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COMPARATIVE ANATOMY: EXCRETORY SYSTEM OF REPTILE, BIRD AND MAMMAL

Published in Zoology
Saturday, 15 July 2017 10:21
Lizard, bird and rabbit all these three animals come under the group amniota. The taking away of nitrogenous un wanted waste products from the body is called excretion. If excretion takes place not  properly in the body they become poisonous. Vertebrates main excretory organs are called as kidneys. Skin, gills, lungs, liver and intestine are also acts as accessory excretory organs.
 
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
 
EXCRETORY SYSTEM - GARDEN LIZARD EXCRETORY SYSTEM - PIGEON EXCRETORY SYSTEM - RABBIT
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.

COMPARATIVE ANATOMY: EXCRETORY SYSTEM OF FROG AND FISH

Published in Zoology
Saturday, 15 July 2017 09:56
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.
 
EXCRETORY SYSTEM OF FISH EXCRETORY SYSTEM OF FROG
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.

COMPARATIVE ANATOMY: VENOUS SYSTEM OF REPTILE, BIRD AND MAMMAL

Published in Zoology
Friday, 14 July 2017 22:49
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.
 
VENOUS SYSTEM OF CALOTES (GARDEN LIZARD) VENOUS SYSTEM OF COLUMBA (PIGEON) VENOUS SYSTEM OF ORYCTOLAGUS (RABBIT)
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'.

COMPARATIVE ANATOMY: VENOUS SYSTEM OF FROG AND FISH

Published in Zoology
Friday, 14 July 2017 21:54
Scoliodon commonly called as shark fish is a poikilothermic (cold blooded) animal. It is cartilaginous fish. Rana (frog) is also poikilothermic and amphibious animal. The circulation of blood in vertebrates is of closed type. The blood vessels which collect blood from various parts of the body are known as veins. The walls of the veins are thin and possess valves. Their 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 first enter into the sinus venosus which is the part of the heart. The portal veins are having capillaries at their both ends. The pulmonary veins possess oxygenated blood.
 
 
FISH (SHARK) - VENOUS SYSTEM FROG (RANA) - VENOUS SYSTEM
1. The venous system comprises a system of large thin walled sinuses which collect blood from the different body organs 1. The venous system comprises of thin walled tubular veins.
2. It consists of the following systems i) Anterior cardinal system ii) Posterior cardinal system iii) Hepatic porta! system iv) Ventral veins vi) Cutanecious system 2. It is divided into i) Anterior system of veins ii) Posterior system of veins iii) Portal systems.
3. The anterior cardinal system and the interior jugular sinuses collect blood from the head region through a number of sinuses. 3. The blood from the head region is collected by a pair of precoval veins. Each precaval vein is formed by External jugular, innominate and subclavian veins.
4. The blood from gills is collected by five pairs of dorsal nutrient sinuses and five pairs of ventral nutrient sinuses. 4.The blood from the lungs is collected by a pair of pulmonary veins.
5. The nutrient sinuses carry deoxygenated blood. 5. The pulmonary veins carry oxygenated blood.
6. The nutrient sinuses empty into anterior cardinal and interior jugular sinuses which inturn open into the ductus cuvieri. Thus the blood finally carried to the sinus venosus. 6. The pulmonary veins open into the left auricle.
7. From the posterior part of the body the blood is collected by i) a pair of posterior cardinal sinuses ii) a pair of lateral abdominal veins iii) a pair of brachial veins. 7. The blood from the posterior part of the body is collected by i) renal portal system and ii) Post caval vein.
8. The renal portal system includes the caudal vein and the renal postal veins & Iliac veins. The blood from the pelvic fins is not carried to the kidneys. 8. The renal portal system consists of veins hind limbs i.e. femoral, sciatic and renal portal veins. The caudal vein is absent.
9. It is absent. 9. A part of the blood from the hind-body is transported to the liyer by an anterior abdominal vein.
10. The blood from the kidneys is collected by renal veins which open into posterior cardinals, opening into the cuvierian sinus. 10. The blood from kidneys is collected by four pairs of renal veins which open into the post caval vein.
11. The brachial veins join the lateral abdominals to form sub clavian veins which open into the ductus cuvieri. 11. The brachial veins open into the precaval veins particularly into the subclavian veins.
12. Three pairs cutaneous veins collect blood from the muscles of skin and open into the cardinal sinuses, lateral abdominals and brachial veins. 12. The cutaneous veins are only one pair which join with muscular & brachial and finally open into the subclavian veins.
13. The venus blood does not enter the sinus venosus directly. But it is collected first by the cuvierian sinus present transversely. 13. The blood collected by the two precavals and one post caval veins directly enters into the sinus venosus.
14. The blood from the parts of the alimentary canal is collected by the Hepatic portal vein and empties into the liver and from there it is transported by Hepatic sinuses into the sinus venosus. 14. The Hepatic portal vein collects blood from the different parts of the alimentary canal and empties into the liver. From the blood is transported into the sinus venosus through the hepatic veins and post caval vein.

