Flame cell

Flame cell is a specialized excretory cell found in the simplest freshwater invertebrates, including flatworms and nematodes. These cells function in osmoregulation and excretion, similar to the nephrons in more complex organisms' kidneys.

Structure

The flame cell is named for the flickering flame-like movement of the cilia within the cell. These cilia beat in a coordinated rhythm, creating a current that draws waste and excess water into the cell. The cell itself is shaped like a hollow bulb, with a single, long ciliated tuft extending into the lumen.

Function

The primary function of the flame cell is to maintain the organism's internal fluid balance and remove metabolic wastes. The beating cilia draw water and solutes from the surrounding tissues into the cell. The solutes are then transported across the cell membrane and into the surrounding interstitial fluid, where they are carried away by the organism's circulatory system.

Flame Cell System

In many organisms, flame cells are part of a larger excretory system known as a protonephridium. This system consists of a network of tubules leading from the flame cells to external pores. The tubules function in both reabsorption and secretion, further aiding in the regulation of the organism's internal environment.

Comparison with Other Excretory Systems

While flame cells perform a similar function to the nephrons in vertebrate kidneys, there are significant differences between the two. Nephrons are much more complex, with multiple specialized regions for filtration, reabsorption, and secretion. Flame cells, on the other hand, are much simpler, with a single cell performing all of these functions.

See Also

• Protonephridium
• Nephron
• Excretory system
• Osmoregulation