Question

Explain the digestive system of Cockroach with the help of a labelled sketch.

Answer 1

Divisions
The alimentary canal of the cockroach, present in its body cavity, is divided into foregut, midgut and hindgut.

Foregut

• The foregut has the following parts:
• Mouth- A space called the preoral cavity is enclosed by the mouth parts.
• Pharynx- The mouth leads to the pharynx.
• Esophagus- A tubular tube that leads into the crop.
• Crop- A sac like structure that stores food.
• Gizzard- Also called proventriculus, has an outer layer made up of thick circular muscles and an inner layer that has plates called teeth made up of chitin. Therefore the gizzard is used to grind food.

Midgut or Mesenteron

The midgut has the following parts:-

• Hepatic caeca- Found at the junction of foregut and midgut these are 6 to 8 in number. They are blind tubules that secrete digestive juices to the midgut.
• Malpighian tubules- Found in the junction of the midgut and hindgut, these yellow tubules (100 to 150 in number) help in the excretion of nitrogenous wastes.

Hindgut

Broader than the midgut, the hindgut has the following parts

• Ileum
• Colon
• Rectum- It opens out through the anus.

Diagram