COMPARATIVE ANATOMY: ARTERIAL SYSTEM OF REPTILE, BIRD AND MAMMAL

Published in Zoology
Friday, 14 July 2017 19:56
Calotes is  called as garden lizard. It is a poikilothermic terrestrial reptile. Columba is commonly called as pigeon, being a bird it is  adapted for aerial mode of life. Oryctolagus (rabbit) is an herbivorous mammal. The blood circulation in these vertebrates is of closed type. The blood vessels which carry blood from the heart to the various parts of the body are known as arteries The walls of the arteries are thick and do not possess valves. The pure blood flows in the arteries. However the arteries which carry blood from the heart to the respiratory organs possess deoxygenated blood. The blood has high pressure in the arteries. Arteries ends by means of blood capillaries in the tissues. The different arteries associated in the circulation of blood form a system which is called as Arterial System.
 
In the above three vertebrates, the arteries arise differently but carry blood from the heart to the various parts of the body.
 
 
Calotes (Garden Lizard) Columba (Pigeon) Oryctolagus (Rabbit)
1. Arterial system consists of a pair of systemic arches and a pulmonary arch. 1. Arterial system consists of two arches-Right sys­temic arch and pulmonary arch. The right systemic arch is called Right Aortic arch. 1. Aiterial system con­sists of two arches, left systemic arch and pulmonary arch. The left systemic arch is known as Left aortic arch
2. The systemic arches and the pulmonary arch arise from the dorsal and ventral parts of the single ventricle. All the three arches are connected by connective tissue. 2. Right aortic arch arises from the left ventricle and pulmonary arch arises from the right ventricle. 2. Left aortic arch airses from the left ventricle and the pulmonary arch arises from the right ventricle.
3. The carotid branch of each side is connected with systemic arch by a vessel, 'Ductus caroticus'. 3. Ductus caroticus is absent. 3. Same is absent.
4. The subclavian arteries arise from the right systemic arch. 4.The right & left carotid and sub clavian arteries originate from the respective innominate arteries, ises. 4. The right carotid and sub clavian arteries arise from the innominate artery. But the left carotid and sub calvian arteries originate directly from the right aortic arch
5. Inter cestal arteries are present. 5. Same are present. 5. Same are present.
6. It is absent. 6. Pectoral artery supplies blood to the muscles of the wings. 6. It is absent.
7. Coeliac artery and anterior mesenteric artery arise separately from the dorsal from the dorsal aorta. 7. Same in pigeon. 7. Same in rabbit.
8. It is absent. 8. It is absent. 8. Phronic artery supplies blood to the muscles of the Diaphragm.
9. A pair of gonadial arteries are present. 9. From the anterior renal arteries the gonadial arteries are formed. 9. Paired Gonadial arteries arise directly from the dorsal arch.
10. Unpaired posterior mesenteric artery is present. 10. Same is present in pigeon. 10. Same is present in rabbit.
11. Three pairs of renal arteries arise from the dorsal aorta. 11. The anterior renal arteries develop from the dorsal aorta. But middle & posterior renal arteries arise from the sciatic artery of each side. 11. A pair of renal arteries arise from the dorsal aorta.
12. Common Iliac ar­teries are formed from the dorsal aor­ta. 12. The internal iliac arteries are formed from the dorsal aorta. 12. Iliolumbar arteries arise from the dorsal aorta.
13. The caudal artery is the terminal portion of the dorsal aorta to the tail. 13. The caudal artery the terminal portion of the dorsal aorta to the tail. 13. The caudal artery is the continuation of the dorsal aorta to the tail.
14. The pulmonary arteries carry blood from right part of the single ventricle to theright and left lungs. 14. Each pulmonary artery carries deoxygenated blood to the respective lung for purification. 14. The pulmonary artery which arises from the right ventricle divides into two branches and carry deoxygenated blood to the respective lungs.
15. Coronary arteries supply blood to the walls of the heart. 15. Coronary arteries supply blood to the walls of the heart of bird. 15. Coronary arteries supply blood to the walls of the heart.

