Cockroach Digestive System Short Notes

In this article we will discuss about the cockroach digestive system

Cockroach Digestive System

• Cockroach digestive system is responsible for digestion &absorption of food
• Cockroach digestive system includes alimentary canal and digestive glands

Alimentary canal

• The alimentary canal has been divided into three main regions: fore gut, mid gut and hind gut

Foregut (stomodeum)

• Starts from mouth, ending in gizzard & it’s lined internally by cuticle
• Mouth is ventral in position and surrounded by mouth parts
• Pharynx is short tube, opening into the oesophagus.
• Oesophagus ending in crop
• Crop is the largest part of foregut & serve as a reservoir for storing food
• Gizzard has outer thick circular muscles and thick inner six chitinous plate called teeth.
• Gizzard helps in grinding the food particles.
• Gizzard open in mid gut by stomodial valve

Mid gut or mesenteron

• It’s not lined by cuticle
• 4 pairs of tubules are seen at the junction of foregut and mid gut
• Gastric caeca secrete digestive juice
• Midgut forms the true stomach serving mainly for digestion and absorption

Hind gut or proctodaeum

• It’s broader than mid gut and lined internally by cuticle
• Thin tubules attached at the junction of hind gut and mid gut called malpighian tubules
• Malphigian tubules help in removal of excretory products from haemolymph
• Hind gut differentiated into ileum, colon and rectum
• The rectum opens out through anus

Digestive gland

• Digestive glands includes salivary glands, the inner lining of mid gut and hep­atic caeca

Salivary glands

• Pair of salivary glands lies one on each side of the thoracic cavity
• Salivary ducts of two sides unite to form a common duct
• These common duct open into the pharynx and near the base of hypopharynx

Hepatic caeca

• 6-8 small and tubular, finger like blind tubules called hepatic caeca
• They project freely into the heamocoel from the anterior part of mesenteron
• They secrete digestive juice

Glands of the midgut

• The cells of the lining epithelium of the midgut secrete digestive enzymes

How digestive system works in cockroach?

• Start from mouth, food comes in contact with saliva and passes through the oesophagus into the crop
• Enzymes of saliva act upon the food till it reaches the crop. Digestion of carbohydrate takes place
• Hepatic caeca release digestive juice in crop. Most of digestion occur in the crop.
• Food thoroughly grinded into a paste by gizzard
• Grinded food enter into midgut through stomodial valve
• Digestion completes in the anterior part of midgut
• Absorption of digested food mainly occurs in mid gut
• Distribution of digested food by heamocoelomic fluid
• Undigested food enter into the ileum
• Maximum absorption of H2O occurred in rectum by rectal papilla
• Undigested food passes out from the body via the anus