Question

This is the life cycle of Ascaris. Fill in the gaps between A to G mentioning the events at that stage.

• A. A. First moult occurs,B. Develops into rhabditiform (second larval stage)C. Larva hatches out in intestineD. Through the pulmonary artery reaches the lungsE. Travels through hepatic portal systemF. Fourth stage juvenile larva travels from alveoli, bronchioles and finally to the tracheaG. Fourth (final) moult occurs in intestine
• B. A. First moult occursB. Travels through hepatic portal systemC. Larva hatches out in intestineD. Develops into rhabditiform (second larval stage)E. Through the pulmonary artery reaches the lungsF. Fourth stage juvenile larva travels from alveoli, bronchioles and finally to the tracheaG Fourth (final) moult occurs in intestine
• C. A. First moult occursB. Develops into rhabditiform (second larval stage)C. Travels through hepatic portal system,D. Larva hatches out in intestineE. Through the pulmonary artery reaches the lungsF. Fourth stage juvenile larva travels from alveolibronchioles, bronchus and finally to the tracheaG. Fourth (final) moult occurs in intestine
• D. A. First moult occursB. Develops into rhabditiform (second larval stage)C. Larva hatches out in intestineD. Travels through hepatic portal systemE. Through the pulmonary artery reaches the lungsF. Fourth stage juvenile larva travels from alveoli, bronchioles and finally to the tracheaG. Fourth (final) moult occurs in intestine

Answer 1

Answer: (D)

A. First moult occurs

B. Develops into rhabditiform (second larval stage)

C. Larva hatches out in intestine

D. Travels through hepatic portal system

E. Through the pulmonary artery reaches the lungs

F. Fourth stage juvenile larva travels from alveoli, bronchioles and finally to the trachea

G. Fourth (final) moult occurs in intestine

Ascaris in infective eggs are ingested with contaminated food and water. The eggs hatch into larvae in the small intestine and penetrate the gut wall. It reaches the liver through portal system and then migrates to the lungs via herat through blood. After about 10 days they swallowed down the oesophagus. This migratory phase lasts for about two weeks during which the larvae undergo two additional moults. On arrival at the small intestine, the fourth moult occurs and the larvae form immature adult worms. Thus, the correct answer is option D.