COMPARATIVE ANATOMY: ARTERIAL SYSTEM OF FISH (SCOLIODON) AND FROG (RANA)

Published in Zoology
Friday, 14 July 2017 18:30
Scoliodon ( Shark) is a poikilothermic animal. It is a cartilaginous fish. Frog ( Rana) is a cold blooded and amphibious animal. The circulation of blood is carried by closed vessels. The vessels which supply blood to the various organs of the body are known as arteries as the net work of arteries form the Arterial system. The walls of arteries are thick and lumen is narrow. The blood pressure is high in the arteries. Arteries do not possess valves. The arteries end in capillaries. Arteries deeply seated in the body. Mostly arteries contain oxygenated blood. A few arteries also carry deoxygenated blood to the respiratory organs (either gills or lungs) for purification.
 
 
Scoliodon (Fish) Rana (Frog)
1. The arterial system consists of a ventral aorta, afferent and efferent branchials, dorsal aorta, and its branches and hypobranchials. 1. The arterial system consists of a truncus arteriosus, three pairs of aortic arches and the dorsal aorta & its branches.
2. Five pairs afferent branchial arteries are present. 2. Absent.
3. Efferent branchial system is associated with gill-slits along with the respective arteries. 3. Absent.
4. The arteries to the head are given off from the first pair of epibranchials and by the branches of dorsal aorta carotid labyrinth is absent. 4.The head is supplied blood by the branches. Carotid arteries arising from the truncus arteriosus. Carotid labyrinth is present.
5. Parietal arteries are present. 5. Parietal arteries are absent.
6. Hypobranchial plexus is present. 6. It is absent.
7. Dorsal aorta is formed by the union of epibranchial arteries of both the right and left sides. 7. The second branches of turncus, the systemic arches of the left and right sides unite to form the dorsal aorta.
8. Subclavian arteries arise from the dorsal aorta. 8. Sub clavian artery arises from each systemic arch.
9. Absent. 9. Occipito-vertebral artery arises from the systemic arch of each side.
10. Coeliaco-mesenteric artery aris­es from behind the union of the four pairs of epibranchials. 10. Coeliaco-mesenteric artery arises from the junction of the two system¬ic arches.
11. Just below the Coeliaco-mesen­teric artery, lienogastric artery arises. 11. Lie no gastric artery is absent.
12. The parietal artery gives off four pairs renal arteries. 12. Four pairs of renal arteries arise directly from the dorsal aorta.
13. Gonadial (Spermatic or ovari­an) artery arises from the lieno ­gastric artery. 13. Gonadial arteries arise directly from the first pair of renal arteries.
14. Dorsal aorta terminates into caudal artery. 14. C-iudal artery is absent.
15. Pulmo cutaneous arch is absent. 15. The third branch of truncus is the pulmo-cutaneous arch which is divided into pulmonary and cutanecious arteries.
 
The heart of fish possess venous blood and blood passes through the heart only once in a complete circuit. But in frog the heart receives both oxygenated and venous blood and the circulation is bi circuit.
 
The fish is an aquatic animal and possesses five pairs of gills. The blood is supplied by pairs of afferent bronchial arteries and is collected by nine pairs of efferent bronchial arteries. In frog however, the respiratory organs are a pair of lungs (skin & buccal cavity also help in respiration) which are supplied by a pair of pulmonary arteries.

COMPARATIVE ANATOMY: HEART STRUCTURE OF REPTILE, BIRD AND MAMMAL

Published in Zoology
Thursday, 13 July 2017 20:25
Calotes is a poikilothermic terrestrial lizard. Columba is pigeon adapted for aerial mode of life. Oryctolagus is an herbivorous mammal.
 
Both pigeon and Rabbit are warm blooded animals. Heart, arteries, veins and blood capillaries are included in the circulatory system. The blood circulation is controlled by an important organ Heart. Normally the blood flows in the closed vessels. So blood circulation is of closed type in verte­brates. The heart possesses auricles and ventricles. The pericardium is at­tached to the heart by gubernaculum cordis'.
 
