SISTEMA EXCRETORES

_In the killers or sponges the waste accumulates in cells that then pour them into the general cavity of the body and then go outside, there is no excretory organ specialized in the flatworms there are channels terminated at one end in hair cells that collect the waste of the cavity of the body and in the other a pore that opens to the outside and removes them, this simple excretory apparatus is called protonephridium, in the arthropods are the tubes of malpighi intestinal sacs that collect the pours in the final portion of the intestine in the mollusks appear structures in the form of funnel nefrostoma and communicated with a tube that through a pore pour the waste outside are called metanefridios and in vertebrates have been transformed into the kidneys, the primitive kidney ponefros of the lower vertebrates is formed by several clusters of blood capillaries nephromas in communication with the coelom, a widening of the peritoneum that they are surrounded by a bowmann capsule and a renal tubule that, together with those of other nephrons, leads to a larger conduit of wolff that drains to the outside or to the cloaca, in the fish and amphibians the mesonephros appears in which the bowmann capsules do not open to the coelom, they filter the blood, in reptiles, birds and mammals the metanephros is formed, an authentic kidney formed by millions of nephrons and in which the wolf duct is transformed into a ureter that