Frog : Alimentary Canal

Question 1

Alimentary Canal :

Answer 1

Alimentary canal is a long tubular structure extending from end to end of the body. It begins from mouth to cloacal aperture.

Question 2

The parts of Alimentary canal are:

Answer 2

1) Mouth
2) Buccopharyngeal cavity
3) Oesophagus
4) Stomach
5) Small intestine
6) Large intestine

Question 3

1) Mouth :

Answer 3

It is a wide slit like aperture at the anterior end of the snout. It extends from tympanum of one side to that of other side. Mouth is bounded by two jaws, upper movable and lower non-movable.

Question 4

2) Buccal Cavity(I) :

Answer 4

Wide but shallow cavity containing mucus secreting cells. The secretion keeps the buccal cavity moist and helps to lubricate food on swallowing.
- Structures associated with upper jaw :
- On the roof of buccal cavity there are internal which communicate through nasal chamber with external nares.
- Bulging of eyeballs to push the prey inward
- Near the conjunction of two jaws, are eustachian openings on each side through which it communicated with the middle ear of same side.

Question 5

2) Buccopharyngeal cavity (II) :

Answer 5

• Contains two cavity called gullet and glottis.
  -Upper jaw bears maxillary teeth attached to jawbone which is of homodont , acrodont and polyphyodont and vomerine teeth on the roof of buccal cavity.
• Teeth of frog doesn’t involve in mastication.
• Tongue is attached to the anterior margin of buccal floor.
• Due to absence of neck there is no differentiation of buccal cavity and pharynx.

Question 6

3) Oesophagus

Answer 6

-Short wide tube which runs from gullet of buccopharyngeal cavity to the stomach.
- It is highly muscular which makes it easier for the passage of food from gullet to stomach.
- It acts as a passing channel from buccopharyngeal cavity to stomach.
- The mucous lining consists of goblet cells which secretes mucous which makes the oesophagus slippery.
- It opens to stomach.
- Histologically, Oesophagus is composed of : serosa, muscularis, submucosa and mucosa

Question 7

4) Stomach

Answer 7

• Widest part of the alimentary canal like J shaped which opens to intestine.
• It is guarded by flexible muscles called pyloric sphincter to regulate the food to small intestine.
• It serves as a place for storage and digestion of food where various chemical reactions and digestion occurs.

Question 8

5) Small Intestine :

Answer 8

• Longest part of alimentary canal, long, narrow tubular
• It is divided into duodenum and ileum
• It is the place of absorption of food and utilize by the body by structure called villi

Question 9

6) Large Intestine :

Answer 9

• Small Intestine is abruptly enlarged to form large intestine which consists of rectum only.
• Posteriorly , the rectum is joined to shoe shaped sac called cloacal chamber which stores feces and then thrown out by the cloacal aperture.

Question 10

Function of liver :

Answer 10

• Consists right, median and left lobe
• secretion of bile
• detoxification
• synthesis of urea
• production of heat
• blood cell production in fetus

Question 11

Function of Pancreas :

Answer 11

• Heterocrine gland
• Secretes trypsin , amylase for digestion of protein, fat, carbohydrate
• Insulin ang glycogen for regulation of blood sugar level.