BIOL 1002 Chapter : Ch 35 Notes
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Excretory system: the excretory system restores and maintains the proper internal regulation of these materials in the body despite differences in diet, simple excretory systems, the flame cells in flatworms are the simplest excretory system (see fig 35-1a). Network of tubes branching throughout the body. The tubes end at hollow bulbs called flame cells. Water and dissolved wastes are filtered into the bulbs. The cilia of the flame cell direct the fluid through tubes where water and nutrients are absorbed from the solution and more wastes are added from body cells. Eventually, the solution of concentrated wastes reach one of numerous pores in the skin and is released to the outside: the nephridia in earthworms and mollusks function as simple kidneys. In the earthworm nearly every segment contains a pair of nephridia (see fig 35-1c) Wastes and nutrients collected from the blood and tissues fills the body cavity (coelom).