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insect-structure-07 - be expelled with the faeces The...

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Insect structure and function 7 Internal structures Haemocoel (blood space). The blood moves freely between the organs carrying digested food and excretory products. Generally there is no haemoglobin or blood cells. The blood also exerts hydraulic pressure on the cuticle during ecdysis or wing expansion. Oxygen is delivered via the tracheal system rather than the blood. Dorsal blood vessel pumps blood forward and releases it into the haemocoel so maintaining a slow circulation. The blood enters the dorsal vessel through openings in its side Gut . The foregut stores ingested food and passes it to the gizzard which helps to grind it into smaller fragments. Digestion and absorption take place in the mid gut. In the hind gut, water is absorbed from the faeces before they are egested. Excretory tubules extract nitrogenous waste from the blood, concentrate it to a semi-solid and pass it into the hind gut, to
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Unformatted text preview: be expelled with the faeces The ovarioles make up the ovary which produces the eggs. The eggs pass down the oviduct to be laid with the help of the ovipositor. As they pass the spermatheca, sperms are added and fertilise them. dorsal vessel thoracic segment haemocoel (blood space) gullet excretory tubule hind-gut abdominal segment mouth mandible first segment of leg salivary gland salivary duct fore-gut muscular gizzard mid-gut ovarioles oviduct Salivary gland secretes and delivers saliva through the salivary duct. The saliva contains digestive enzymes and, in the case of biting insects, an anti-coagulant spermatheca Spermatheca stores sperm from the last mating and adds it to the eggs as they are laid ovipositor The mandibles break up the food and pass it through the mouth to the gullet, the first part of the gut © D.G. Mackean...
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