Excretory Process
Most excretory systems produce urine by refining a filtrate derived from body fluids
Filtration
Filtering of body fluids
Reabsorption
Reclaiming valuable solutes
Secretion
Adding nonessential solutes and wastes from the body fluids to the filtrate
Excretion
Processed filtrate containing nitrogenous wastes, released from the body
Protonephridium
A protonephridium is a network of dead-end tubules connected to external openings
Metanephridia
Each segment of an earthworm has a pair of open-ended metanephridia
Malphigian Tubules
In insects and other terrestrial arthropods, Malpighian tubules remove nitrogenous wastes from hemolymph and function in osmoregulation