The Digestive System of Cockroach consist of the alimentary canal and digestive glands. The alimentary canal also consist of mainly three regions such as , The Fore – gut or stomodaeum, the mid – gut or mesenteron and last one is the hind – gut or proctodaeum. The fore gut and hind gut are ectodermal and lined with cuticle, while the mid gut is ectoderm, whithout a cuticular linings. Alimentary canal is elongated and coiled.

Digestive System of Cockroach

I)Fore gut It is also called as mouth and situaited at the base of the pri oral cavity of buccal chamber i.e the fore gut is composed of pri oral cavity, mouth, pharynx , oesophagus ,corp and gizzard.

1.The pri-oral cavity:- is bounded in frount of the labrum ,posteriorly by the labium and each side a pair of mandibles and maxilla. in side the cavity the hypopharynx is present.

2.Mouth :- the mouth opens behind in to a short tribularpharynx .i.e lies on the roop of the pri-oral cavity

3.Pharynx:- The mouth lead in to a tubular pharynx which posses vertically upword and then it bends backword in an oesophagus.

4.Oesophagus:- The oesophagus is a narrow tubular passage which passes through the neck and gradually expands in to a thorax, finally taking a shape of sac like structure of abdominal and it open in to the crop.

5.Crop:- Crop is a bag like structure which is thin wall and muscular , which extends in to first two sigments of abdominal and it open in to gizzard.

6.Gizzard:-

The gizzard is round thick walled bag, continuous inner lining with thrown in to six powerful teeth. Behind each teeth is ring shaped cushion called as pulvillus. It consist of long back-wardly directed bristles. The teeth serve to ground while the bristal acts as a strainer, allowing only the well crushed food to pass on. The end of gizzard project into the mid-gut in the form of a funnel like narrow tube the stomodeal valve which prevent the passage of food from the mid-gut to the gizzard.

Midgut:- the gizzard is followed by short narrow tube lined with glandular endodermal cells. the anterior end of the midgut arises seven or eight blind tubular out growths called as hepatic-caeca. They projects into the hemocoel .

Hindgut:- it is the junction of mid-gut and hindgut . which is marked by 60 to 70 fine, yellow filamentous thread like processes which is called as malpighin tubules . which are execratory in function not a digestion the anterior region of mid-gut is formed of three parts namely ileum ,colon and rectum.

Ileum which is followed by a long and coiled colon. The colon ends into a broad rectum which opens by an anus lying posteriorly below the 10th tergum.

Digestive glands:- digestive glands of a cockroach is includes a salivary gland

Salivary gland

Cockroach have a pair of salivary gland which is located on a sides of a oesophagus. It consist of two pair of salivary gland and a pair of salivary receptacles. The duct of a two gland of a side unite into a salivary gland duct , which run forward and join the similar duct from the other side to form a common salivary gland duct. Similarly the duct of the two receptacles unite into a common salivary duct joins with the common receptacular duct to form a common salivary and receptacular duct which open on the hypo pharynx the salivary gland secrete a fruit called saliva.

Feeding and digestion

The cockroach is omnivorous feeding on any kind of materials like animal or plant materials, bits of paper, leather, bread, cloth etc. The food is located by the antennae and palps. It is masticated with the mandible. The laciniae, galeae of maxillae and glossae and paraglossae of the labium hold the food during the act of crushing. The labium and labrum prevent the loss of food from the jaws.

The food is mixed with saliva, poured in to the pre - oral cavity by the common salivary duct. The saliva contains an enzyme called amylase which digest starch in to glucose. The food is than pushed through the oesophagus in to the crop. The saliva continues it’s action on starch in the crop also.

Next the food passes to the gizzard. In the gizzard, the food is masticated by the cuticular teeth and is than filtered by the bristles. The secration of hepatic caeca contains proteolytic and lipolytic enzymes which digest proteins and lipids respectively. The digested food is absorbed in the mid gut and in the caeca. The rectum removes the excess amount of water and undigested food is egested through the anus as dry plates. Some of the absorbed food is stored as reserve in the form of fat, Glycogen, etc. In the fat bodies lying in the haemocoel.