Question

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

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

Answer 1

The correct option is A

Pharynx$$$$→ Esophagus→ Crop → Gizzard→ Ileum → Colon→ Rectum.

The correct option is A.

Explanation of the correct option:

Foregut:

1. The food particle is ingested through the mouth, which leads to the pharynx, a small tube-like structure.
2. It connects to another large tube-like structure called the esophagus.
3. This leads to a large sac-like structure known as a crop (Here, the food is stored prior to digestion).
4. A small cup-like structure beneath the crop is known as the gizzard or proventricular.
5. The thick cuticular layer lines the gizzard, and within this layer are six chitinous teeth-like structures that aid in cutting, grinding, and mastication of food.
6. In fact, a cuticular layer lines the entire foregut. There are 6-8 thread-like structures called hepatic cecum at the junction of the foregut and midgut.

Midgut:

1. It is the main site of digestion and has a coiled tube-like structure.
2. Malpighian tubules are 100-150 fine thread-like structures found at the junction of the midgut and hindgut.
3. They serve as an excretory organ.

Hindgut:

Their hindgut is composed of three sections: a narrow Ileum, a broad colon, and a sac-like rectum. After that, the digested food is expelled from the rectum.

Final answer: The correct sequence of organs in the alimentary canal of the cockroach starting from the mouth is Pharynx$$$$→ Esophagus→ Crop → Gizzard→ Ileum → Colon→ Rectum.