Question

Describe the alimentary canal of a cockroach and its interaction.

Answer 1

Alimentary canal:

1. The alimentary canal which is a part of the digestive system is a continuous food passage through the body from mouth to anus.
2. Cockroaches are insects belonging to the phylum Arthropoda and are omnivorous in food habits.
3. The Alimentary canal or gut of cockroach has been divided into three main parts:

• Foregut
• Midgut
• Hindgut

Foregut

1. The foregut is composed of the mouth, pharynx, esophagus, crop, and gizzard.
2. Here, in this region food is masticated.
3. The mouth leads into a tubular pharynx which further leads to a tubular passage known as the esophagus.
4. Then the esophagus opens into a sac-like structure i.e. crop which stores the food.
5. The crop is further followed by a gizzard which helps in the grinding of the food particles and it is lined by the cuticle.

Midgut

1. The midgut creates a real gut called Mesenteron and comprises the whole stomach/ventriculus.
2. The midgut is lined by a peritrophic membrane and not by a cuticle.
3. At the junction of foregut and midgut, rings of 6 to 8 tubules i.e. hepatic or gastric caeca are present.

Hindgut

1. The hindgut is a coil-like structure and consists of the anterior ileum, middle colon, and posterior rectum.
2. The final one viz. the posterior rectum has its opening to the exterior via the anus.
3. It has a lining formed by the cuticle.

Six chitinous cuticular teeth are present in the gizzard which crush the food particles and act as a grinding chamber. The main site for food digestion and assimilation is the midgut.

Interaction with mankind:

1. Cockroaches interact with mankind by thriving in and around their habitat.
2. They are considered pests because they spoil food and contaminate it with their smelly excreta.
3. They can transmit a variety of diseases by contaminating food particles.