Comparison Of Digestive System Of Shark Fish( Scoliodon) With Digestive System Of Frog (Rana -Amphibian)

Scoliodon is an aquatic cartilage fish. Rana is. an amphibian. Scoliodon is a carnivorous and voracious feeder. Rana is also a carnivorous animal. To suit to the feeding habits the alimentary canal and the associated glands are formed. Thus the digestive system consists of alimentary and digestive glands. Usually the alimentary canal has formed with mouth, buccal cavity, pharynx, esophagus, stomach, intestine, rectum and cloaca in both these animals. The most important digestive glands are liver and pancreas along with gastric, intestinal glands. The secretions of the digestive glands act upon the food and convert them into their respective end prod­ucts.


Shark Digestive system


Frog-Digestive system

1. The alimentary canal is long and coiled tube divisible into, mouth,buccal buccal cavity, pharynx,oesophagus, stomnch, intestine, rectum and cloeca.   1. Same structures are present.
2. The mouth is ventral, half-moon shaped aperture situated a little behind the anterior end.   2. The mouth is a terminal aperture
3. The upper and lower Jaws are provided with several rows of sharp pointed teeth.   3. The upper jaw alone bears small sharp pointed teeth arranged in a single row. The teeth are absent in the-lower jaw(edentulous)
4. The teeth are large and inwardly curved. The teeth can be replaced many times and are polyphyodont.   4. The teeth are minute and downwardly directed. Vomerine teeth also present.
5. The tongue is small, non-muscular and non-retractile, nonglandular. The posterior end is attached to the floor of buccal cavity and the anterior end is free.   5. The tongue is large, highly muscular, retractile and slimy. The anterior end is attached to the floor of th«buccal cavity and the posterior enc
6. The tongue doesnt help in capturing the food but helps in swallowing the food.   6. The tongue helps in capturing theprey.
7. The side walls of the pharynx areperforated by 5 pairs of gill-slits.   7. The walls of the pharynx are complete.
8. A pair of spiracular openings are also present.   8. Absent.
9. The mucous membrane of the pharynx is rough.   9. The mucous membrane lining the pharynx is smooth and slimy.
10. Glottis is absent.   10. Glottis or the opening oil laryngotracheal chamber is present in the buccal cavity.
11. The stomach is J-shaped and is differentiated into cardiac & pyloric regions.   11 The stomach is not J- shaped but slightly curved sac. it is also differentiated into cardiac & pyloric regions.
12. At the junction of cardiac and pyloric parts there is a smaU blind sac-like outgrowth.   12. No such structure is present.
13. Cardiac valve is present in between the cardiac stomach & pyloric stomach.   13. Absent.
14. At the distal end of the pyloric stomach pyloric valve is present.   14. Pyloric sphincter is present.
15. The pyloric stomach leads into a thick walled muscular chamber-Bursa entiana.   15. Absent.
16. Intestine is comparatively a short tube and it is not differentiated into duodenum and ileum.   16. The intestine is long and coiled tube differented into duodenum (U-shape attain with stomach) andnarrow & long ileum.
17. Intestine possess a spiral valves (Scroll valve)   17. Intestinal wall is produced internally into villi but the scroll valve is absent.
18. The rectal gland opens into the rectum.   18. It is absent.
19. Rectum opens into the cloaca   19. Same.
20. The glands associated with the alimentary canal are liver, pancreas, spleen and rectal gland.   20 The glands associated with the alimentary canal are liver, pancreas and spleen