life. Rabbit is warm blooded and a herbivorous mammal which is also known as Oryctolagus. The circulation of blood in vertebrates is of closed type(circulation occurs is blood vessels. The blood vessels which collect blood from different parts of the body are called as veins. The walls of veins are thick and possess valves.Thier lumen is wide. They collect deoxygenated blood from different parts of the body and carry to the heart. The veins are formed by means of capillaries in the respective tissues or organs. The deoxygenated blood is received by the sinus venosus or the right auricle. The portal veins are having capillaries at their both ends. The pulmonary veins possess oxygenated blood.
    1. The venous system consists of common pulmonary vein, two precaval and one post caval veins. These collect blood from the various parts of the body. 1. The venous system con­sists of three large veins-teeo precavak and one post caval along with four large pulmonary veins. 1. The venous system con­sists of four distinct divisions. i) System of venae carae ii) Hepatic portal system iii) Pulmonary system iv) Coronary system
    2. The two precaval veins collect blood from the anterior part of the body. Each precaval is formed by the union of the internal and external jugular veins from head and the sub clavian vein from the arm. Transverse jugular vein is absent. Azygous vein is also absent. 2. The two precaval veins collect blood from the anterior part of the body. Each precaval vein is formed by the union of Jugular (head), brachial (arm) and pectoral (Pectoral muscfes) veins. Transverse jugular vessel is present in between the jugular veins. Azygous vein is absent. 2. The two precaval veins collect blood from the anterior part of the body. Each precaval vein is formed by the union of the external jugular vein (head) and subclavian vein (fore limb). The right precaval vein receives the azygous (unpaired) and intercostal veins (intercostal muscles and dorsal wall of theory). Left azygous vein is absent.
    3. The post canal vein joins the posterior angle of the sinus venous. It forms by the union right and left efferent renal veins and brings blood from the posterior side. 3. The post caval vein is formed by the union of two large itac veins a tittle behind the liver. 3. The post caval vein is a large median vein. It stands at the cauda region (icaudal vein) and runs forward and receives blood in its course. The veins which join the posl caval vein are pairec ilio himbars, iliacs gonadial renal, anc hepatic.
    4. The renal portal system collects blood from the posterior side of the body. Caudal vein bifurcates into two pelvic veins which . unite in front and form into the median anterior abdominal vein enters into the liver. Each pelvic vein joined by femoral, sciatic veins of that side. From the pelvic arise the renal portal veins which branch into capillaries in the substance of the kidneys coccygeo-mesenteric vein is absent. 4. Renal portal system is not well developed in pigeon caudal vein bifurcates into right and left renal portal veins (Hypo gastric veins) each of which enters the kidney. The hypogastric vein receives the Internal iliac vein abng with femoral & sciatic veins. At the bifurcation of the caudal vein into the two renal portal veins arise a median 'coccygeome-senteric vein'. It is characteristic of birds. The coccygeo- mesenteric vein joins the hepatic portal vein. 4. Renal portal system is completely absent in Rabbit.
    5. The Hepatic portal vein collects blood from the alimentary canal and enters the liver and breaks upto capillaries. 5. The Hepatic portal vein collects bbod from the alimentary canal and emptied into the liver. From the Ever the blood is carried by the post caval vein through hepatic veins. 5. Same as in pigeon.
    6. Epi gastric vein is absent. 6. Epi gastric vein returns the blood from the mesenteries and joins the hepatic veins. This vein corresponds to the abdominal vein of the frog. 6. Epi gastric vein is absent.
    7. The right and left pulmonary veins bring pure blood from the right and left lungs and united into a common branch. Common pulmonary vein opens into the left auricle. 7. Four large pulmonary veins return blood from the posterior part of the left auricle. 7. A pair of pulmonary veins bring oxygenated blood from the lungs They unite by a common arch and open into the dorsal wall of the left auricle.
    8. The right auricle receives deoxygenated blood through sinus venosus and left auricle possess oxygenated blood. In the partially divided ventricle the blood mixes to some extent. 8. The right side of the heart (right auricle & ventricle) receives de-oxygenated blood and left side folded with (left auricle & ventricle) oxygenated blood. 8. Same as in pigeon. Coronary veins collect deoxygenated blood from the wall of the heart. The coronary sinus opens into the right auricle through an aperture guarded by the Valve of The besius'. The opening is called as the 'formina of the The besius'.

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