The number of chambers of heart varies from calotes and other two vertebrates (Pigeon & Rabbit). The heart contracts and relaxes rhythmi­cally. This is called heart beat.
 
The detailed comparison of the heart of the above three animals is mentioned below.
 
Calotes (Lizard) Columba (Pigeon) Oryctolagus (Rabbit)
1. Heart is situated mid ventrally in the an­terior part of the body cavity in the pleuro peritoneal cavity be­hind the sternum. 1. Same way the heart is located. 1. Heart is situated in the thoracic cavity, between the lungs of two sides (Mediastinum). It is present slightly towards the left side.
2. Heart is comparatively smaller in size. 2. Heart is comparatively larger in size. 2. Heart is comparatively larger in size.
3. It is enclosed by double walled pericardium. 3. It is also enclosed in the double walled pericardium. 3. Same.
4. Heart includes a dorsal sinusvenusus aright auricle, a left auricle and a single incom-pletely divided ventricle. 4. Heart is four chambered, sinus venosus is absent in the adult. Completed divided two auricles and two ventricles by inter auricular septum and inter ventricular septum respectively. 4. Same as in columba.
5. The three vena cavae or two precavals and a post caval vein open into the sinus venosus. 5. The three vena cavae or two precavals and a post caval empty the blood directly into the right auricle. 5. Same as in pigeon.
6. The left auricle receives two pulmonary veins from the lungs. 6. The left auricle receives four pulmonary veins from the lungs. 6. Left auricle receives two pulmonary veins from the lungs.
7. The right auricle pos­sess sinu auricular aperture guarded by valve. 7. Absent. 7. Absent.
8. The two auricles are completely separated by inter auricular sep­tum. But the inter ven­tricular septum in the ventricle is incomplete. Hence oxygenated and deoxygenated types of blood is mixed to some extent in the ventricle. 8. Complete inter auricular and inter ventricular septa are present. There is no possibility of mixing the oxygenated blood with deoxygenated blood. 8. Same as in pigeon.
9. The heart of lizard is in a transitional stage approcarhing the double circuit stage But it has not reached it completely due to incomplete division of the encircle. 9. The heart is a double circuit heart because of complete division of ventricle into right and left chambers. 9. Same as in pigeon.
10. The auriculo ventricular aperture is guarded by two flap like semilumar valves. 10. The right auriculo ventricular aperture is guarded by two large muscular flap like valve and the left by three valves. 10. The right auriculo-uentricular aperture is guarded by tricuspid valve and the left by bicuspid valve (mytral valve).

11. There are three aortic arches arising from the ventricle.

  1. Pulmonary trunk (ventral most)
  2. Right systemic trunk (arise from left side of ventricle)

11. Only two aortic arches originate from the ventricles.

  1. Pulmonary trunk (from right ventricle)
  2. Right systemic trunk (from left ventricle)

i.e. Right aortic arch is characteristic of birds.

11. Only two aortic arches arise from the ventricles.

  1. Pulmonary arch (right ventricle)
  2. Left systemic aorta (Left aortic arch from the left ventricle). Right aortic arch is absent.
12. Ductus caroticus is present (connection between carotid & systemic arches) 12. Absent 12. Absent
13. Lizard's heart presents a transitional heart, since it approaches the double circuit heart but has not yet completely attained. So the heart is less efficient. 13. Avian heart has at tained maximum com olexity and is a double circuit heart, i.e. venous blood is com pletely separated frorr oxygenated blood. 13. Same as in Pigeon.
14. Absent. 14. Sinu-Auricular Node and Auriculo ventricular node are present. 14. SA - node and A.V. node are present. In addition bundle of His muscles are also develop.

COMPARATIVE ANATOMY: HEART STRUCTURE OF FROG AND FISH

Published in Zoology
Thursday, 13 July 2017 19:29
Scoliodon is a poikilothermc and cartilagenous fish. Rana is also poikilothermic and amphibious animal. In the circulatory system the heart is the most important organ. The blood vascular system in the vertebrates is of closed type. The heart lies in the pericardial cavity of the coelom. It is on the ventral side of the alimentary canal and present anteriorly. In scoliodon the heart is two chambered where as in Rana it is three chambered.
 
Heart is a pumping organ of blood. From various parts of the body it collect blood mainly through veins and supplies blood through arteries.
 
