Alimentary Canal of a Cockroach

Alimentary Canal of a Cockroach

• The digestive system of a cockroach is divided into the foregut, midgut, and hindgut.
• Foregut: The foregut begins with the mouth and leads to a tubular pharynx. The pharynx opens into an oesophagus which is a sac-like structure that stores food. The crop is followed by a gizzard, which grinds food using muscular walls. The foregut is lined with 6-8 blind tubules called gastric caecae, which secrete digestive juices.
• Midgut: The midgut is a junction between the foregut and hindgut. It contains about 100-150 Malpighian tubules, which are involved in excretion. The midgut is lined with digestive cells and hepatic caeca, which secrete digestive enzymes.
• Hindgut: It starts with the ileum and continues to the rectum, where waste products are collected and expelled through the anus.
• Crop: A sac-like structure connecting the esophagus to the gizzard used for food storage.
• Gizzard: A muscular structure responsible for the grinding of food.
• Mesenteron (or Midgut): Contains digestive cells (Hepatic caeca) that further break down food, surrounded by Malpighian tubules.
• Malpighian tubules: These tubules remove excretory products from the body.
• Colon: Part of the hindgut for further material processing.
• Ileum: Part of the hindgut.
• Rectum: Part of the hindgut to store and expel waste material.
• Oesophagus: Muscular tube connecting the pharynx to the crop.

Cockroach Circulation

• The circulatory system of the cockroach is an open system.
• Blood (haemolymph) is circulated in spaces surrounding the organs (visceral organs) and bathed in the haemolymph.
• The heart is a long, muscular tube located along the dorsal midline of the thorax and abdomen.
• Blood from sinuses flows into funnel-shaped chambers (ostia) and is pumped through the aorta to the rest of the body.
• The digestive system is crucial and has associated structures like the salivary gland, crop, and gizzard.