Nephridium

As Nephridium ( gr nephros - kidney ) is called an organ for excretion of toxic degradation products. In the animal kingdom there are several types of nephridia:

• Protonephridia: They are the simplest excretory organs and are used mainly in animals without secondary body cavity before, so they are, for example, typical of flatworms ( Platyhelminthes ), and larvae of molluscs and annelids. In many cases, branched tubes each begin with a blind called Reuse scourge cell also Cyrtocyte or terminal cell. This creates a " eyelashes flame " (a constantly beating Cilienbündel ) the terminal cell, a flow of the liquid in the tube system into it. This creates a vacuum, and the tissue fluid is formed by the podocytes Reuse bars at the Cyrtocyte filtered ( ultrafiltration). This podocytes terminal cell and the channel of the adjacent cell forming of numerous interleaved feet which are separated only by fine crevices. They are covered by a basement membrane and thus provides the very liquid, a filter barrier dar. In their passage is created by "inside" the Protonephridiums a filtrate which is called the primary urine and up to cells and larger proteins still contains all existing substances in the blood. In the following the Cyrtocyte tubules, the tubules are now those parts of the primary urine, which can make use of the organism ( smaller proteins, saccharides, amino acids, ions), resumed reabsorbed. The Sekundärharn thus formed then contains mainly the organism harmful substances and is excreted by the outwardly opening Nephridialporen. Reuse scourge cell and duct cell probably arise in ontogeny independently and approach in the further development of each other. Here, the two cells formed by feet into each other, and there is the area surrounded by the cells tubular channel.

• Metanephridien: They are characteristic of the segmented worms ( Annelida ), probably also with ribbon worms ( Nemertini ) present for many mollusks ( Mollusca ) and crustaceans (Crustacea ) ( here maxillary or Antennennephridien called ). These are channels that are on a split hopper ( NEPHROSTOM ) are connected to the coelom and then out. The ultrafiltration takes first at the basement membrane of blood vessels by podocytes instead (see above), which are located at the eyelashes funnel at Coelomepithel. The driving force here is the blood pressure. The filtrate thus formed (primary ), as in the protonephridia withdrawn still usable parts of the tubule and reabsorbed so that the Sekundärharn can then open a closed Nephridialporus outward. A further development of a Metanephridiums is the nephron, the anatomical and functional unit of the vertebrate kidney.

• Malpighian tubules are typical of many Arthropods ( Arthropoda ) (otherwise Metanephridien ) such as spiders (Arachnida ), millipedes ( Myriapoda ) and insects (Insecta ).

• Anatomy (eddy lots)
• Urinary organ