Normally the heart is enclosed by a double walled pericardium which possess pericar­dial fluid. The heart contracts and relaxes rhythmically which facilitate the circulation of blood.
 
FISH HEART (SCOLIODON) FROG HEART (RANA)
1. Heart is approximately pear-shaped. 1. Heart is approximately pear-shaped.
2. The pericardial cavity is not wide and the pericardium forms double membrane around the heart. 2. The pericardial cavity is not wide and the pericardium forms double membrane around the heart.
3. The heart is formed of a dorsally placed sinus venosus and ventrally placed two auricle, a ventricle and truncus arteriosus or conus arteriosus. 3. The heart is formed of a dorsally placed sinus venosus and ventrally placed two auricle, a ventricle and truncus arteriosus or conus arteriosus.
4. The atrium or auricle is two-chambered and lies anterior to the ventricle. Auricles are separated by Inter auricular septum. 4. The atrium or auricle is two-chambered and lies anterior to the ventricle. Auricles are separated by Inter auricular septum.
5. The auriculo-ventricular valve is membranous. 5. The auriculo-ventricular valve is membranous.
6. The conus arteiiosus is incompletely divided by the spiral valve laterally into cavurn aorticum leading to carotid and systemic arches and the cavum pulmocutaneum leading to the pulmocutaneous arch. 6. The conus arteiiosus is incompletely divided by the spiral valve laterally into cavurn aorticum leading to carotid and systemic arches and the cavum pulmocutaneum leading to the pulmocutaneous arch.
7. The opening of the truncus with valves are arrenged in two transvarse rows. 7. The opening of the truncus with the ventricle is guarded by three semilunar valves arranged in a single row. They devide rruncus into a proximal pylangium and a distal synangium.
8. The walls of the auricle are thick. 8. The muscular walls of the auricle are thin.
9. The walls of the ventricle are highly muscular. 9. Same type of ventricle is present.
10. The lips of the bilaminate valves are connected to the inner surface of the ventricle is prominent part of the heart. 10. The membranous valves are connected to the inner surface of the ventricle by chordae-tendinae. Both auricles and ventricle are essential parts of the heart.
11. The fish heart is venous or branchial heart because it receives deoxygenated blood only. 11. The frog's heart receives both oxygenated and deoxygenated blood. The deoxygenated blood remain separate in the auricles but get mixed in the ventricle.
12. Blood passes only once through the heart in a complete circuit. 12. Blood passes through the heart twice in a complete circuit.
13. Such type of arrangement is absent. 13. The sinus venosus opens into the right auricle through simi-auricular aperture guarded by simi auricular valve which is also known as pace maker.
14. No separate vessel collects oxygenated blood since the heart is venous heart 14. The oxygenated blood is collected by pulmonary vein from lungs and carries into left auricle.

COMPARATIVE ANATOMY: HIND LIMBS SKELETON IN REPTILE, BIRD AND MAMMAL

Published in Zoology
Wednesday, 12 July 2017 20:27
The Appendicular skeleton is one of the divisions of the endo skeleton. It includes the pectoral and pelvic girdles and limb bones. The skeleton of the limb in all the tetrapods shows a similar fundamental and structural similarity. However the differences such as arms, legs, wings and paddles are seen in the respective animals. A few tetrapods have completely lost one or both pairs of appendages. The limbs are totally absent in caecilians, most snakes and snake-like lizards.The Appendicular skeleton is one of the divisions of the endo skeleton. It includes the pectoral and pelvic girdles and limb bones. The skeleton of the limb in all the tetrapods shows a similar fundamental and structural similarity. However the differences such as arms, legs, wings and paddles are seen in the respective animals. A few tetrapods have completely lost one or both pairs of appendages. The limbs are totally absent in caecilians, most snakes and snake-like lizards.

The typical tetrapod hind limb can be divided into three seg­ments. The thigh, shank and foot (pes) are the three segments. If there are five toes, normally this type of limb is known as pent dactyl limb.
 
The skeletal structures of the hind-limb consists of femur, tibia, fibula, tarsals, metatarsals and phalanges.

The femur is the bone of the high and its head articulates with the acetabulum. Its distal end articulates with fibula. The tibia and fibula are the bones of the shank region. They articulate with femur proximally and distally with the tarsal’s of the ankle bones. The fibula bears the most of the body weight.

