Digestive System in Cockroach:
Cockroach is an omnivorous. It can eat all kinds of organic matter. The nutrition in cockroach is holozoic.
PARTS OF ALIMENTARY CANAL:
The alimentary canal is divided into three main parts:
It is the first section of the alimentary canal. It consists of the mouth. The mouth followed by the buccal cavity. Inside the buccal cavity there is a tongue and hypo pharynx.
Buccal cavity opens into pharynx. The pharynx continues as the oesophagus. The oesophagus is a small, narrow tabular structure which is followed by a large sac like structure known as crop. The crop is a storage bag of the food material.
- Important point:
- The buccal cavity receives the common duct of salivary glands. Cockroach has a pair of salivary glands. Saliva contains amylase which converts starch into sugar.
- The oesophagus is short in the length tabular structure while crop is large pear shaped structure. But both are thin walled structure.
- Gizzard is a small, rounded thick walled with muscular chitins lining structure. It has six teeth. These teeth are sharp to grind the food. Gizzard masticates the food.
It is also known as mesentrone. It narrow, short and tabular structure. At the junction of gizzard and mesentron there are 6-7 small finger like projection known as hepathic caeca. These are hanging in the haemocoel ending blindly but opening in the midgut.
- Important point:
- The white color blood which filled in the body cavity is known as heamocoel.
Hepatic caeca produces digestive enzymes. With the help of these digestive enzymes the digestion of food takes place in the mesentron. After the digestion the nutrient such as carbohydrates, fats and proteins are absorbed by the midgut, especially in the more anterior parts including the caeca. All the nutrients are absorbed. Remaining nutrients and water are absorbed in the hindgut especially in the rectum.
It has three main parts:
It is a small, narrow, tabular part. It absorbs the remaining nutrients.
It is highly coiled structure.
It is broad last part of the hindgut. It stores undigested food for some time.
It is the last opening of digestive system. It opens to outside and undigested food is expel as feaces.