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| Digestive System of Grasshopper |
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| Digestion takes place in specialised cavities joined together to form a continuous canal. It is called the alimentary canal. |
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| Grasshopper - Digestive System |
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| The alimentary canal is divided into three main portions: |
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 Foregut |
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Midgut |
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Hindgut |
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| Foregut |
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| It consists of the mouth surrounded by the mouthparts. The mouth cavity is called the pharynx. It continues as the oesophagus that is short, narrow and thin-walled. The canal then enlarges into crop which is also thin-walled. The crop opens into short, muscular organ, the gizzard or the proventriculus. A pair of Salivaryglands lie outside and below the crop. |
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| Each salivary gland is branched, the secretions of all the branches pouring into a common duct. The two ducts, one of each side, open into the mouth cavity at the labium. The entire foregut is lined with chitin. In the gizzard, the chitin (a polysaccharide forming the major constituent in the exoskeleton of arthropods and in the cell walls of fungi) forms teeth and plate to facilitate grinding of the food. |
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| Midgut |
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| Midgut consists entirely of stomach or ventriculus. At the junction of the gizzard and stomach are six pairs of gastric caecae ('gastric' means pertaining to stomach). These are pouch-like structures arranged in a ring-like manner around the anterior end of the stomach. The anterior lobe of each pair of the caecae extends over the proventriculus and the posterior lobe extends over the ventriculus. |
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| The caecae secrete digestive juices and pour them into the stomach. The midgut is not lined by chitin or cuticle but by a peritrophic membrane. This membrane protects the stomach wall from abrasions and is fully permeable to enzymes and digested food. |
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| Hindgut |
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| Hindgut is a coiled structure consisting of anterior ileum, middle colon and posterior rectum. The rectum opens to the exterior through the anus. The hindgut is lined with cuticle. At the junction of the stomach and ileum are attached numerous long tubules called the Malpighian tubules. |
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| Mechanism of digestion |
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| Digestion starts at the mouth with the mandibles and the maxillae chewing the food. It is also acted upon by enzymes of salivary juice, the salivary carbohydrases which partially digest the food. The food is then swallowed with the help of lubrication provided by the salivary juice. |
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| The food then enters the oesophagus and then into the crop. Here, the masticated food is temporarily stored. |
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| The food then passes into the gizzard which acts as the grinding chamber. At the junction of the gizzard and the stomach is a valve called the pyloric valve. It allows the passage of only the thoroughly digested food into the stomach and also, prevents the regurgitation of food from the stomach. |
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| The ground food then enters the stomach. The digestive enzymes secreted by the gastric caecae act upon the food in the stomach. These enzymes include amylase, maltase, invertase, tryptase and lipase. The digested food is absorbed through the stomach walls into the surrounding space which is called the haemocoel. From here, it is transported to the different body parts. |
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| In the hindgut, absorption of water takes place and the undigested food is formed into almost dry pellets. These are excreted through the anus as faeces. |
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