The foot can be divided into ankle, instep and toes. The ankle is supported by tarsals, which are arranged in rows. The skeleton of ankle or tarsus is the most stable of the regions of the ankle. The instep or metatarsus is supported by the metatarsals. These are elongated bones. The metatar­sals are followed by linear series of phalanges of the toes. The phalanges number varies from 1 to 5.

The first toe of the hind limb is called 'hallux or great toe' and the fifth toe is the 'minimus'.
 
Calotes (Garden Lizard) Columba (Pigeon) Oryctolagus (Rabbit)
1. The bones of the hind limb are femur, Tibia, fibula, tarsals, metatarsals and phalanges. 1. The bones of the hind limb are femur, tibia, fibula, tibiotarsus, tarsometatarsals and phalanges. 1. The bones of the hind limb are femur, tibia fibula tarsals, meta tarsals and phalanges.
2. The femur is stout bone of the thigh region. It has long, slender and curved shaft in the middle. The shaft enlarges at both the ends. 2. The femur is a stout bone of the thigh region. It has a long, curved shaft in the middle. The shaft has broad ends. 2. Femur consists of long, stout curved shaft. The femur gives support to the thigh region.
3. The proximal end of the shaft bears a rounded smooth head which fits info the acetabulum. There are also distinct prominences lesser trochanter and greater trochanter near the head. 3. The proximal end of femur is produced into a rounded head for the articulation with the acetabulum. Opposite to the head a small protuberance greater trochanter is present. 3. The proximal end of femur bears a rounded knob-like head which fits into the acetabulum. There are three rough projections greater, lesser and third trochanters present near the head. Lesser trochanter lies behind the head, greater trochanter in the middle line and the third trochanter opposite to the head are seen.
4. It is absent. 4. There is an articular surface is present between the head and trochanter for the antitrochanter of ilium. 4. It is absent.
5. Two knob-like condyles are present at the distal end of thefemur. These articulate with the tibia of the shank. Intercondylar groove is present between the two condyles. Patella is absent. 5. The distal end of femu has two prominent condyls with a intercondylar groove. Patella slides in the intercondylar groove on the anterior side. It is a disc-like sesmoid bone. 5. The distal end of femur is pulley-like having two condylesfor tibio-fibule which are separated by a patellar groove. A large sesmoid bone called the patella slides in the patellar groove. It is attached to the tibia by a ligament. Patella is present at the knee-joint.
6. The shank consists of two long bones - the tibia and the fibula. They are separate bones. 6. Tibiotarsus fibula is formed of tibiotarsus and fibula. They are separate bones. 6. Tibiofibula is formed of tibia and fibula. They are separate bones.
7. Tibia is a stout and curved bone present on the inner side. Its proximal end bears two concave facets for the articulation with the femur. It has also a longitudinal ridge the cnemial crest on the side. Tibiotarsus is absent. 7. Tibiotarsus is a large straight and stout bone and also longer than fibula. It is formed by the fusion of tibia and proximal row of tarsals. The proximal end of it bears a pair of articular surfaces for the condyles of the femur and in between them the cnemial crest for the attachment of tendon of extensor muscles. 7. Tibia is stouter towards the anterior end and narrow towards the posterior end. Its proximal end bears two concave facets for the articulation with the femur and distinct cnemial crest on side.
8. Tibia distally bears a concavity for the tarsals. 8. Tibio tarsus distally bears a pulley-like articular surface for the tarsals which is surrounded by a pair of distal lateral tubercles. 8. Tibia distally bears articular surface for the tarsals.
9. Fibula is a slender bone present on the outerside. It bears facets on either side. 9. Fibula is small, slender bone. It is closely applied to the tibiotarsus. 9. Fibula is a slender and weak bone. It lies on the outer side. The bone is narrower towards the distal end and is closely applied to the tibia.
10. Tarsab are five in number which are arranged in two rows. Proximal row has two tarsals the larger compound piece formed by the fusion of a rjbiale, intermedium and centrale and present infront of tibia. A small fibulare present infront of the Sbula. The distal row has three small tarsab called distal tarsab or distalia. 10. The free tarsals are absent. The proximal row of tarsals are fused with tibia and forms tibiotarsus. The distal row of tarsals are fused with the metatarsals and forms tarso metatarsus. It is as long as the femur bone. It is straight and stout. 10. There are six tarsal bones which are arranged in two rows. The proximal row tarsab are two, astragalus and calcaneum. Astragalus is considered to represent two fused tarsals. Calcaneun is produced back wards into a strong calcaneal process which forms the heel. The central row has only one tarsal-centrale or navicular. The distal row contains three tarsab. The first distal tarsal is absent due to the absence of hallux. The second distal tarsal is mesocuneiform which is the smallest distal tarsal. The third distal tarsal is ecto cuneiform which largest one. The fifth distal tarsals are fused to form largest bone in the row - cuboid.
11. There are five meta-tarsals corresponding to the five toes. 11. There are four meta tarsals. The first one is free and in the form of a small projection. The second, third and fourth are fused with the distal row of tarsals to form tarso metatar­sus. Ankle joint is known as mesotarsal. 11. There are four meta tarsals. There are second, third, fourth and fifth, meta tarsals. The first one is absent
12. There are five toes. There are two pha­langes in the hallux, three in the second, four in the third, five in the fourth and three in fifth toes. The pha­langes formula can be expressed as 2, 3, 4, 5, 3 (same as for the hand). The terminal phalanx of each toe supports a strong, curved, horny & pointed claw. 12. There are four toes. The hallux is directed backwards and contain two phalanges. The second toe with three, third one with four and the fourth one with five phalanges are formed. The phalanges formulae can be ex¬pressed 2, 3, 4, 5. The terminal phalanx of each toe is pointed and curved which supports a strong, pointed horny claw. 12. There are four toes. Each toe has three phalanges. The phalanges for­mula can be ex­pressed as 3, 3, 3, 3. The terminal part of each phalanx is pointed and curved to support a horny claw.

