This essay gives you background information about Dugesia, a type of flatworm. It'll tell you about the movement of the flatworm, the passage of food entering the body, and the functions of the structures on the body of a Dugesia.
An earthworm's body has more than 100 segments(Feldkamp, page 734). The worm anchors some of the middle segments by their setae and attracts the circular muscles infront of those segments to move (Feldkamp, page 734). Earthworms feed by ingesting the soil that they burrow (Feldkamp, page 734). The soil passes through the esophagus, the crop for temporary storage, and the gizzard to grind soil (Feldkamp, page 734). The digested organic compounds and nutrients are absorbed by the blood (Feldkamp, page 734). An earthworm has a closed circulatory system transport oxygen, carbon dioxide, nutrients, and wastes through the body (Feldkamp, page 735). Blood travels towards the posterior end by the ventral blood vessel, and returns back by a dorsal blood vessel (Feldkamp, page 735). Earthworms have no specialized respiratory organs (Feldkamp, page 735). Oxygen and carbon dioxide diffuse through the skin when it is moist (Feldkamp, page 735). The worm eliminates excess water through excretory tubules called nephridia (Feldkamp, page 735). The nervous system is made ip by a chain of ganglia and a ventral nerve cord (Feldkamp, page 735). One of the main functions of the cerebal ganglia is the process information from simple sensory structures that respond to light, touch, chemicals, moisture, temperature, and vibrations (Feldkamp, page 735). Eventhough some of the nerves are part of the segments, most of the sensory organs are concentrated at the anterior end (Feldkamp, page 735).
