Anatomy The three main parts of the body are the head, thorax, and adbomen. The wings are found on the thorax. Abdomen contains the breathing organs, heart, digestive system and sexual organs.
Nervous System Brain and ventral nerve cord Cells that detect and transmit sensations of pain (Nociceptors), but not proven that insects feel pain consciously
Digestive System Some insects drink their food, others chew most insects are herbivores, some are carnivores and some feed from decaying material Same function as in humans Most food is ingested in form of macromolecules, proteins, fats, polysaccharides, and nucleic acids and are broken down into smaller parts like amino acids and simple sugars (digestion) Main structure: alimentary canal (long enclosed tube running lengthwise through body) directing food from mouth to anus Insects also have paired salivary glands and salivary reservoirs found in the thorax Some have extra-oral digestion expelling digestive enzymes onto their food to break it down (flies). This has the advantage that insects can extract more nutrients from the food
Reproductive System The reproductive system consists of the sex glands, or gonads, the ducts through which the sexual products are carried to the exterior, and the accessory glands. two testes are made up of a variable number of follicles in which the spermatocytes mature and form packets of elongated spermatozoa. The ovarioles converge upon the two oviducts, and the oviducts unite to form a common oviduct down which the ripe eggs are discharged. Each ovariole consists of a germarium and a series of ovarial follicles. The germarium is a mass of undifferentiated cells that form oocytes, nurse cells, and follicular cells.
Circulartory System open, with most of the body fluid, or hemolymph, occupying cavities of the body and its appendages. one closed organ, called the dorsal vessel, extends from the hind end through the thorax to the head; it is a continuous tube with two regions, the heart or pumping organ, which is restricted to the abdomen, and the aorta, or conducting vessel, which extends forward through the thorax to the head.
Respiratory System consists of air-filled tubes or tracheae, which open at the surface of the thorax and abdomen through paired spiracles. muscular valves of the spiracles, closed most of the time, open only to allow the uptake of oxygen and the escape of carbon dioxide. tracheal tubes are continuous with the cuticle of the body surface. tracheoles insinuate themselves between cells, sometimes appearing to penetrate into them, and push deeply into the plasma membrane.