COMPARATIVE ANATOMY: SKELETON OF THE FORE LIMBS IN LIZARD, BIRD AND MAMMAL

Published in Zoology
Wednesday, 12 July 2017 19:25
The Appendicular skeleton is one of the divisions of the endo skeleton. It includes the pelvic and pectoral  girdles and limb bones. The skeleton of the limb in all the tetra pods shows a fundamental and structural similarity. However, the differences such as arms, legs, wings and paddles are seen in the respective animals. A few tetra pods have completely lost one or both pairs of appendages. The limbs are totally absent in caecilians, most snakes and snake-like lizards. In sirens, the lizard-chirotes, manatees and dugongs only fore-limbs are present. The Appendicular skeleton is one of the divisions of the endo skeleton. It includes the pelvic and pectoral  girdles and limb bones. The skeleton of the limb in all the tetra pods shows a fundamental and structural similarity. However, the differences such as arms, legs, wings and paddles are seen in the respective animals. A few tetra pods have completely lost one or both pairs of appendages. The limbs are totally absent in caecilians, most snakes and snake-like lizards. In sirens, the lizard-chirotes, manatees and dugongs only fore-limbs are present.

A typical tetrapod fore limb can be divided into three segments. The upper arm, fore arm and hand (menus) are the three segments. As there are five fingers normally, this type of limb is known as pentadactyl limb.
The skeletal structures of the fore limb consists of humerus, radius ulna, carpals, Meta carpals and phalanges.

The humerus is the bone of the upper arm and its head articulates with the glenoid cavity .Its distal end articulates with the ulna The Radius and ulna are the bones of the fore arm. They articulate with humerus proximally and distally with the carpals of the mist bones. The radius bears most of the body weight.

The hand can be divided into wrist, palm and digits (fingers). The wrist is supported by carpal bones which are arranged in rows. The palm is supported by the metacarpals. The metacarpals are followed by linear series of phalanges of the fingers The phalanges number vary from 1 to 5.

The first finger of the fore limb is called 'pollex or thumb' and the fifth finger is the 'minimus'.
 
