The protonephridia of flatworms excrete water and conserve salts

Many flatworms, such as Planaria, live in fresh water. These animals excrete water through an elaborate network of tubules running throughout their bodies. The tubules end in flame cells, so called because each cell has a tuft of cilia projecting into the tubule. The beating of the cilia give the appearance of a flickering flame (Figure 51.4). A flame cell and a tubule together form a protonephridium (plural, protonephridia; from the Greek proto, "before," and nephros, "kidney").

Tissue fluid enters the tubules (how it does so is not entirely clear), and the beating of the cilia causes this fluid to flow through the tubules toward the animal's excretory pore. As it flows, the cells of the tubules modify the composition of the fluid. As the modified tubule fluid (urine) leaves the flatworm's body, it is less concentrated than the animal's tissue fluid, so ions are conserved and water is excreted by the protonephridium.

Tubule cells

Excretory pore

Tubule cells

Excretory pore

Protonephridia Planarian

51.4 Protonephridia in Flatworms The protonephridia of the flat-worm Planaria consist of tubules ending in flame cells.The tubule cells modify the composition of the fluid passing through them.

Was this article helpful?

0 -2
31 Days To Bigger Arms

31 Days To Bigger Arms

You can have significantly bigger arms in only 31 days. How much bigger? That depends on a lot of factors. You werent able to select your parents so youre stuck with your genetic potential to build muscles. You may have a good potential or you may be like may of the rest of us who have averages Potential. Download this great free ebook and start learns how to build your muscles up.

Get My Free Ebook


Responses

  • danait
    What are protonephridia in flatworms?
    8 years ago
  • lucille
    What are flame cells in flatworms?
    8 years ago
  • Hanno
    Why protonephridia are termed as flame cells?
    8 years ago
  • severi riihij
    Why protonephridia aretermed as flame cell?
    8 years ago

Post a comment