Question

Select the correct sequence of organs in the alimentary canal of cockroach starting from mouth:

• A. Pharynx→ Oesophagus →Crop→ Gizzard → Ileum→ Colon→ Rectum
• B. Pharynx→ Oesophagus→ Gizzard →Crop→Ileum → Colon→ Rectum
• C. Pharynx→ Oesophagus → Gizzard → Ileum → Crop →Colon→ Rectum
• D. Pharynx →Oesophagus→ Ileum → Crop→ Gizzard→ Colon → Rectum

Answer 1

The Correct Option is A

The alimentary canal of a cockroach, like most insects, is a long tube through which food is processed as it moves from the mouth to the anus. Let's go through the correct sequence of organs in the alimentary canal, starting from the mouth, to understand the correct answer:

1. Pharynx: The food enters the pharynx from the mouth. This is where the food starts its journey down the alimentary canal.
2. Oesophagus: After the pharynx, the food moves into the oesophagus. It's a narrow tube that conducts the food to the crop.
3. Crop: The oesophagus leads to a sac-like structure known as the crop. The crop functions as a storage organ where food is temporarily held and slightly moistened.
4. Gizzard: The gizzard follows the crop. It's responsible for grinding up the food with the help of muscular walls and bristles, aiding in digestion.
5. Ileum: Post the gizzard, the food enters the ileum. This part of the midgut is involved in enzyme secretion and initiation of the digestion process.
6. Colon: The ileum leads the food to the colon. The colon is where further digestion and absorption occur.
7. Rectum: Finally, the processed waste is passed into the rectum, which facilitates the expulsion of waste from the body.

Given these functions and order, the correct sequence is: Pharynx → Oesophagus → Crop → Gizzard → Ileum → Colon → Rectum.

This correctly corresponds with the option given in the question, which confirms this as the right answer. The other options present the sequence incorrectly by disrupting this pathway or confusing the order of some structures, such as swapping the Gizzard and Crop or incorrectly placing the Ileum before the Crop.