Calotes (Garden Lizard) Columba (Pigeon) Oryctolagus (Rabbit)
1. The bones of the fore limbs are humerus, radius, ulna, carpals, metacarpals and phalanges. 1. The bones of the fore limb are humerus, radius, ulna, carpals carpometa carpus and phalanges. 1. The bones of the fore limb are humerus, radius, ulna, carpals, metacarpals and phalanges.
2. Humerus is in the form of a long bone with proximal and distal ends. 2. Humerus is a long & slightly flattened with a bent shaft associated by proximal and distal ends. 2. Humerus possess a proximal head, shaft and a distal end.
3. The proximal end of humerus is round and distal end is pulley like with two articular surfaces for the radius and ulna. Supra trochlear foramen is absent. 3. The proximal end of humerus is highly expanded and form into the head A prominent deitcid ridge and a pneumatic foramen are present near the head. The distal end articulates with the radius and ulna by the articular surfaces. Supra trochlear foramen is absent. 3 The proximal end of hu-merus is divided into two parts by a bicipital groove. One part has head which fits into the glenoid cavity. This part has lesser tuberosity. The greater tuberosity is present on the other part. Shaft is present along with deltoid ridge. The distal end has median and lat¬eral epicondyles. Pulley-like trochlea is formed at the distal end which articulates with ulna. Suprotrochlear foramen is present.
4. Two elongated and separate radius and ulna bones are present. 4. Same as in calotes. 4. Same as in columba.
5. Radius is a slender bone. It has a styloid process and concavity for the carpalsdistally. 5. Radius is a straight and slender bone. It has a concavity for the articulation with humerus at the proxima end The distal end is convex. 5. Radius is small slen­der and slightly curved bone With a concavity at the proximal end. The distal end is flat.
6 Ulna is rod liket and stoutet than radius, Proximally it has ole cranon process to articulate with humerus. Distally it has a concavity for the articulation with carpals. 6. Ulna is stouter and longer than radius It is slightly curved. A cranon process to blunt olecranon process is present at the proximal end. The distal ends of radius & ulna articulate with carpometacarpus. 6. Ulna is a long and curved bone. Proximally it bears olecranon process and sigmoid notch for the articulation with the trochlear end of humerus. Epiphyses are present at the distal ends of radius & ulna for the articulation with carpals.
7. Wrist or carpus has ten (10) small bony carpals arranged in three rows. The proximal row has three carpals - radiale, intermedium and ulnare. A centrale lies in the second row. A pisi­form is attached to the distal end of the ulna on its post axi­al side as an addi­tional bone. The third row has five distal carpals. Ex­cept the fourth, the remaining distal carpals are very small. 7. The wrist contains only two proximal carpals. One smaller-radiate and a larger ulnare articulate with radius & ulna respec­tively. The three dis­tal carpals are fused with the meta carpa­ls to form the carpometa carpus. It is a characteristic feature of aves. 7. Wrist consists of eight small carpal bones arranged in two rows. The proximal row contains three carpals-radiale or scaphoid, intermedium or semilunar and ulnare or unciform. The median row has a single centrale. The distal row comprises four true carpals-trapezium, trapezoid, smallest magnum and largest unciform.
8. Carpometa carpus is absent Five slen­der meta carpals support the palm. These are of unequal size & with expanded ends. The middle or third meta carpal is the longest, the second and fourth are only a little shorter than the third. The first and fifth meta carpals are much shorter. 8. Meta carpals are three in number which are fused with the distal carpals and form an elongated compound bone carpometa carpus. 8. There are five long, slender and of unequal size metacarpals support the palm. The first is the shortest and the third is the longest. Each meta carpal has small epiphysis at their end with a middle slender shaft. Carpometa carpus is absent.
9. There are five fingers. 9. There are three fingers. 3. There are five fin­gers.
10. The phalanges are the small bones sup­port the fingers. The number of phalanges differ in the respec­tive fingers. The first finger has two, sec­ond has three, third has four, fourth has five and fifth has three phalanges Thus the phalanges formula can be ex­pressed as 2,3, 4, 5, 3. 10. The phalanges are the small bones sup­port the fingers. The first finger has one, second has two and third has one phalan­ges. Thus the phalan­ges formula can be expressed as 1, 2, 1.There are no claws on the fingers. 10. The phalanges are small bones and their total number is 14. The first finger has two phalanges & the remaining four fingers have three phalanges each. Thus the phalanges formula can be expressed as 2,3,3,3.3.
11. Sesamoid bones are absent. The distai phalanx of each finger supports a strong curved, pointed claw is formed from the epidermis. 11. Sesamoid bones are absent. 11. Sroas nodule-like bones are present on the underside of the fingers. These are seen at the joints between the meta carpals and the first phalanges and also between the second and third phalanges. These provide additional strength to the fingers during burrowing.
12. It is a penta dactyl limb. 12. The fore limb supports the wing. 12. it is a penta dactyl limb.
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