Digestive System of a Cockroach (Alimentary Canal)

The foregut is responsible for food intake and initial grinding. The entire inside is lined with a tough cuticle.

• Mouth and Pharynx: Food enters the mouth and passes through the short tubular pharynx.
• Esophagus: A narrow tube carrying food down.
• Crop: A large, sac-like structure where the swallowed food is temporarily stored.
• Gizzard (Proventriculus): Located right after the crop, it contains six highly chitinous, sharp 'teeth'. Its job is to violently crush and grind the solid food into fine particles.

This is the main site of digestion and absorption. It is not lined by cuticle.

• Hepatic Caeca: At the exact junction where the foregut meets the midgut, there is a ring of 6 to 8 blind tubes called Hepatic Caeca. They secrete powerful digestive juices (enzymes) into the midgut to break down the food.
• The digested nutrients are absorbed through the walls of the midgut directly into the cockroach's blood (hemolymph).

The hindgut is wider than the midgut and is responsible for waste removal.

• Malpighian Tubules: At the junction of the midgut and hindgut, there is a ring of 100-150 yellow, thread-like Malpighian tubules. These are actually excretory organs that pull nitrogenous waste (uric acid) out of the blood and dump it into the intestine.
• Ileum, Colon, and Rectum: The waste travels through these three parts. The rectum absorbs all remaining water from the waste, converting it into a dry, solid pellet.
• Anus: The dry waste is expelled out through the anus.