Question

Draw a labeled diagram of the digestive system of the cockroach.

Answer 1

The digestive system of cockroach:

1. Cockroaches are insects that come under the order Blattodea.
2. In cockroaches, the digestive system comprises digestive glands and an alimentary canal.
3. The alimentary canal of cockroaches is differentiated into foregut, midgut, and hindgut.

Foregut:

It comprises of mouth, pharynx, esophagus, crop, and gizzard.

Midgut:

1. The second segment of the alimentary canal is the midgut or mesenteron.
2. The Hepatic caeca, which consists of six to eight ring-like, tubular structures, is located at the confluence of the foregut and midgut.
3. Their function is to secrete digestive juices to facilitate digestion.

Hindgut:

1. The ileum, colon, and rectum are parts of the hindgut, which is a coil-like structure.
2. The cockroach's excretory system, the malpighian tubules, eliminates metabolites and other nitrogenous products. It can be found where the midgut and hindgut meet.

Digestion in cockroaches:

1. In the buccal cavity, food intake is combined with saliva and transferred to the crop, an organ used for storage.
2. The food is then moved to the gizzard, where it is crushed by cuticular teeth. Only smaller particles can pass through the hair-like cushion and reach the gizzards.
3. The food is combined inside the gizzards with the digestive juices that the hepatic caeca and the inner lining of the midgut secrete. Glucose is absorbed by the hepatic caeca.
4. Excreta are sent to the hindgut for elimination from the body after nutritional absorption.