The adult frog is carnivorous and captures animal prey using its muscular tongue, which has a bilobed tip. The digestive system includes a continuous alimentary canal together with accessory glands. Food passes from the mouth into the buccal region and pharynx, through the short oesophagus to the stomach, then along the small intestine to the rectum and cloaca.

The stomach stores and processes food through muscular movement and gastric secretions. Partly digested material, chyme, passes into the duodenum, the first part of the small intestine. Subsequent intestinal digestion and absorption transfer useful products into the internal transport system. The rectum handles material remaining in the canal before it leaves through the cloacal opening.

A liver or pancreas assists digestion but is not an extra chamber through which a swallowed insect travels. Secretions reach the alimentary canal through ducts. Trace food and digestive secretions as two different routes to avoid placing an accessory gland between stomach and intestine.

Egestion removes undigested food residues; excretion removes metabolic wastes such as urea. The cloaca can receive material associated with both routes, but a shared exit does not make the processes identical. In a sequence diagram, arrows indicate passage, not the size or anatomical spacing of organs.

Worked example: A swallowed prey item reaches the stomach through the oesophagus; bile later enters the intestinal region through a duct. Food does not first pass through the liver.

NCERT trap: An accessory gland is not part of the food’s continuous lumen; egestion and excretion are different despite sharing an exit.

NEET method: Trace the alimentary lumen first, then add glandular inputs as side branches.

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Structural Organisation in Animals

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