Long Answer
Medium difficulty • Structured explanation
Question 1
Long FormDescribe the complete digestive system of the frog, including the pathway of food, the role of digestive glands and the process of absorption.
- The digestive system consists of the alimentary canal and digestive glands. The canal is short because frogs are carnivores. Food is captured by the bilobed tongue and enters through the mouth into the buccal cavity, then passes to the pharynx, oesophagus, stomach, intestine, rectum and exits via the cloaca.
- HCl and gastric juices from the stomach walls act on food to produce partially digested chyme, which is then passed to the duodenum (first part of the small intestine).
- The duodenum receives bile from the gall bladder and pancreatic juice from the pancreas through a common bile duct. Bile emulsifies fats while pancreatic juice digests carbohydrates and proteins.
- Final digestion occurs in the intestine. Numerous finger-like projections called villi and microvilli on the inner wall of the intestine absorb the digested food, greatly increasing the surface area for absorption.
- The liver secretes bile stored in the gall bladder; the pancreas produces pancreatic juice containing digestive enzymes. Both glands play indispensable roles in chemical digestion.
- Undigested solid waste passes into the rectum and exits through the cloaca. The digestive system thus efficiently processes food from ingestion to absorption and waste expulsion.